Best way to loop over a python string backwards

Question

What is the best way to loop over a python string backwards?

The following seems a little awkward for all the need of -1 offset:

string = \"trick or          


        

Answer 1

string reverse

def reverse(a_string):
    rev = ''
    for i in range(len(a_string)-1, -1, -1):
        rev = rev + a_string[i]
    return rev
print(reverse("This string should be reversed!"))

output is: !desrever eb dluohs gnirts sihT

Answer 2

 string = "trick or treat"
 for c in string[::-1]:
     print c

I would use that. It is probably quite fast although there may be a slightly better way (but I doubt it).

EDIT: Actually, with a second test using a program I hacked together, reversed is probably the way to go.

 ==== Results ====
Sample 1: 0.0225071907043 # Using a for loop
Sample 2: 0.0100858211517 # Using reversed

Answer 3

def reverse(text):
    x = ""
    for i in range(len(text)):
        x = x + text[len(text)-i-1]
    return x

Answer 4

Reverse a String in Python using For Loop

outputStr = ''
a = raw_input("Enter String: ")
for i in range(len(a), 0, -1):
    outputStr += a[i-1]
print outputStr

Answer 5

string = "trick or treat"
for c in reversed(string):
    print c

Will do what I think you want. It uses an iterator. This should work with anything that has __reveresed__() or __len__() and __getitem__() implemented. __getitem__() would have to take int arguments starting at 0.

Answer 6

Here is a way to reverse a string without utilizing the built in features such as reversed. Negative step values traverse backwards.

def reverse(text):
    rev = ''
    for i in range(len(text), 0, -1):
        rev += text[i-1]
    return rev