Pandas dataframe list comprehension multiple columns
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Show Learning machine learning with machine learning flashcards, Python ML book, or study with me videos. Using List Comprehensions With pandas20 Dec 2017 Preliminaries# Import modules
import pandas as pd
# Set ipython's max row display
pd.set_option('display.max_row', 1000)
# Set iPython's max column width to 50
pd.set_option('display.max_columns', 50)
Create an example dataframedata = {'name': ['Jason', 'Molly', 'Tina', 'Jake', 'Amy'],
'year': [2012, 2012, 2013, 2014, 2014],
'reports': [4, 24, 31, 2, 3]}
df = pd.DataFrame(data, index = ['Cochice', 'Pima', 'Santa Cruz', 'Maricopa', 'Yuma'])
df
List ComprehensionsAs a loop# Create a variable
next_year = []
# For each row in df.years,
for row in df['year']:
# Add 1 to the row and append it to next_year
next_year.append(row + 1)
# Create df.next_year
df['next_year'] = next_year
# View the dataframe
df
As list comprehension# Subtract 1 from row, for each row in df.year
df['previous_year'] = [row-1 for row in df['year']]
df
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