Install: pip install virtualenv
Create: virtualenv my_project
Select python version: virtualenv -p /usr/bin/python2.7 my_project
Activate (Use): source my_project/bin/activate
Dectivate (Exit): deactivate
See working directory: os.listdir('./')
Change working directory: os.chdir('dir')
Add folder to path: sys.path.append('/path/to/library')
import pandas as pd
Open: pd.read_csv(filename, header=True)
Write name.to_csv(filename, header=True)
Drop row: name.drop(['col1','col2'], inplace=True)
Drop column: name.drop(['col1','col2'], axis=1, inplace=True)
Join on column: result = data1.set_index('id').join(data2.set_index('id'))
Get unique values in column: data['col1'].unique()
Get frequency of values in a column: data['col1'].value_counts()