add_column

In [1]:

# https://tibble.tidyverse.org/reference/add_column.html

from datar import f
from datar.tibble import *
from datar.base import seq
from datar.core.names import NameNonUniqueError

%run nb_helpers.py
nb_header(add_column)

# https://tibble.tidyverse.org/reference/add_column.html from datar import f from datar.tibble import * from datar.base import seq from datar.core.names import NameNonUniqueError %run nb_helpers.py nb_header(add_column)

Try this notebook on binder.

★ add_column

¶

Add one or more columns to an existing data frame.¶

Args:¶

  _data: Data frame to append to
  *args: and
  **kwargs: Name-value pairs to add to the data frame
  _before: and
  _after: Column index or name where to add the new columns
    (default to add after the last column)

  _dtypes: The dtypes for the new columns, either a uniform dtype or a
    dict of dtypes with keys the column names

Returns:¶

  The dataframe with the added columns

In [2]:

df = tibble(x=seq(1,3), y=seq(3,1))
df >> add_column(z=seq(-1,1), w=0)

df = tibble(x=seq(1,3), y=seq(3,1)) df >> add_column(z=seq(-1,1), w=0)

Out[2]:

	x	y	z	w
	<int64>	<int64>	<int64>	<int64>
0	1	3	-1	0
1	2	2	0	0
2	3	1	1	0

In [3]:

df >> add_column(z=seq(-1,1), _before=f.y)

df >> add_column(z=seq(-1,1), _before=f.y)

Out[3]:

	x	z	y
	<int64>	<int64>	<int64>
0	1	-1	3
1	2	0	2
2	3	1	1

In [4]:

# You can't overwrite existing columns
try:
    df >> add_column(x = seq(4,6))
except NameNonUniqueError as err:
    print(err)

# You can't overwrite existing columns try: df >> add_column(x = seq(4,6)) except NameNonUniqueError as err: print(err)

Names must be unique: x

In [5]:

# You can't create new observations
with try_catch():
    df >> add_column(z = seq(1,5))

# You can't create new observations with try_catch(): df >> add_column(z = seq(1,5))

[ValueError] Value has incompatible index.