How to convert the following string in python?

Question

Input : UserID/ContactNumber

Output: user-id/contact-number

I have tried the following code:

s ="UserID/ContactNumber"

list = [x for x in s]

for char in list:

     if char != list[0] and char.isupper():
            list[list.index(char)] = '-' + char

 fin_list=''.join((list))
 print(fin_list.lower())

but the output i got is:

  user-i-d/-contact-number

It is generally a bad idea to modify a list as you iterate over it. — FamousJameous
– FamousJameous, Commented Sep 9, 2016 at 14:43
You will have to special case consecutive capital chars. Also note that list(s) gives you a list of characters, and list is a bad name for your own variable. — jonrsharpe
– jonrsharpe, Commented Sep 9, 2016 at 14:45
Even if you are only changing the list, it impairs developer reasoning. In code review I'd suggest list_in and list_out as separate lists even just for developer reasoning alone. — Warren P
– Warren P, Commented Sep 9, 2016 at 14:57

Eugene Yarmash · Accepted Answer · 2016-09-09 14:48:18Z

7

You could use a regular expression with a positive lookbehind assertion:

>>> import re
>>> s  ="UserID/ContactNumber"
>>> re.sub('(?<=[a-z])([A-Z])', r'-\1', s).lower()
'user-id/contact-number'

answered Sep 9, 2016 at 14:48

Eugene Yarmash

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Comments

Xavier C. · Accepted Answer · 2016-09-09 14:55:10Z

2

What about something like that:

s ="UserID/ContactNumber"
so = ''
for counter, char in enumerate(s):
    if counter == 0:
        so = char
    elif char.isupper() and not (s[counter - 1].isupper() or s[counter - 1] == "/"):
        so += '-' + char
    else:
        so += char
print(so.lower())

What did I change from your snippet?

You were checking if this is the first char and if it is a upper char.
I have add a check on the previous char, to not consider when the previous is upper (for the D of ID) or when the previous is \ for the C of Contact.
You are also editing the list list while iterating on it's element, that is dangerous.
I have instead create an output string to store the new values

edited Sep 9, 2016 at 14:55

answered Sep 9, 2016 at 14:45

Xavier C.

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2 Comments

helloV Over a year ago

Instead of giving a new solution, tell what is wrong in his/her logic?

Xavier C. Over a year ago

@helloV, You are totally right, I've edit my answer to explain the change I've made from his/her code

supamaze · Accepted Answer · 2016-09-09 16:15:59Z

-1

I did something like this

s ="UserID/ContactNumber"

new = []
words = s.split("/")

for word in words:
    new_word = ""
    prev = None
    for i in range(0, len(word)):
        if prev is not None and word[i].isupper() and word[i-1].islower():
            new_word = new_word  + "-" + word[i]
            prev = word[i]
            continue
        new_word = new_word  + word[i]
        prev = word[i]
    new.append(new_word.lower())

print "/".join(new)

user-id/contact-number

answered Sep 9, 2016 at 16:15

supamaze

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