Swap the First and the Last Character of a String

We are given a string and our task is to swap its first and last character. For example, given the string: s = "hello" after swapping the first and last character, the result will be: "oellh"

Using String Slicing

We can swap the first and last character of a string using slicing and the idea is to extract the middle part of the string and place the last character at the beginning and the first character at the end.

s = "GeeksforGeeks"

# Swap the first and last characters using slicing
if len(s) > 1:
    res = s[-1] + s[1:-1] + s[0]
else:
    res = s  # For strings of length 1 or less, no swap needed

print(res)

seeksforGeekG

Explanation:

• s[-1] + s[1:-1] + s[0] combines the last character, middle part, and first character to swap the first and last characters.
• if len(s) > 1 ensures that the swap only happens if the string has more than one character.
• else: For strings of length 1 or less, no swap is needed, and the string remains unchanged.

Let's understand different method to swap the first and last character of string.

Using List Conversion

In this approach the string is converted into a list the first and last characters are swapped, and the list is then joined back into a string.

s = "GeeksforGeeks"

# Convert string to list and swap first and last characters
a = list(s)
a[0], a[-1] = a[-1], a[0]
res = ''.join(a)
print(res)

seeksforGeekG

Explanation:

• a = list(s) converts the string s to a list of characters.
• a[0], a[-1] = a[-1], a[0] swaps the first and last characters.
• ''.join(a) joins the modified list back into a string.

Using f-strings

In Python f-strings allow for concise and readable string formatting by embedding expressions inside curly braces {}.They are evaluated at runtime, providing an efficient way to manipulate and concatenate strings.

s = "GeeksforGeeks"
res = f"{s[-1]}{s[1:-1]}{s[0]}"
print(res)

seeksforGeekG

Explanation :

• s[-1] accesses the last character of the string s. In this case, it is "s".
• s[1:-1]extracts the middle part of the string, excluding the first and last characters. For the string "GeeksforGeeks", it results in "eeksforGeek".
• s[0] accesses the first character of the string, which is "G".

Using str.join

Using str.join we can swap the first and last characters by combining the last character, middle part and first character into a new string, offering a concise solution.

s = "GeeksforGeeks"
res = ''.join((s[-1], s[1:-1], s[0]))
print(res)

seeksforGeekG

Explanation:

• s[-1] accesses the last character of the string s.
• s[1:-1] extracts the middle part of the string s and excluding the first and last characters.
• s[0] accesses the first character of the string s.
• ''.join(...) combines these parts into a single string without any separator.