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Python

Posted by Derek Derek
Derek Derek
8,744 Points

Python list - separate elements by odd/even index

Hello,

I am trying to solve a question in python that goes like this:

You are given a string, for example, "abcdefg"

and you want to output

a c e g

bdf

Note that there is a space in between each letters in the first output.

How would you write it in python?

My attempt was to create two lists and add to them depending on each letter's index using modulo 2. But I am getting errors..

def separate_string(sentence):
    l = list(sentence)
    l2 = list()
    for letter in range(l):
        index = l.index(letter)
        if index % 2 != 0:
            l2.append(l[letter])
            l.remove(letter)



separate_string('abcedfg')

Thank you for your help!

1 Answer

Quentin Durantay
Quentin Durantay
17,880 Points

Hi,

I think your code would be clearer if you use different lists and strings for all your needs. Also, I would prefer to use a count variable here for index and not use range, as it's easier to loop through the initial list, and not its range. Also, don't use index as it will break if you have repetition of letters in your sentence, as index returns the first occurence of the letter only.

Try this instead for example:

def separate_string(sentence):
    l = list(sentence)
    list_even = list()
    list_odd = list()
    index = 0

    for letter in l:
        if index % 2 != 0:
            list_even.append(letter)
        else:
            list_odd.append(letter)
        index += 1

    string_even = "".join(list_even)
    string_odd = " ".join(list_odd)

    print(string_odd)
    print(string_even)


separate_string('abcdefg')