P from a to z

1. filtering

1.1. Step 1 .< or > , False or True Step 2 .Filter =

1.1.1. Stats [Filter]

1.1.1.1. EX: Stats[stats. birthrate > 40 ]

1.2. & , 交集

1.2.1. Ex: Stats [ Filter & Filter 2]

1.2.2. EX : Stats [(stats brithrate > 40)] & [(stats internetuser < 2 )]

1.3. Extract group

1.3.1. ==

1.3.1.1. example: stats [stats.incomegroup == "high income"]

1.4. Unique category

1.4.1. unique ()