Pandas Extract Number from String

Question

Given the following data frame:

import pandas as pd
import numpy as np
df = pd.DataFrame({'A':['1a',np.nan,'10a','100b','0b'],
                   })
df

    A
0   1a
1   NaN
2   10a
3   100b
4   0b

I'd like to extract the numbers from each cell (where they exist). The desired result is:

I know it can be done with str.extract, but I'm not sure how.

score 84 · Accepted Answer · answered Jun 07 '16 at 15:39

84

Give it a regex capture group:

df.A.str.extract('(\d+)')

Gives you:

0      1
1    NaN
2     10
3    100
4      0
Name: A, dtype: object

answered Jun 07 '16 at 15:39

Jon Clements

132,101
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237
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1

how could I do it when there is a comma like : `6,000 a` – Steven G Jul 01 '17 at 15:02
1

@StevenG strip out commas first? – Jon Clements Jul 01 '17 at 17:13
1

As of 2020, this codes gives a FutureWarning. You get around it by adding the parameter `expand=False` to the `extract` – lebelinoz Apr 21 '20 at 02:44
1

This doesn't work if there is number after alphabets – Upasana Mittal Apr 24 '20 at 15:02
This does not work for my column with number and units: `0.7 mg ` – mLstudent33 Oct 16 '20 at 00:03

score 5 · Answer 2 · answered Jul 07 '17 at 00:32

5

To answer @Steven G 's question in the comment above, this should work:

df.A.str.extract('(^\d*)')

answered Jul 07 '17 at 00:32

Taming

87
1
5

score 5 · Answer 3 · answered Oct 30 '20 at 00:06

5

U can replace your column with your result using "assign" function:

df = df.assign(A = lambda x: x['A'].str.extract('(\d+)'))

answered Oct 30 '20 at 00:06

Mehdi Golzadeh

2,409
1
14
26

Pandas Extract Number from String

3 Answers3

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