Pandas Cheat Sheet

pandas_cheat_sheet.py

import pandas as pd
import numpy as np


####################################
# BASICS
####################################

# load from CSV
# see https://chrisalbon.com/python/data_wrangling/pandas_dataframe_importing_csv/
df = pd.read_csv('pandas_dataframe_importing_csv/example.csv')

# Column Lookup
# The two following are equivalent.
df['foo']
df.foo


####################################
# COLUMN WIZARDRY
####################################

# Delete a column
del df['worthless']

# Create new column based on values of other columns
df['c'] = df.apply(lambda row: row.a + row.b, axis=1)

# Create column with arbitrary function
def foo(a, b):
  return a + b
df['c'] = df.apply(lambda row: foo(row['a'], row.b), axis=1)


####################################
# Stats
df['weight'].mean()

# Categories in categorical data
df['category_field'].cat.categories.tolist()