Revalue strings in a column using regular expression in Python

Question

I have a dataset with a column value :

0      TCGA-A2-A0T2
1      TCGA-A2-A0CM
2      TCGA-BH-A18V
3      TCGA-BH-A18Q
4      TCGA-BH-A0E0

However, I want to change it to:

A0T2
A0CM
A18V
A18Q
A0E0

I have tried code such as

df1['Complete TCGA ID'].str.extract('TCAG-(.*)-.*')

But it only returns NA. I really don't know how to figure out regular expression in this case. Can anyone please help? Thanks so much in advance!

Jan · Accepted Answer · 2020-08-16 12:13:33Z

2

You are looking for

df1['new_column'] = df1['Complete TCGA ID'].str.extract(r'-([^-]+)$')

answered Aug 16, 2020 at 12:13

Jan

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Comments

The fourth bird · Accepted Answer · 2020-08-16 12:23:18Z

2

It should be TCGA instead, and you can match till the last - and then capture the rest in group 1.

TCGA.*-(.*)

Or a bit more precise match for the example data:

^TCGA-[A-Z0-9]+-([A-Z0-9]+)$

answered Aug 16, 2020 at 12:15

The fourth bird

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