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Posts Tagged ‘slice’
Reverse a string
September 23, 2010
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Exercise #1: Take a string and reverse its characters. For instance “ab12” => “21ba”.
Solution:
#!/usr/bin/env python s = 'Python adventures' print s # Python adventures print s[::-1] # serutnevda nohtyP
Slice notation has the form [start:stop:step]. By default, start is at the beginning of a sequence, stop is at the end, and step is 1. So the slice [::-1] returns the full sequence in reverse order.
Exercise #2: Decide if a word is a palindrome.
Solution:
#!/usr/bin/env python
def is_palindrome(str):
return str == str[::-1]
print is_palindrome('1367631') # True
print is_palindrome('Python') # False
Python Adventures 