datascience.tables.Table.pivot

Table.pivot(columns, rows, values=None, collect=None, zero=None)

Generate a table with a column for each unique value in columns, with rows for each unique value in rows. Each row counts/aggregates the values that match both row and column based on collect.

Args:

columns – a single column label or index, (str or int),

used to create new columns, based on its unique values.

rows – row labels or indices, (str or int or list),

used to create new rows based on it’s unique values.

values – column label in table for use in aggregation.

Default None.

collect – aggregation function, used to group values

over row-column combinations. Default None.

zero – zero value to use for non-existent row-column

combinations.

Raises:

TypeError – if collect is passed in and values is not,

vice versa.

Returns:

New pivot table, with row-column combinations, as specified, with aggregated values by collect across the intersection of columns and rows. Simple counts provided if values and collect are None, as default.

>>> titanic = Table().with_columns('age', make_array(21, 44, 56, 89, 95
...    , 40, 80, 45), 'survival', make_array(0,0,0,1, 1, 1, 0, 1),
...    'gender',  make_array('M', 'M', 'M', 'M', 'F', 'F', 'F', 'F'),
...    'prediction', make_array(0, 0, 1, 1, 0, 1, 0, 1))
>>> titanic
age  | survival | gender | prediction
21   | 0        | M      | 0
44   | 0        | M      | 0
56   | 0        | M      | 1
89   | 1        | M      | 1
95   | 1        | F      | 0
40   | 1        | F      | 1
80   | 0        | F      | 0
45   | 1        | F      | 1
>>> titanic.pivot('survival', 'gender')
gender | 0    | 1
F      | 1    | 3
M      | 3    | 1
>>> titanic.pivot('prediction', 'gender')
gender | 0    | 1
F      | 2    | 2
M      | 2    | 2
>>> titanic.pivot('survival', 'gender', values='age', collect = np.mean)
gender | 0       | 1
F      | 80      | 60
M      | 40.3333 | 89
>>> titanic.pivot('survival', make_array('prediction', 'gender'))
prediction | gender | 0    | 1
0          | F      | 1    | 1
0          | M      | 2    | 0
1          | F      | 0    | 2
1          | M      | 1    | 1
>>> titanic.pivot('survival', 'gender', values = 'age')
Traceback (most recent call last):
   ...
TypeError: values requires collect to be specified
>>> titanic.pivot('survival', 'gender', collect = np.mean)
Traceback (most recent call last):
   ...
TypeError: collect requires values to be specified