CODEWITHSUNDEEP
python-2.7functionloops
Addison
Addison

Reputation: 423

I am trying to create a reverse function in python 2.7

I am getting 'none' as my output rather than the reversed string. I am not sure if I am printing the wrong thing. I am relatively new to loops, so bear with me, but the basic goal is to reverse 'old_string'

 old_string=("I am testing") #Defining old_string


 def reverse(old_string):

     rng=range((len(old_string))-1,11,1) #rng= the range of the number of index values in old_string, starting with max-1 ending at 0 by steps of -1
     new_string='' #New string equals the following loop

     for index in rng: #For index in the above range


         new_string=new_string,old_string[index] #New string equals itself PLUS the origninal old string using index values of 'index'
         return new_string


 print reverse(old_string)

Upvotes: 0

Views: 58

Answers (3)

Addison
Addison

Reputation: 423

My return statement was inside the for loop, thus ending the loop. So, I moved it out of the loop, so now it is done when the loop is completely finished. (Also I fixed the range numbers)

Upvotes: 0

bfleek
bfleek

Reputation: 11

By placing the return statement in the for loop you are exiting the function before the for loop has finished. You need to put the return statement outside of the for loop.

Also if you just want to reverse the string you can do the following

>>> 'hello world'[::-1] 'dlrow olleh'

Upvotes: 1

Keiwan
Keiwan

Reputation: 8291

These are the errors in your version:

def reverse(old_string):
    rng=range((len(old_string))-1,-1,-1) # this is the correct range that you want
    new_string='' 

    for index in rng:
        new_string += old_string[index] # concatenate strings with + (or +=)

    return new_string   # return outside of your loop

By the way, you can always just reverse a string s with 

s[::-1]

Upvotes: 1

Related Questions