Question

I want to split a string like:

strg = "22+11-aa+bb-44-" 

into a list like this:

my_list = ['22', '+','11', '-', 'aa', '+', 'bb', '-44', '-']

All the non-digit elements are totally split out, if the element after ‘-‘ is made of digits, then it should join together with the ‘-‘ and become a negative number.

Answer 1

A solution without regexs that makes it longer, but faster on the large data sets:

strg="22+11-aa+bb-44-"
arr=[]
i=0
for j in range(len(strg)):
        if strg[j] in '+-':
            arr.append(strg[i:j])
            if strg[j]=='-' and strg[min(j+1,len(strg)-1)].isdigit():
                i=j
            else:
                arr.append(strg[j])
                i=j+1
print arr

result:

['22', '+', '11', '-', 'aa', '+', 'bb', '-44', '-']