novicebioinforesearcher novicebioinforesearcher -4 years ago 101
Python Question

pandas multiple condition and add multiple column

I have a df:

import pandas as pd
df.head(20)
id ch start end strand
0 10:100026072-100029645(+) 10 100026072 100029645 +
1 10:110931880-110932381(+) 10 110931880 110932381 +
2 10:110932431-110933096(+) 10 110932431 110933096 +
3 10:111435307-111439556(-) 10 111435307 111439556 -
4 10:115954439-115964883(-) 10 115954439 115964883 -
5 10:115986231-116018509(-) 10 115986231 116018509 -
6 10:116500106-116500762(-) 10 116500106 116500762 -
7 10:116654355-116657389(-) 10 116654355 116657389 -
8 10:117146840-117147002(-) 10 117146840 117147002 -
9 10:126533798-126533971(-) 10 126533798 126533971 -
10 10:127687390-127688824(+) 10 127687390 127688824 +
11 10:19614164-19624369(-) 10 19614164 19624369 -
12 10:42537888-42543687(+) 10 42537888 42543687 +
13 10:61927486-61931038(-) 10 61927486 61931038 -
14 10:70699779-70700206(-) 10 70699779 70700206 -
15 10:76532243-76532565(-) 10 76532243 76532565 -
16 10:79336852-79337034(-) 10 79336852 79337034 -
17 10:79342487-79343173(+) 10 79342487 79343173 +
18 10:79373277-79373447(-) 10 79373277 79373447 -
19 10:82322045-82337358(+) 10 82322045 82337358 +

df.shape
(501, 5)

>>>df.dtypes
id object
ch object
start object
end object
strand object
dtype: object


Question:

I would like to perform multiple operations based on 'start' and 'end' column

first create two additional columns called

newstart newend

desiredoperation: if strand == '+':
df['newstart'] = end - int(27)
df['newend'] = end + 2
elif:
strand == '-'
df['newstart'] = start - int(3)
df['newend'] = start + 26


how can i do this using pandas, I found the link below but not sure how to execute it. If any one can provide a pseudo code will build up on it.
adding multiple columns to pandas simultaneously

Answer Source

You can do it using np.where, 2 lines but readable

df['newstart'] = np.where(df.strand == '+', df.end-int(27), df.start-int(3))
df['newend'] = np.where(df.strand == '+', df.end+int(2), df.start+int(26))

    id                         ch   start       end      strand newstart    newend
0   10:100026072-100029645(+)   10  100026072   100029645   +   100029618   100029647
1   10:110931880-110932381(+)   10  110931880   110932381   +   110932354   110932383
2   10:110932431-110933096(+)   10  110932431   110933096   +   110933069   110933098
3   10:111435307-111439556(-)   10  111435307   111439556   -   111435304   111435333
4   10:115954439-115964883(-)   10  115954439   115964883   -   115954436   115954465
5   10:115986231-116018509(-)   10  115986231   116018509   -   115986228   115986257
6   10:116500106-116500762(-)   10  116500106   116500762   -   116500103   116500132
7   10:116654355-116657389(-)   10  116654355   116657389   -   116654352   116654381
8   10:117146840-117147002(-)   10  117146840   117147002   -   117146837   117146866
9   10:126533798-126533971(-)   10  126533798   126533971   -   126533795   126533824
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