mirror of
https://github.com/donnemartin/data-science-ipython-notebooks.git
synced 2024-03-22 13:30:56 +08:00
143 lines
3.4 KiB
Python
143 lines
3.4 KiB
Python
{
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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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"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)."
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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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"# Files\n",
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"\n",
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"* Read a File\n",
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"* Write a File\n",
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"* Read and Write UTF-8"
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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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"## Read a File\n",
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"\n",
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"Open a file in read-only mode.<br\\>\n",
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"Iterate over the file lines. rstrip removes the EOL markers.<br\\>"
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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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"name": "stdout",
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"output_type": "stream",
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"text": [
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"class TypeUtil:\n",
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"\n",
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" @classmethod\n",
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" def is_iterable(cls, obj):\n",
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" \"\"\"Determines if obj is iterable.\n",
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"\n",
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" Useful when writing functions that can accept multiple types of\n",
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" input (list, tuple, ndarray, iterator). Pairs well with\n",
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" convert_to_list.\n",
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" \"\"\"\n",
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" try:\n",
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" iter(obj)\n",
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" return True\n",
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" except TypeError:\n",
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" return False\n",
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"\n",
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" @classmethod\n",
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" def convert_to_list(cls, obj):\n",
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" \"\"\"Converts obj to a list if it is not a list and it is iterable,\n",
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" else returns the original obj.\n",
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" \"\"\"\n",
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" if not isinstance(obj, list) and cls.is_iterable(obj):\n",
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" obj = list(obj)\n",
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" return obj\n"
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]
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}
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],
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"source": [
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"old_file_path = 'type_util.py'\n",
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"with open(old_file_path, 'r') as old_file:\n",
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" for line in old_file:\n",
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" print(line.rstrip())"
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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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"## Write to a file\n",
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"\n",
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"Create a new file overwriting any previous file with the same name, write text, then close the file:"
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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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"source": [
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"new_file_path = 'hello_world.txt'\n",
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"with open(new_file_path, 'w') as new_file:\n",
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" new_file.write('hello world!')"
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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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"## Read and Write UTF-8"
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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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"source": [
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"import codecs\n",
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"with codecs.open(\"hello_world_new.txt\", \"a\", \"utf-8\") as new_file:\n",
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" with codecs.open(\"hello_world.txt\", \"r\", \"utf-8\") as old_file: \n",
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" for line in old_file:\n",
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" new_file.write(line + '\\n')"
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]
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 2",
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"language": "python",
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"name": "python2"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 2
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython2",
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"version": "2.7.10"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 0
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}
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