Python reverse list [duplicate]

Answer 1

For future reference when an object has a method like [].reverse() it generally performs that action o n the object (ie. the list is sorted and returns nothing, None) in contrast to built in functions like sorted which perform an action on an object and returns a value (ie the sorted list)

Answer 2

The for loop iterates the string from end (last letter) to start (first letter)

>>> s = 'You can try this too :]'
>>> rev = ''
>>> for i in range(len(s) - 1, -1, -1):
...     rev += s[i]
>>> rev
']: oot siht yrt nac uoY'

Answer 3

Based on comments and other answers:

str_a = 'this is a string'
rev_word = ' '.join(reversed(str_a.split()))

Method chaining does work in Python after all...

Answer 4

Various reversals on a string:

instring = 'This is a string'
reversedstring = instring[::-1]
print reversedstring        # gnirts a si sihT
wordsreversed = ' '.join(word[::-1] for word in instring.split())
print wordsreversed         # sihT si a gnirts
revwordorder = ' '.join(word for word in instring.split()[::-1])
print revwordorder          # string a is This
revwordandorder = ' '.join(word[::-1] for word in instring.split()[::-1])
print revwordandorder       # gnirts a si sihT

Answer 5

>>> s = 'this is a string'
>>> s[::-1]
'gnirts a si siht'
>>> ''.join(reversed(s))
'gnirts a si siht'

Answer 6

.reverse() returns None. Therefore you should not be assigning it to a variable.

Use this instead:

stra = 'This is a string'
revword = stra.split()
revword.reverse()
revword=''.join(revword)

I've run the code on IDEOne for you so you can see the output. (Also notice that the output is stringaisThis; you may want to use ' '.join(revword), with a space, instead.)

Also note that the method you have provided only reverses the words, not the text. @ron.rothman provided a link that does detail how to reverse a string in its entirety.