In Python, strings are ordered sequences of character data.
There is no built-in method to reverse a string. However, strings can be reversed in several different ways.
Three methods to reverse a string are explained below:
Strings can be reversed using slicing. To reverse a string, we simply create a slice that starts with the length of the string, and ends at index 0.
To reverse a string using slicing, write:
stringname[stringlength::-1] # method 1
Or write without specifying the length of the string:
stringname[::-1] # method2
The slice statement means start at string length, end at position 0, move with the step -1 (or one step backward).
s="Python" # initial string stringlength=len(s) # calculate length of the list slicedString=s[stringlength::-1] # slicing print (slicedString) # print the reversed string
To start, let’s create a new array called
We can then loop over the list with iterating variable
index initialized with the length of the list.
We then simply keep iterating until the index is less than zero.
s = "Python" # initial string reversedString= index = len(s) # calculate length of string and save in index while index > 0: reversedString += s[ index - 1 ] # save the value of str[index-1] in reverseString index = index - 1 # decrement index print(reversedString) # reversed string
This is a powerful technique that takes advantage of Python’s iterator protocol. This technique reverses a string using reverse iteration with the
reversed() built-in function to cycle through the elements in the string in reverse order and then use
.join() method to merge all of the characters resulting from the reversed iteration into a new string.
The general syntax is
The following Python code demonstrates the concept.
s = 'Python' #initial string reversed=''.join(reversed(s)) # .join() method merges all of the characters resulting from the reversed iteration into a new string print(reversed) #print the reversed string
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