Removed unwanted characters from string using pandas

I have the following dataframe:

df = pd.DataFrame({'A': ['2.5cm','2.5cm','2.56”','1.38”','2.2”','0.8 in','$18.00','4','2"']})

which looks like:

  A
2.5cm
2.5cm
2.56”
1.38”
2.2”
0.8 in
$18.00
4
2"

I want to remove all characters except for the decimal points.

The output should be:

 A
2.5
2.5
2.56
1.38
2.2
0.8
18.00
4
2

Here is what I’ve tried:

df['A'] = df.A.str.replace(r"[a-zA-Z]", '')
df['A'] = df.A.str.replace('\W', '')

but this is stripping out everything including the decimal point.

Any suggestions would be greatly appreciated.

Thank you in advance

>Solution :

You can use str.extract to extract only the floating points:

df['A'] = df['A'].astype(str).str.extract(r'(\d+.\d+|\d)').astype('float')

Output:

       A
0   2.50
1   2.50
2   2.56
3   1.38
4   2.20
5   0.80
6  18.00
7   4.00
8   2.00