Pandas Extract Number from String

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:

    A
0   1
1   NaN
2   10
3   100
4   0

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

Answers:

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Method 1

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

Method 2

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

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

Method 3

U can replace your column with your result using “assign” function:

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

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0