unique

astropy.table.unique(input_table, keys=None, silent=False, keep='first')

Return a new table with unique rows, sorted by keys.

Parameters:

input_tableastropy:table-like

keysstr or list of str

Name(s) of column(s) used to create unique rows. Default is to use all columns.

silentbool

If True, masked value column(s) are silently removed from keys. If False, an exception is raised when keys contains masked value column(s). Default is False.

keep{‘first’, ‘last’, ‘none’}

Whether to keep the first or last row for each set of duplicates. If ‘none’, all rows that are duplicate are removed, leaving only rows that are already unique in the input. Default is ‘first’.

Returns:

unique_tableTable object

New table containing only the unique rows of input_table.

Examples

>>> from astropy.table import unique, Table
>>> import numpy as np
>>> table = Table(data=[[1,2,3,2,3,3],
... [2,3,4,5,4,6],
... [3,4,5,6,7,8]],
... names=['col1', 'col2', 'col3'],
... dtype=[np.int32, np.int32, np.int32])
>>> table
<Table length=6>
 col1  col2  col3
int32 int32 int32
----- ----- -----
    1     2     3
    2     3     4
    3     4     5
    2     5     6
    3     4     7
    3     6     8
>>> unique(table, keys='col1')
<Table length=3>
 col1  col2  col3
int32 int32 int32
----- ----- -----
    1     2     3
    2     3     4
    3     4     5
>>> unique(table, keys=['col1'], keep='last')
<Table length=3>
 col1  col2  col3
int32 int32 int32
----- ----- -----
    1     2     3
    2     5     6
    3     6     8
>>> unique(table, keys=['col1', 'col2'])
<Table length=5>
 col1  col2  col3
int32 int32 int32
----- ----- -----
    1     2     3
    2     3     4
    2     5     6
    3     4     5
    3     6     8
>>> unique(table, keys=['col1', 'col2'], keep='none')
<Table length=4>
 col1  col2  col3
int32 int32 int32
----- ----- -----
    1     2     3
    2     3     4
    2     5     6
    3     6     8
>>> unique(table, keys=['col1'], keep='none')
<Table length=1>
 col1  col2  col3
int32 int32 int32
----- ----- -----
    1     2     3