Removing digits from each line of a file

I wish to write a code in Python which reads each line from a txt and whilst doing so takes each digit from that sentence and stores it in an array. Simultaneously, takes that new word and stores that one in another array.

I have been trying permutation of the following code:

while True:    content=file.readline()print (re.sub(pattern, '', content.file.readline())

with no success (Yes I do not have the array specified!! But if this loop does not work, what is the point of appending the content to an array?)