﻿ Python Exercise: Reverse a string - w3resource

Python Exercise: Reverse a string

Python Functions: Exercise-4 with Solution

Write a Python program to reverse a string.

Sample String: "1234abcd"
Expected Output: "dcba4321"

Sample Solution-1:

Python Code:

``````# Define a function named 'string_reverse' that takes a string 'str1' as input
def string_reverse(str1):
# Initialize an empty string 'rstr1' to store the reversed string
rstr1 = ''

# Calculate the length of the input string 'str1'
index = len(str1)

# Execute a while loop until 'index' becomes 0
while index > 0:
# Concatenate the character at index - 1 of 'str1' to 'rstr1'
rstr1 += str1[index - 1]

# Decrement the 'index' by 1 for the next iteration
index = index - 1

# Return the reversed string stored in 'rstr1'
return rstr1

# Print the result of calling the 'string_reverse' function with the input string '1234abcd'
print(string_reverse('1234abcd'))
```
```

Sample Output:

```dcba4321
```

Explanation:

In the exercise above the code defines a function named "string_reverse()" that takes a string as input and returns its reversed version using a while loop and string manipulation. The final print statement demonstrates the result of calling the "string_reverse()" function with the input string '1234abcd'.

Pictorial presentation:

Flowchart:

Sample Solution-2:

Python Code:

``````# Define a function named 'reverse' that takes an iterable 'itr' as input and returns its reverse
def reverse(itr):
# Using slicing with [::-1] reverses the input 'itr' and returns the reversed version
return itr[::-1]

# Initialize a string variable 'str1' with the value '1234abcd'
str1 = '1234abcd'

# Print the original string 'str1'
print("Original string:", str1)

# Print the reversed string obtained by calling the 'reverse' function with the string '1234abcd'
print("Reverse string:", reverse('1234abcd'))

# Change the value of 'str1' to 'reverse'
str1 = 'reverse'

# Print the original string 'str1'
print("\nOriginal string:", str1)

# Print the reversed string obtained by calling the 'reverse' function with the string 'reverse'
print("Reverse string:", reverse(str1))
```
```

Sample Output:

```Original string: 1234abcd
Reverse strig: dcba4321

Original string: reverse
Reverse string: esrever
```

Explanation:

In the exercise above the code demonstrates the use of a "reverse()" function that utilizes slicing ([::-1]) to reverse a given input iterable. It then applies this function to reverse both the string '1234abcd' and the string 'reverse' and prints their original and reversed versions.

Flowchart:

Python Code Editor:

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