mirror of
https://github.com/donnemartin/data-science-ipython-notebooks.git
synced 2024-03-22 13:30:56 +08:00
1426 lines
24 KiB
Plaintext
1426 lines
24 KiB
Plaintext
{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"<small><i>This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://github.com/donnemartin/data-science-ipython-notebooks).</i></small>"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"# Data Structures\n",
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"\n",
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"* tuple\n",
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"* list\n",
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"* dict\n",
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"* set"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## tuple"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"A tuple is a one dimensional, fixed-length, immutable sequence.\n",
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"\n",
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"Create a tuple:"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 1,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"(1, 2, 3)"
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]
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},
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"execution_count": 1,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"tup = (1, 2, 3)\n",
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"tup"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Convert to a tuple:"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 2,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"tuple"
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]
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},
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"execution_count": 2,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"list_1 = [1, 2, 3]\n",
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"type(tuple(list_1))"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Create a nested tuple:"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 3,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"([1, 2, 3], (4, 5))"
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]
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},
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"execution_count": 3,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"nested_tup = ([1, 2, 3], (4, 5))\n",
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"nested_tup"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Access a tuple's elements by index O(1):"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 4,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"[1, 2, 3]"
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]
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},
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"execution_count": 4,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"nested_tup[0]"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Although tuples are immutable, their contents can contain mutable objects. \n",
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"\n",
|
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"Modify a tuple's contents:"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 5,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"[1, 2, 3, 4]"
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]
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},
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"execution_count": 5,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"nested_tup[0].append(4)\n",
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"nested_tup[0]"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
|
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"Concatenate tuples by creating a new tuple and copying objects:"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 6,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"(1, 3, 2, 4, 5, 6)"
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]
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},
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"execution_count": 6,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"(1, 3, 2) + (4, 5, 6)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Multiply tuples to copy references to objects (objects themselves are not copied):"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 7,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"('foo', 'bar', 'foo', 'bar')"
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]
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},
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"execution_count": 7,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"('foo', 'bar') * 2"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Unpack tuples:"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 8,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"data": {
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"text/plain": [
|
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"([1, 2, 3, 4], (4, 5))"
|
|
]
|
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},
|
|
"execution_count": 8,
|
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"metadata": {},
|
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"output_type": "execute_result"
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}
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],
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"source": [
|
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"a, b = nested_tup\n",
|
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"a, b"
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]
|
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},
|
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{
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"cell_type": "markdown",
|
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"metadata": {},
|
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"source": [
|
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"Unpack nested tuples:"
|
|
]
|
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},
|
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{
|
|
"cell_type": "code",
|
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"execution_count": 9,
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"metadata": {
|
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"collapsed": false
|
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},
|
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"outputs": [
|
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{
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|
"data": {
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"text/plain": [
|
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"(1, 2, 3, 4, 4, 5)"
|
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]
|
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},
|
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"execution_count": 9,
|
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"metadata": {},
|
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"output_type": "execute_result"
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}
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],
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"source": [
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"(a, b, c, d), (e, f) = nested_tup\n",
|
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"a, b, c, d, e, f"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
|
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"source": [
|
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"A common use of variable unpacking is when iterating over sequences of tuples or lists:"
|
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]
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},
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{
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"cell_type": "code",
|
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"execution_count": 10,
|
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"metadata": {
|
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"collapsed": false
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},
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"outputs": [
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{
|
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"name": "stdout",
|
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"output_type": "stream",
|
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"text": [
|
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"(1, 2, 3)\n",
|
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"(4, 5, 6)\n",
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"(7, 8, 9)\n"
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]
|
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}
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],
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"source": [
|
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"seq = [( 1, 2, 3), (4, 5, 6), (7, 8, 9)] \n",
|
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"for a, b, c in seq: \n",
|
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" print(a, b, c)"
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]
|
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
|
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"## list"
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]
|
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},
|
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{
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"cell_type": "markdown",
|
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"metadata": {},
|
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"source": [
|
|
"A list is a one dimensional, variable-length, mutable sequence.\n",
|
|
"\n",
|
|
"Create a list:"
|
|
]
|
|
},
|
|
{
|
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"cell_type": "code",
|
|
"execution_count": 11,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
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{
|
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"data": {
|
|
"text/plain": [
|
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"[1, 2, 3]"
|
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]
|
|
},
|
|
"execution_count": 11,
|
|
"metadata": {},
|
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"output_type": "execute_result"
|
|
}
|
|
],
|
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"source": [
|
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"list_1 = [1, 2, 3]\n",
|
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"list_1"
|
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]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Convert to a list:"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 12,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"list"
|
|
]
|
|
},
|
|
"execution_count": 12,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
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"type(list(tup))"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Create a nested list:"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 13,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"[(1, 2, 3), [4, 5]]"
|
|
]
|
|
},
|
|
"execution_count": 13,
|
|
"metadata": {},
|
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"output_type": "execute_result"
|
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}
|
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],
|
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"source": [
|
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"nested_list = [(1, 2, 3), [4, 5]]\n",
|
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"nested_list"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Access a list's elements by index O(1):"
|
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]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 14,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
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"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"[4, 5]"
|
|
]
|
|
},
|
|
"execution_count": 14,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
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],
|
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"source": [
|
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"nested_list[1]"
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]
|
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},
|
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{
|
|
"cell_type": "markdown",
|
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"metadata": {},
|
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"source": [
|
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"Append an element to a list O(1):"
|
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]
|
|
},
|
|
{
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"cell_type": "code",
|
|
"execution_count": 15,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"[(1, 2, 3), [4, 5], 6]"
|
|
]
|
|
},
|
|
"execution_count": 15,
|
|
"metadata": {},
|
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"output_type": "execute_result"
|
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}
|
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],
|
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"source": [
|
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"nested_list.append(6)\n",
|
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"nested_list"
|
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]
|
|
},
|
|
{
|
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"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
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"Insert an element to a list at a specific index (note that insert is expensive as it has to shift subsequent elements O(n)):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 16,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
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"outputs": [
|
|
{
|
|
"data": {
|
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"text/plain": [
|
|
"['start', (1, 2, 3), [4, 5], 6]"
|
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]
|
|
},
|
|
"execution_count": 16,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
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"nested_list.insert(0, 'start')\n",
|
|
"nested_list"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
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"Pop is expensive as it has to shift subsequent elements O(n). The operation is O(1) if pop is used for the last element.\n",
|
|
"\n",
|
|
"Remove and return an element from a specified index:"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 17,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"[(1, 2, 3), [4, 5], 6]"
|
|
]
|
|
},
|
|
"execution_count": 17,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"nested_list.pop(0)\n",
|
|
"nested_list"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Locates the first such value and remove it O(n):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 18,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"[[4, 5], 6]"
|
|
]
|
|
},
|
|
"execution_count": 18,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"nested_list.remove((1, 2, 3))\n",
|
|
"nested_list"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Check if a list contains a value O(n):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 19,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"True"
|
|
]
|
|
},
|
|
"execution_count": 19,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"6 in nested_list"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Concatenate lists by creating a new list and copying objects:"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 20,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"[1, 3, 2, 4, 5, 6]"
|
|
]
|
|
},
|
|
"execution_count": 20,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"[1, 3, 2] + [4, 5, 6]"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Extend a list by appending elements (faster than concatenating lists, as it does not have to create a new list):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 21,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"[[4, 5], 6, 7, 8, 9]"
|
|
]
|
|
},
|
|
"execution_count": 21,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"nested_list.extend([7, 8, 9])\n",
|
|
"nested_list"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"## dict"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"A dict is also known as a hash map or associative array. A dict is a mutable collection of key-value pairs.\n",
|
|
"\n",
|
|
"Note: Big O complexities are listed as average case, with most worst case complexities being O(n).\n",
|
|
"\n",
|
|
"Create a dict:"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 22,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"{'a': 'foo', 'b': [0, 1, 2, 3]}"
|
|
]
|
|
},
|
|
"execution_count": 22,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"dict_1 = { 'a' : 'foo', 'b' : [0, 1, 2, 3] }\n",
|
|
"dict_1"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Access a dict's elements by index O(1)"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 23,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"[0, 1, 2, 3]"
|
|
]
|
|
},
|
|
"execution_count": 23,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"dict_1['b']"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Insert or set a dict's elements by index O(1):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 24,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"{5: 'bar', 'a': 'foo', 'b': [0, 1, 2, 3]}"
|
|
]
|
|
},
|
|
"execution_count": 24,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"dict_1[5] = 'bar'\n",
|
|
"dict_1"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Check if a dict contains a key O(1):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 25,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"True"
|
|
]
|
|
},
|
|
"execution_count": 25,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"5 in dict_1"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Delete a value from a dict O(1):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 26,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"{'a': 'foo', 'b': [0, 1, 2, 3]}"
|
|
]
|
|
},
|
|
"execution_count": 26,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"dict_2 = dict(dict_1)\n",
|
|
"del dict_2[5]\n",
|
|
"dict_2"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Remove and return an element from a specified index O(1):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 27,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"name": "stdout",
|
|
"output_type": "stream",
|
|
"text": [
|
|
"[0, 1, 2, 3]\n",
|
|
"{'a': 'foo'}\n"
|
|
]
|
|
}
|
|
],
|
|
"source": [
|
|
"value = dict_2.pop('b')\n",
|
|
"print(value)\n",
|
|
"print(dict_2)"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Get or pop can be called with a default value if the key is not found. By default, get() will return None and pop() will throw an exception if the key is not found."
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 28,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"0"
|
|
]
|
|
},
|
|
"execution_count": 28,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"value = dict_1.get('z', 0)\n",
|
|
"value"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Return a default value if the key is not found:"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 29,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"name": "stdout",
|
|
"output_type": "stream",
|
|
"text": [
|
|
"[0, 1, 2, 3]\n",
|
|
"None\n"
|
|
]
|
|
}
|
|
],
|
|
"source": [
|
|
"print(dict_1.setdefault('b', None))\n",
|
|
"print(dict_1.setdefault('z', None))"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"By contrast to setdefault(), defaultdict lets you specify the default when the container is initialized, which works well if the default is appropriate for all keys:"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 30,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"defaultdict(<type 'list'>, {'b': ['bar', 'baz'], 'f': ['foo']})"
|
|
]
|
|
},
|
|
"execution_count": 30,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"from collections import defaultdict\n",
|
|
"\n",
|
|
"seq = ['foo', 'bar', 'baz']\n",
|
|
"first_letter = defaultdict(list)\n",
|
|
"for elem in seq:\n",
|
|
" first_letter[elem[0]].append(elem)\n",
|
|
"first_letter"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"dict keys must be \"hashable\", i.e. they must be immutable objects like scalars (int, float, string) or tuples whose objects are all immutable. Lists are mutable and therefore are not hashable, although you can convert the list portion to a tuple as a quick fix."
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 31,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"name": "stdout",
|
|
"output_type": "stream",
|
|
"text": [
|
|
"-9167918882415130555\n",
|
|
"-2725224101759650258\n"
|
|
]
|
|
}
|
|
],
|
|
"source": [
|
|
"print(hash('string'))\n",
|
|
"print(hash((1, 2, (3, 4))))"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Get the list of keys in no particular order (although keys() outputs the keys in the same order). In Python 3, keys() returns an iterator instead of a list."
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 32,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"['a', 'b', 5, 'z']"
|
|
]
|
|
},
|
|
"execution_count": 32,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"dict_1.keys()"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Get the list of values in no particular order (although values() outputs the keys in the same order). In Python 3, keys() returns an iterator instead of a list."
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 33,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"['foo', [0, 1, 2, 3], 'bar', None]"
|
|
]
|
|
},
|
|
"execution_count": 33,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"dict_1.values()"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Iterate through a dictionary's keys and values:"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 34,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"name": "stdout",
|
|
"output_type": "stream",
|
|
"text": [
|
|
"a foo\n",
|
|
"b [0, 1, 2, 3]\n",
|
|
"5 bar\n",
|
|
"z None\n"
|
|
]
|
|
}
|
|
],
|
|
"source": [
|
|
"for key, value in dict_1.items():\n",
|
|
" print key, value"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Merge one dict into another:"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 35,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"{5: 'bar',\n",
|
|
" 'a': 'foo',\n",
|
|
" 'b': [0, 1, 2, 3],\n",
|
|
" 'e': 'elephant',\n",
|
|
" 'f': 'fish',\n",
|
|
" 'z': None}"
|
|
]
|
|
},
|
|
"execution_count": 35,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"dict_1.update({'e' : 'elephant', 'f' : 'fish'})\n",
|
|
"dict_1"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Pair up two sequences element-wise in a dict:"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 36,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"{0: 6, 1: 5, 2: 4, 3: 3, 4: 2, 5: 1, 6: 0}"
|
|
]
|
|
},
|
|
"execution_count": 36,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"mapping = dict(zip(range(7), reversed(range(7))))\n",
|
|
"mapping"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"## set"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"A set is an unordered sequence of unique elements. \n",
|
|
"\n",
|
|
"Create a set:"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 37,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"{0, 1, 2, 3, 4, 5}"
|
|
]
|
|
},
|
|
"execution_count": 37,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"set_1 = set([0, 1, 2, 3, 4, 5])\n",
|
|
"set_1"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 38,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"{1, 2, 3, 5, 8, 13}"
|
|
]
|
|
},
|
|
"execution_count": 38,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"set_2 = {1, 2, 3, 5, 8, 13}\n",
|
|
"set_2"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Sets support set operations like union, intersection, difference, and symmetric difference."
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Union O(len(set_1) + len(set_2)):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 39,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"{0, 1, 2, 3, 4, 5, 8, 13}"
|
|
]
|
|
},
|
|
"execution_count": 39,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"set_1 | set_2"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Intersection O(min(len(set_1), len(set_2)):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 40,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"{1, 2, 3, 5}"
|
|
]
|
|
},
|
|
"execution_count": 40,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"set_1 & set_2"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Difference O(len(set_1)):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 41,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"{0, 4}"
|
|
]
|
|
},
|
|
"execution_count": 41,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"set_1 - set_2"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Symmetric Difference O(len(set_1)):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 42,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"{0, 4, 8, 13}"
|
|
]
|
|
},
|
|
"execution_count": 42,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"set_1 ^ set_2"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Subset O(len(set_3)):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 43,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"True"
|
|
]
|
|
},
|
|
"execution_count": 43,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"set_3 = {1, 2, 3}\n",
|
|
"set_3.issubset(set_2)"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Superset O(len(set_3)):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 44,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"True"
|
|
]
|
|
},
|
|
"execution_count": 44,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"set_2.issuperset(set_3)"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"metadata": {},
|
|
"source": [
|
|
"Equal O(min(len(set_1), len(set_2)):"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": 45,
|
|
"metadata": {
|
|
"collapsed": false
|
|
},
|
|
"outputs": [
|
|
{
|
|
"data": {
|
|
"text/plain": [
|
|
"True"
|
|
]
|
|
},
|
|
"execution_count": 45,
|
|
"metadata": {},
|
|
"output_type": "execute_result"
|
|
}
|
|
],
|
|
"source": [
|
|
"{1, 2, 3} == {3, 2, 1}"
|
|
]
|
|
}
|
|
],
|
|
"metadata": {
|
|
"kernelspec": {
|
|
"display_name": "Python 2",
|
|
"language": "python",
|
|
"name": "python2"
|
|
},
|
|
"language_info": {
|
|
"codemirror_mode": {
|
|
"name": "ipython",
|
|
"version": 2
|
|
},
|
|
"file_extension": ".py",
|
|
"mimetype": "text/x-python",
|
|
"name": "python",
|
|
"nbconvert_exporter": "python",
|
|
"pygments_lexer": "ipython2",
|
|
"version": "2.7.10"
|
|
}
|
|
},
|
|
"nbformat": 4,
|
|
"nbformat_minor": 0
|
|
}
|