select() Method

Teradata® Python Package User Guide

brand
Teradata Vantage
prodname
Teradata Python Package
vrm_release
16.20
category
User Guide
featnum
B700-4006-098K

Use the select() method to select columns in a DataFrame. The function takes a select expression as an argument and returns a new DataFrame with the selected columns. The expression can be a single column name, a list of column names, or a list of column name lists.

Multicolumn selection of the same column (for example, df.select(['col1', 'col1'])) is not supported.

Examples Prerequisite

Assume the table "admissions_train" exists and its index column is id. And a DataFrame "df" is created based on this table using the command:

>>> df = DataFrame("admissions_train")
>>> df
    masters   gpa     stats programming admitted
id
5        no  3.44    novice      novice        0
7       yes  2.33    novice      novice        1
22      yes  3.46    novice    beginner        0
17       no  3.83  advanced    advanced        1
13       no  4.00  advanced      novice        1
19      yes  1.98  advanced    advanced        0
36       no  3.00  advanced      novice        0
15      yes  4.00  advanced    advanced        1
34      yes  3.85  advanced    beginner        0
40      yes  3.95    novice    beginner        0

Example: Expression is single column name

>>> df.select("id")
Empty DataFrame
Columns: []
Index: [22, 34, 13, 19, 15, 38, 26, 5, 36, 17]

Example: Expression is list of column names

>>> df.select(["id", "masters", "gpa"])
    masters   gpa
id
5        no  3.44
36       no  3.00
15      yes  4.00
17       no  3.83
13       no  4.00
40      yes  3.95
7       yes  2.33
22      yes  3.46
34      yes  3.85
19      yes  1.98

Example: Expression is list of column name lists

>>> df.select([['id', 'masters', 'gpa']])
    masters   gpa
id
5        no  3.44
34      yes  3.85
13       no  4.00
40      yes  3.95
22      yes  3.46
19      yes  1.98
36       no  3.00
15      yes  4.00
7       yes  2.33
17       no  3.83