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"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Pandas Cleaning\n",
"* Clean\n",
"* Transform\n",
"* Merge\n",
"* Reshape\n",
"* Concatenate"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from pandas import Series, DataFrame\n",
"import pandas as pd"
],
"language": "python",
"metadata": {},
"outputs": [],
"prompt_number": 1
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Check for matching values in a specific column for replacement:"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"data_1 = {'state' : ['VA', 'VA', 'VA', 'MD', 'MD'],\n",
" 'year' : [2012, 2013, 2014, 2014, 2015],\n",
" 'pop' : [5.0, 5.1, 5.2, 4.0, 4.1]}\n",
"df_1 = DataFrame(data_1)\n",
"df_1"
],
"language": "python",
"metadata": {},
"outputs": [
{
"html": [
"
\n",
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\n",
" \n",
" \n",
" | \n",
" pop | \n",
" state | \n",
" year | \n",
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\n",
" \n",
" \n",
" \n",
" 0 | \n",
" 5.0 | \n",
" VA | \n",
" 2012 | \n",
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" \n",
" 1 | \n",
" 5.1 | \n",
" VA | \n",
" 2013 | \n",
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" 2 | \n",
" 5.2 | \n",
" VA | \n",
" 2014 | \n",
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" 3 | \n",
" 4.0 | \n",
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" 2014 | \n",
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" 4 | \n",
" 4.1 | \n",
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\n",
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"metadata": {},
"output_type": "pyout",
"prompt_number": 2,
"text": [
" pop state year\n",
"0 5.0 VA 2012\n",
"1 5.1 VA 2013\n",
"2 5.2 VA 2014\n",
"3 4.0 MD 2014\n",
"4 4.1 MD 2015"
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}
],
"prompt_number": 2
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"df_1[df_1['state'] == 'VA']"
],
"language": "python",
"metadata": {},
"outputs": [
{
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\n",
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" pop | \n",
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" 0 | \n",
" 5.0 | \n",
" VA | \n",
" 2012 | \n",
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" 5.1 | \n",
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" 2013 | \n",
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" 2 | \n",
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" \n",
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"metadata": {},
"output_type": "pyout",
"prompt_number": 3,
"text": [
" pop state year\n",
"0 5.0 VA 2012\n",
"1 5.1 VA 2013\n",
"2 5.2 VA 2014"
]
}
],
"prompt_number": 3
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Replace all occurrences of a string with another string, in place (no copy):"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"df_1.replace('VA', 'VIRGINIA', inplace=True)\n",
"df_1"
],
"language": "python",
"metadata": {},
"outputs": [
{
"html": [
"\n",
"
\n",
" \n",
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" | \n",
" pop | \n",
" state | \n",
" year | \n",
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" 0 | \n",
" 5.0 | \n",
" VIRGINIA | \n",
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" 3 | \n",
" 4.0 | \n",
" MD | \n",
" 2014 | \n",
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" \n",
" 4 | \n",
" 4.1 | \n",
" MD | \n",
" 2015 | \n",
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\n",
" \n",
"
\n",
"
"
],
"metadata": {},
"output_type": "pyout",
"prompt_number": 4,
"text": [
" pop state year\n",
"0 5.0 VIRGINIA 2012\n",
"1 5.1 VIRGINIA 2013\n",
"2 5.2 VIRGINIA 2014\n",
"3 4.0 MD 2014\n",
"4 4.1 MD 2015"
]
}
],
"prompt_number": 4
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"In a specified column, replace all occurrences of a string with another string, in place (no copy):"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"df_1.replace({'state' : { 'MD' : 'MARYLAND' }}, inplace=True)\n",
"df_1"
],
"language": "python",
"metadata": {},
"outputs": [
{
"html": [
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" 0 | \n",
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" VIRGINIA | \n",
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" 2013 | \n",
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" 2 | \n",
" 5.2 | \n",
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" 3 | \n",
" 4.0 | \n",
" MARYLAND | \n",
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" 4 | \n",
" 4.1 | \n",
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],
"metadata": {},
"output_type": "pyout",
"prompt_number": 5,
"text": [
" pop state year\n",
"0 5.0 VIRGINIA 2012\n",
"1 5.1 VIRGINIA 2013\n",
"2 5.2 VIRGINIA 2014\n",
"3 4.0 MARYLAND 2014\n",
"4 4.1 MARYLAND 2015"
]
}
],
"prompt_number": 5
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Concatenate two DataFrames:"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"data_2 = {'state' : ['NY', 'NY', 'NY', 'FL', 'FL'],\n",
" 'year' : [2012, 2013, 2014, 2014, 2015],\n",
" 'pop' : [6.0, 6.1, 6.2, 3.0, 3.1]}\n",
"df_2 = DataFrame(data_2)\n",
"df_2"
],
"language": "python",
"metadata": {},
"outputs": [
{
"html": [
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\n",
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" pop | \n",
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" year | \n",
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" 0 | \n",
" 6.0 | \n",
" NY | \n",
" 2012 | \n",
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" 6.1 | \n",
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" 2 | \n",
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" 2014 | \n",
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" 3.0 | \n",
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"metadata": {},
"output_type": "pyout",
"prompt_number": 6,
"text": [
" pop state year\n",
"0 6.0 NY 2012\n",
"1 6.1 NY 2013\n",
"2 6.2 NY 2014\n",
"3 3.0 FL 2014\n",
"4 3.1 FL 2015"
]
}
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"prompt_number": 6
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"df_3 = pd.concat([df_1, df_2])\n",
"df_3"
],
"language": "python",
"metadata": {},
"outputs": [
{
"html": [
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\n",
" \n",
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" MARYLAND | \n",
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" 4 | \n",
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"prompt_number": 7,
"text": [
" pop state year\n",
"0 5.0 VIRGINIA 2012\n",
"1 5.1 VIRGINIA 2013\n",
"2 5.2 VIRGINIA 2014\n",
"3 4.0 MARYLAND 2014\n",
"4 4.1 MARYLAND 2015\n",
"0 6.0 NY 2012\n",
"1 6.1 NY 2013\n",
"2 6.2 NY 2014\n",
"3 3.0 FL 2014\n",
"4 3.1 FL 2015"
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