从列表 python 中删除非数值

Question

How to do I go about removing non numerics from a list such as;

['$1,500 / month ', '$2,200 / month ', '$1,200 / month ']

to result in the following;

['1500', '2200', '1200']

I've found various samples of code but nothing is working for me.

Answer 1

You could use a list comprehension with a regular expression to replace all non numeric characters:

>>> import re
>>> lst = ['$1,500 / month ', '$2,200 / month ', '$1,200 / month ']
>>> lst
['$1,500 / month ', '$2,200 / month ', '$1,200 / month ']
>>> new_lst = [re.sub("[^0-9]", "", s) for s in lst]
>>> new_lst
['1500', '2200', '1200']

Or alternatively, use str. in a similar fashion along with str. :

>>> lst = ['$1,500 / month ', '$2,200 / month ', '$1,200 / month ']
>>> lst
['$1,500 / month ', '$2,200 / month ', '$1,200 / month ']
>>> new_lst = [''.join(ch for ch in s if ch.isdigit()) for s in lst]
>>> new_lst
['1500', '2200', '1200']

Answer 2

Tokenize so that you only have the number string.
Tokenize by the comma, call the result tokens.
Set output = 0
For each token in tokens:
    multiply output by 1000
    parse token, call the result newnum
    add newnum to output
return output

Some functions to look into:

• string.split(delim) will tokenize a string by the given delimiter.
• int(string) will parse a string into an integer
• float(string) will parse a string into a floating point number.

Edit: Oh, this is wrong - this would return the numeric value of each value in the list. Though, technically, you could just return string(output) for the string version