Extract continuous numeric characters from a string in Python

[Robotguy]

I am interested in extracting a number that appears after a set of characters ('AA='). However, the issue is I: (i) am not aware how long the number is, (ii) don't know what appears right after the number (could be a blank space or ANY character except 0-9, consider that I do not know what these characters could be but they are definitely not 0-9).

Given below are few of many inputs that I can have.

Line 1: 123 NUBA AA=1.2345 $BB=1234.55
Line 2: 123 NUBA MM AA=1.2345678&BB=1234.55
Line 3: 123 NUBA RRNJH AA=1.2#ALPHA
...

The result should be: 1.2345 1.2345678 1.2 for each respective line above.

PS: I know how to use .find and get the starting location of AA= but that is not very helpful for the above two conditions. Also, I understand one way could be to loop through each character after after AA= and break if a blank space or anything except 0-9 is seen, but that is clumsy and takes unnecessary space in my code. I am looking for a more neat way of doing this.