Convert long table to wide table in Python Pandas

long_table_to_wide_table_in_python_pandas.py

# Convert long table like
#       key long_column other_column_1
# ------------------------------------
# 0     Ann           1              A
# 1     Ann           3              A
# 2     Ann           5              A
# 3    John           3              B
# 4    John           5              B
# 5  George           1              A
# 6  George           3              A
# 
# to
# 
# wide_column_names wide_value1 wide_value3 wide_value5 other_column_1
# --------------------------------------------------------------------
# key                                                                 
# Ann                         1           3           5              A
# George                      1           3        None              A
# John                     None           3           5              B

import pandas as pd

data = pd.read_csv('data.csv')

# Group the long column values
data['key_group'] = data.groupby('key').cumcount()

# Use the long column values to build wide table column names
data['wide_column_names'] = 'wide_value_' + data['long_column']

# Generate wide table
wide_table = data.pivot(index='key', columns='wide_column_names', values='long_column')

# Attach other columns to wide table
data = data.set_index('key')
for other_column in ['other_column_1']:
    wide_table[other_column] = data.groupby(data.index).first()[other_column]

wide_table.to_csv('wide_table.csv', index=None)