pandas Boolean indexing of dataframes Masking data based on column value
Example
This will be our example data frame:
color name size
0 red rose big
1 blue violet small
2 red tulip small
3 blue harebell small
Accessing a single column from a data frame, we can use a simple comparison == to compare every element in the column to the given variable, producing a pd.Series of True and False
df['size'] == 'small'
0 False
1 True
2 True
3 True
Name: size, dtype: bool
This pd.Series is an extension of an np.array which is an extension of a simple list, Thus we can hand this to the __getitem__ or [] accessor as in the above example.
size_small_mask = df['size'] == 'small'
df[size_small_mask]
color name size
1 blue violet small
2 red tulip small
3 blue harebell small
