CODEWITHSUNDEEP
pythonpython-3.xpython-3.4
Hello World
Hello World

Reputation: 63

Reverse function not working properly

I created my own function to reverse the words in a phrase such as:

reverse("Hello my name is Bob")
Bob is name my Hello

This is the code that I have

def first_word(string):
    first_space_pos = string.find(" ")
    word = string[0:first_space_pos]
    return word

def last_words(string):
    first_space_pos = string.find(" ")
    words = string[first_space_pos+1:]
    return words

def reverse(string):
    words = string.count(" ") +1
    count = 1
    string_reversed = ""
    while count <= words:
        string_reversed = first_word(string) + str(" ") + string_reversed
        string = last_words(string)
        count += 1
    return string_reversed

Whenever I enter a string, the last letter of the first word of the phrase always gets cut off

reverse("Hello my name is Bob")
Bob is name my Hell

The "o" is missing in Hello. Where did I go wrong?

Upvotes: 2

Views: 158

Answers (4)

zehnpaard
zehnpaard

Reputation: 6233

Your issue is with this code:

def first_word(string):
    first_space_pos = string.find(" ")
    word = string[0:first_space_pos]
    return word

When you get to the iteration of your loop in the reverse function, you are sending a string without any spaces (because your string consists of the final word to be processed), so string.find(" ") is returning -1. Easiest solution is to replace it with the below:

def first_word(string):
    first_space_pos = string.find(" ")
    if first_space_pos == -1:
        first_space_pos = len(string)
    word = string[0:first_space_pos]
    return word

(This is assuming that you have to modify and use the functions above - other answers provide better ways to implement the functionality)

Upvotes: 1

AbtPst
AbtPst

Reputation: 8018

you need to modify your loop slightly

def reverse(string):
words = string.count(" ") +1
count = 1
string_reversed = ""

while count < words:

    string_reversed = first_word(string) + str(" ") + string_reversed

    string = last_words(string)

    count += 1

print(string + " " + string_reversed)
return string + " " + string_reversed

Upvotes: 1

lord63. j
lord63. j

Reputation: 4670

Although you can use [::-1] to get a reversed list, you can also use reversed, cause it's more readable and explicit.

>>> words = "Hello my name is Bob"
>>> ' '.join(reversed(words.split(' ')))
'Bob is name my Hello'

Upvotes: 2

Avinash Raj
Avinash Raj

Reputation: 174786

Keep it simple,

>>> ' '.join("Hello my name is Bob".split()[::-1])
'Bob is name my Hello'

OR

>>> l = "Hello my name is Bob".split()[::-1]
>>> s = ""
>>> for i,j in enumerate(l):
    if i != 0:
        s += ' ' + j
    else:
        s += j


>>> s
'Bob is name my Hello'
>>>

Upvotes: 1

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