In the previous section we discussed the basics of Python Strings. Now let us take a look at some real-life application Problems.
1. Reverse a String
Write a program to reverse a given string without using built-in reverse functions.
s = input("Enter a string: ")
rev = ""
for ch in s:
rev = ch + rev
print("Reversed string:", rev)
Enter a string: qubrica
Reversed string: acirbuq
| Iteration | Character (ch) | Operation (ch + rev) | Value of rev |
|---|---|---|---|
| Start | - | - | - |
| 1 | 'q' | 'q' + " " | q |
| 2 | 'u' | 'u' + "q" | uq |
| 3 | 'b' | 'b' + "uq" | buq |
| 4 | 'r' | 'r' + "buq" | rbuq |
| 5 | 'i' | 'i' + "rbuq" | irbuq |
| 6 | 'c' | 'c' + "irbuq" | cirbuq |
| 7 | 'a' | 'a' + "cirbuq" | acirbuq |
2. String Concatenation
Write a Python Program to concatenate two Strings.
s1 = input("Enter first string: ")
s2 = input("Enter second string: ")
result = s1 + s2
print("Concatenated String:", result)
# Enter first string: python
# Enter second string: programming
# Concatenated String: pythonprogramming
3. String Length
Write a Python Program to find the string length without using a built in function.
s = input("Enter a string: ")
count = 0
for ch in s:
count = count + 1
print("Length of the string is:", count)
# Enter a string: qubrica
# Length of the string is: 7
4. Largest Word in a Sentence
Write a Program to find Largest word in a Sentence
s = input("Enter a sentence: ")
words = s.split()
longest = words[0]
for word in words:
if len(word) > len(longest):
longest = word
print("Longest word:", longest)
# Enter a sentence: python programming is easy
# Longest word: programming
5. Convert Uppercase to Lowercase (Without built-in function)
Write a Python Program to convert Uppercase letters to Lowercase
s = input("Enter a string: ")
result = ""
for ch in s:
if 'A' <= ch <= 'Z':
result += chr(ord(ch) + 32)
else:
result += ch
print("Converted string:", result)
# Enter a string: PYTHON
# Converted string: python
6. Anagram
Write a program to check if two strings are anagrams or not.
(An anagram is a word formed by rearranging the letters of a different word)
listen = silent
s1 = input("Enter first string: ")
s2 = input("Enter second string: ")
if sorted(s1) == sorted(s2):
print("Anagram")
else:
print("Not Anagram")
# Enter first string: listen
# Enter second string: silent
# Anagram
7. Count Digits, Letters and Special Characters
Write a Python Program to count how many digits, alphabets and special characters exist.
s = input("Enter a string: ")
letters = digits = special = 0
for ch in s:
if ch.isalpha():
letters += 1
elif ch.isdigit():
digits += 1
else:
special += 1
print("Letters:", letters)
print("Digits:", digits)
print("Special Characters:", special)
# Enter a string: strings123@
# Letters: 7
# Digits: 3
# Special Characters: 1
8. Remove Space from String
Write a C program to remove all spaces from the string.
s = input("Enter a string: ")
result = ""
for ch in s:
if ch != " ":
result += ch
print("String without spaces:", result)
# Enter a string: Python Programming
# String without spaces: PythonProgramming
9. Count Vowels and Consonants
Write a Python Program to count the number of vowels and consonants in a string.
s = input("Enter a string: ").lower()
vowels = "aeiou"
v = c = 0
for ch in s:
if ch.isalpha():
if ch in vowels:
v += 1
else:
c += 1
print("Vowels:", v)
print("Consonants:", c)
# Enter a string: Aeroplane
# Vowels: 5
# Consonants: 4