I am sure it should be just one line but I am not able to figure out the best to do this:
import numpy as np
import re
arr = np.array(["AB", "AC", "XAB", "XAC", "AD"])
I want to add "X" in the beginning based on a regex match of "^A".
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2 Answers
What about this:
print(np.array(list(map(lambda v: re.sub(r'^A','XA', v) ,arr))))
% outputs: ['XAB' 'XAC' 'XAB' 'XAC' 'XAD']
3 Comments
Kapil Sharma
Thanks a lot! :) I ended up using the regex pattern from @nu11p01n73R instead of "^A"
hpaulj
Using a list comprehension is shorter:
np.array([re.sub('^A','XA',a) for a in arr]). Does arr need to be an array, or return one? This looks like a list of strings problem, not a numpy one.Kapil Sharma
Ohh I see. Yeah - it need not be a numpy array.
You can use the sub function in re module to substitute strings as
>>> import re
>>> str="ABC"
>>> re.sub('^(?=A)','X', str)
'XABC'
^(?=A) is lookahead assertion which matches start postition in anystring that begins with 'A'
2 Comments
Kapil Sharma
Thanks. I combined your and Marcin's solution.
nu11p01n73R
@KapilSharma glad to hear it worked :)