Python

Python Reverse String

A string is an organized chain of characters. To reverse strings, there is no built-in way. If we frequently use strings in the code, we should process the strings in inverse order. Python has different approaches to reverse the string. The functions assigned the slices to make copies of a particular string directly in reverse order. We have to make a reversed order of the selected string.  There are quick and efficient ways to make a reverse copy of an existing string. We are going to explain the following instances of how to reverse strings in Python.

Use of the Slice [] Function

In this method, the string is reversed in slices. To invert a string, we make a slice. The slice begins at the string length, and it usually stops at index 0. We use the slices to slice the string from beginning to end and shift in reverse to the beginning of the string.

For running the Python code, we install spyder 5 software. First, we have to create a new file by pressing “new file” from the menu bar of spyder 5.

We specified no value for beginning and end, which shows the beginning of the index is 0 and the end is “n-1”. In this example, the size is -1 that means the string pursues the end to index at 1st position. The slice function contains three parameters. Those parameters are: start, stop, and step. In this code, we use [::-1]. We didn’t specify the beginning and end here, so the slice will be from the beginning to the end.

The string which we want to reverse is “visual programming”. Let’s run the code by tapping “run” from the menu bar.

The function shows the reversed string. As the output of the original string, we get visual programming and also get the reverse of visual programming by calling the function.

Use “For” Loop

We use for loop to reverse a string. By for loop, there is repetition over elements in the string and addition of each character to the beginning of a new string. In the end, we need the opposite string.

To start the execution of the programs of python, first, we installed spyder5. Then, we have to create a new project by tapping Ctrl+N from the keyboard.

First, we define the function of this program. We declared a new variable “string1” which is used to store the inverted string. Next, we use a for loop that iterates over “string1”. The program executes with the string “visual programming”. We initialize the string, with “visual programming”.

At the end of the code, we called the function to show the value of the inverse string. The variable “string” is passed as an argument of this function.

For running the code, we select the “run” option from the menu bar of spyder5.

Visual programming is printed which is the string’s original value. The reversed value is shown by calling the function.

Use Reversed() and Join() Functions

In this method, we formed the inverted copy of the original string by the use of reversed() and .join(). We use the reversed() function to pass the string, iterate over each character of the string in inverse order, and use the join() method to join the characters. For the implementation of code, we have to install a software named spyder version 5. To write the code, we create a new project by tapping Ctrl+N from the keyboard.

In this code, the function which is defined with the keyword “def” is “rev_a(str)”. The value “str” is passed as an argument to the reversed () function. Inverted characters are joined with the join () function. By using the join() function, we join the reverse object of the original string. A string is a variable in this code. The opposite value of the string is allocated to the “astring”. The function then returns the “astring”.

In the last line, we call the rev_a(str) function which returns the reversed string.

When we tapped F5 to run the code, there were some errors by which the code couldn’t execute. So, we remove the errors then again run the code by pressing F5 from the keyboard. Now, the code is right and it shows the output.

The reversed string ‘gnimmargorp lausiv” is displayed by calling the rev_a(str) function. This function returns the reversed string.

Conclusion

In this article, we have explained several methods with different examples that show how to reverse a string in Python. There is no in-built function that reverses the string in python. But we reverse the string by using the slice method, the use of for loop. We do reverse iteration over characters and use of reversed() function with join() function. We formed the reversed copies of the actual string.

About the author

Kalsoom Bibi

Hello, I am a freelance writer and usually write for Linux and other technology related content