Learn the best ways to reverse a string when coding in Python
This article was co-authored by wikiHow staff writer, Kyle Smith. Kyle Smith is a wikiHow Technology Writer, learning and sharing information about the latest technology. He has presented his research at multiple engineering conferences and is the writer and editor of hundreds of online electronics repair guides. Kyle received a BS in Industrial Engineering from Cal Poly, San Luis Obispo.
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Trying to reverse a string in Python? There are several easy ways to do so! You can use the slice function to reverse the string in 1 line of code. Alternatively, use a For loop or the reversed() function for additional flexibility in the reversal process. You can also use the join() function or a list to make a string backwards. This wikiHow guide shows 6 tricks to reverse a string in Python.
Things You Should Know
- Using a slice is the quickest, simplest way to reverse a string.
- Use a For loop if you need more customization in the reversal process.
- Try the reversed() function to create a reversed iterable object from the string.
Steps
Using a Slice
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1Assign the string to a variable. Python, the easy-to-learn programming language, has several methods for working with strings. This method uses the slice function to reverse the string. Open your Python file or start a new one. Then use the assignment operator = to assign the string you want to reverse to a variable. For example:
- a = "example string"
-
2Type [::-1] after the string. This is a slice statement that begins at the end of the string, ends at the beginning of the string (position 0), and steps by 1 backwards through the string (indicated by the negative 1). Following our example:[1]
- a = "example string"[::-1]
Advertisement -
3Print the string. The string assigned to a has been reversed by the slice. To see the reversed string, use the print() function:
- print(a)
- For our example, “gnirts elpmaxe” would print in the terminal.
Creating a Slice Function
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1Assign the string to a variable. This method creates a function that uses a slice to reverse the string. Use the assignment operator = to assign the string you want to reverse to a variable. For example:
- f = "example string"
-
2Create the custom string reversing function. This function will return a reversed string.
- def backwards(text):
return text[::-1]
- def backwards(text):
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3Use the function. You can now apply this function to any string that you want to reverse. Following our example:
- f_reverse = backwards(f)
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4Print the string. The string assigned to f has been reversed by the new function. To see the reversed string f_reverse, use the print() function:
- print(f_reverse)
- For our example, “gnirts elpmaxe” would print in the terminal.
Using a For Loop
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1Assign the string to a variable. This method creates a loop to reverse the string. Use the assignment operator = to assign the string you want to reverse to a variable. For example:
- b = "example string"
- You can convert an integer to a string if needed.
-
2Create a blank string variable. This method will append the characters in the original string backwards to a new blank variable. To create a blank variable, assign a new variable to "". For example:
- b_reverse = ""
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3Make a For loop to reverse the string. This For loop will iterate through the original string, appending each letter to the beginning of the new variable. This will reverse the string. Continuing our example:
- for i in b:
b_reverse = i + b_reverse
- for i in b:
-
4Print the string. The string assigned to b has been reversed by the For loop. To see the reversed string b_reverse, use the print() function:
- print(b_reverse)
- For our example, “gnirts elpmaxe” would print in the terminal.
Using reversed()
-
1Assign the string to a variable. There are many functions to learn, especially if you’ve just started programming in Python. This method uses the reversed() function to reverse the string. Use the assignment operator = to assign the string you want to reverse to a variable. For example:
- c = "example string"
-
2Use the reversed() function to reverse the string. This function reverses the order of an iterable object, like a string. To use the reverse function, create a new variable assigned to the reversed original string:[2]
- c_backward = reversed(c)
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3Create a new blank string variable. This new variable will be used to create the reversed string. The reversed function doesn’t return a string, so a new string variable is needed.
- c_new = ""
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4Make a For loop to create the reversed string. This loop will append the reversed list of characters to the new string variable c_new.
- for i in c_backward:
c_new = c_new + i
- for i in c_backward:
-
5Print the string. The string assigned to c has been reversed by the reversed() function and For loop. To see the reversed string c_new, use the print() function:
- print(c_new)
- For our example, “gnirts elpmaxe” would print in the terminal.
Using join()
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1Assign the string to a variable. This method uses the join() and reverse() to reverse the string. Use the assignment operator = to assign the string you want to reverse to a variable. For example:
- e = "example string"
-
2Use join() and reverse() to reverse the string. The reverse() function reverses all of the items in the string and turns it into an iterator type. Then, the join() function combines the items into one string. Following our example, the code is written:
- e_reverse = "".join(reversed(e))
-
3Print the string. The string assigned to {{kbd|e} has been reversed by the reversed() and join() function. To see the reversed string e_reverse, use the print() function:
- print(e_reverse)
- For our example, “gnirts elpmaxe” would print in the terminal.
Using a List
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1Assign the string to a variable. This method uses a list to reverse the string. Use the assignment operator = to assign the string you want to reverse to a variable. For example:
- d = "example string"
-
2Create an empty list variable by using square brackets. This list will contain the individual characters in the string.
- letter_list = []
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3Create an empty string variable by using quotation marks. This string will be where the characters are placed in reverse order.
- d_reverse = ""
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4Write a for loop that adds each character in the string to the list. You can use the append() function to do so:
- for j in d:
letter_list.append(j)
- for j in d:
-
5Write a for loop that adds each character in the list to the new string variable. Use the plus (+) operator to do so. Place the iterator first and the reverse string variable second to add each character to the front of the string.
- for k in letter_list:
d_reverse = k + d_reverse
- for k in letter_list:
-
6Print the string. The string assigned to d has been reversed by the list and For loops. To see the reversed string d_reverse, use the print() function:
- print(d_reverse)
- For our example, “gnirts elpmaxe” would print in the terminal.