String Programs in Python

 1.Write a program to reverse a string.

def reverse_string(s):
    return s[::-1]

string = "hello"
print(reverse_string(string))

2. Write a program to check if a string is a palindrome.

def is_palindrome(s):
    return s == s[::-1]

string = "madam"
print(is_palindrome(string))

3.Write a program to count the number of vowels and consonants in a string.

def count_vowels_consonants(s):
    vowels = "aeiouAEIOU"
    v_count = c_count = 0
    for char in s:
        if char.isalpha():
            if char in vowels:
                v_count += 1
            else:
                c_count += 1        
            return v_count, c_count

string = "hello"
vowels, consonants = count_vowels_consonants(string)
print(f"Vowels: {vowels}, Consonants: {consonants}") 

4.  Write a program to remove duplicate characters from a string.

def remove_duplicates(s):
    result = ""
    for char in s:
        if char not in result:
            result += char
    return result

string = "programming"
print(remove_duplicates(string)) 

5.  Write a program to count the frequency of each character in a string.

from collections import Counter

def char_frequency(s):
    return dict(Counter(s))

string = "hello"
print(char_frequency(string)) 

6. Write a program to check if two strings are anagrams.

def are_anagrams(s1, s2):
    return sorted(s1) == sorted(s2)

string1 = "listen"
string2 = "silent"
print(are_anagrams(string1, string2)) 

7.  Write a program to find the longest word in a sentence.

def longest_word(sentence):
    words = sentence.split()
    return max(words, key=len)

sentence = "I love programming in Python"
print(longest_word(sentence))

8.  Write a program to capitalize the first and last character of each word in a string.

def capitalize_first_last(s):
    words = s.split()
    result = []
    for word in words:
        if len(word) > 1:
            word = word[0].upper() + word[1:-1] + word[-1].upper()
        else:
            word = word.upper()
        result.append(word)
    return " ".join(result)

string = "hello world"
print(capitalize_first_last(string)) 

 9. Write a program to replace all occurrences of a substring in a string.

def replace_substring(s, old, new):
    return s.replace(old, new)

string = "hello world"
print(replace_substring(string, "world", "there")) 

10.  Write a program to find all possible substrings of a string.

def all_substrings(s):
    substrings = []
    for i in range(len(s)):
        for j in range(i + 1, len(s) + 1):
            substrings.append(s[i:j])
        return substrings

string = "abc"
print(all_substrings(string))