Reverse a string in Python

Question

There is no built in reverse function for Python\'s str object. What is the best way of implementing this method?

If supplying a very conci

Answer 1

Sure, in Python you can do very fancy 1-line stuff. :)
Here's a simple, all rounder solution that could work in any programming language.

def reverse_string(phrase):
    reversed = ""
    length = len(phrase)
    for i in range(length):
        reversed += phrase[length-1-i]
    return reversed

phrase = raw_input("Provide a string: ")
print reverse_string(phrase)

Answer 2

This is also an interesting way:

def reverse_words_1(s):
    rev = ''
    for i in range(len(s)):
        j = ~i  # equivalent to j = -(i + 1)
        rev += s[j]
    return rev

or similar:

def reverse_words_2(s):
    rev = ''
    for i in reversed(range(len(s)):
        rev += s[i]
    return rev

Another more 'exotic' way using byterarray which supports .reverse()

b = bytearray('Reverse this!', 'UTF-8')
b.reverse()
b.decode('UTF-8')

will produce:

'!siht esreveR'

Answer 3

@Paolo's s[::-1] is fastest; a slower approach (maybe more readable, but that's debatable) is ''.join(reversed(s)).

Answer 4

This is simple and meaningful reverse function, easy to understand and code

def reverse_sentence(text):
    words = text.split(" ")
    reverse =""
    for word in reversed(words):
        reverse += word+ " "
    return reverse

Answer 5

Here is a no fancy one:

def reverse(text):
    r_text = ''
    index = len(text) - 1

    while index >= 0:
        r_text += text[index] #string canbe concatenated
        index -= 1

    return r_text

print reverse("hello, world!")

Answer 6

Recursive method:

def reverse(s): return s[0] if len(s)==1 else s[len(s)-1] + reverse(s[0:len(s)-1])

example:

print(reverse("Hello!"))    #!olleH