python string manipulation to match windows firewall syntax

Question

I have a string like so:

string = "27.116.56.0 27.116.59.255 43.230.209.0 43.230.209.255"  #(white space sep)

how would you go from it to this format:

string = "27.116.56.0-27.116.59.255,43.230.209.0-43.230.209.255"

**the string will have unknown length , the elements number will allways be even.

I've looked at some close examples and got confused.. what is the best easy way doing that?

Don't name your variables `string` as it will stomp on the `string` module — pault, Sep 20 '18 at 18:22
the string will have unknown length , the elements number will even. — Avarage_joe, Sep 20 '18 at 18:35
Does this answer your question? [Iterate an iterator by chunks (of n) in Python?](https://stackoverflow.com/questions/8991506/iterate-an-iterator-by-chunks-of-n-in-python) — yivi, Nov 30 '21 at 05:58

TheoretiCAL · Answer 1 · 2018-09-20T20:06:43.667

2

# Create a new list containing the ips
str_elems = "27.116.56.0 27.116.59.255 43.230.209.0 43.230.209.255".split()
# Use a format string to build the new representation, where each list element is assigned a spot in the string
# We use the * operator to convert the single list into multiple arguments for the format
new_str = ("{}-{},"*(len(str_elems)/2)).format(*str_elems).rstrip(',')

edited Sep 20 '18 at 20:06

answered Sep 20 '18 at 18:22

TheoretiCAL

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@TheoretiCAL the string will have unknown length , the elements number will allways be even. – Avarage_joe Sep 20 '18 at 19:42
@Avarage_joe I've updated it to support unknown length. – TheoretiCAL Sep 20 '18 at 20:07

score 1 · Accepted Answer · answered Sep 20 '18 at 18:26

For a general solution, you can iterate over your split string in chunks of 2.

s = "27.116.56.0 27.116.59.255 43.230.209.0 43.230.209.255".split()
print(",".join(["-".join(s[i:i + 2]) for i in range(0, len(s), 2)]))
#'27.116.56.0-27.116.59.255,43.230.209.0-43.230.209.255'

Join the inner chunks with a "-" and finally join the whole thing with ","

score 0 · Answer 3 · answered Sep 20 '18 at 22:56

string = "27.116.56.0 27.116.59.255 43.230.209.0 43.230.209.255"

ip_list = string.split(" ")                     # split the string to a list using space seperator

for i in range(len(ip_list)):                   # len(ip_list) returns the number of items in the list (4)
                                                # range(4) resolved to 0, 1, 2, 3 

    if (i % 2 == 0): ip_list[i] += "-"          # if i is even number - concatenate hyphen to the current IP string 
    else: ip_list[i] += ","                     # otherwize concatenate comma

print("".join(ip_list)[:-1])                    # "".join(ip_list) - join the list back to a string
                                                # [:-1] trims the last character of the result (the extra comma)

python string manipulation to match windows firewall syntax

3 Answers3