Python exercices notebook 2

Problem 1¶

Write a function to calculate the factorial of a number.

In [ ]:

def factorial(n):
    if n == 0:
        return 1
    else:
        return n * factorial(n-1)

print(factorial(5)) # Output: 120

def factorial(n): if n == 0: return 1 else: return n * factorial(n-1) print(factorial(5)) # Output: 120

Problem 2¶

Write a function that takes two lists and returns True if they have at least one common member.

In [ ]:

def common_member(a, b):
    for i in a:
        for j in b:
            if i == j:
                return True
    return False

a = [1, 2, 3, 4, 5]
b = [5, 6, 7, 8, 9]
print(common_member(a, b)) # Output: True

def common_member(a, b): for i in a: for j in b: if i == j: return True return False a = [1, 2, 3, 4, 5] b = [5, 6, 7, 8, 9] print(common_member(a, b)) # Output: True

Problem 3¶

Write a function that takes a string and returns the first non-repeated character in the string.

In [ ]:

def first_non_repeated_character(string):
    char_count = {}
    for i in string:
        if i in char_count:
            char_count[i] += 1
        else:
            char_count[i] = 1
    for i in string:
        if char_count[i] == 1:
            return i
    return None

string = 'abcdefghijklmnopqrstuvwxyzbcdefghijklmnopqrstuvwxyz'
print(first_non_repeated_character(string)) # Output: 'a'

def first_non_repeated_character(string): char_count = {} for i in string: if i in char_count: char_count[i] += 1 else: char_count[i] = 1 for i in string: if char_count[i] == 1: return i return None string = 'abcdefghijklmnopqrstuvwxyzbcdefghijklmnopqrstuvwxyz' print(first_non_repeated_character(string)) # Output: 'a'

a

Problem 4¶

Write a Python function that takes two strings and returns True if the first string is a substring of the second string, and False otherwise.

In [ ]:

def is_substring(s1, s2):
    return s1 in s2

print(is_substring("hello", "hello world"))

def is_substring(s1, s2): return s1 in s2 print(is_substring("hello", "hello world"))

Problem 5¶

Write a Python program to find the sum of the digits of a number.

In [ ]:

def sum_of_digits(number):
    return sum(int(digit) for digit in str(number))

print(sum_of_digits(123))

def sum_of_digits(number): return sum(int(digit) for digit in str(number)) print(sum_of_digits(123))

Problem 6¶

Write a Python program to find the longest word in a list of words.

In [ ]:

def find_longest_word(words):
    return max(words, key=len)

print(find_longest_word(["apple", "banana", "cherry"]))

def find_longest_word(words): return max(words, key=len) print(find_longest_word(["apple", "banana", "cherry"]))

Problem 7¶

Write a Python program to sort a list of dictionaries by a given key.

In [ ]:

def sort_dict_list(dict_list, key):
    return sorted(dict_list, key=lambda x: x[key])

dict_list = [{"name": "John", "age": 25}, {"name": "Jane", "age": 22}, {"name": "Jim", "age": 30}]
print(sort_dict_list(dict_list, "age"))

def sort_dict_list(dict_list, key): return sorted(dict_list, key=lambda x: x[key]) dict_list = [{"name": "John", "age": 25}, {"name": "Jane", "age": 22}, {"name": "Jim", "age": 30}] print(sort_dict_list(dict_list, "age"))

[{'name': 'Jane', 'age': 22}, {'name': 'John', 'age': 25}, {'name': 'Jim', 'age': 30}]

Problem 8¶

Write a Python program to find the frequency of each word in a string.

In [ ]:

def word_frequency(string):
    #splitting my sentence into words 
    words = string.split()
    #print(words)
    word_count = {}
    for word in words:
        if word in word_count:
            word_count[word] += 1
        else:
            word_count[word] = 1
    return word_count

string = "the quick brown the fox jumps over the lazy dog"
dic = word_frequency(string)
dic["fox"]

def word_frequency(string): #splitting my sentence into words words = string.split() #print(words) word_count = {} for word in words: if word in word_count: word_count[word] += 1 else: word_count[word] = 1 return word_count string = "the quick brown the fox jumps over the lazy dog" dic = word_frequency(string) dic["fox"]

Out[ ]:

1

Problem 9¶

Write a Python program to find the prime numbers in a given range.

In [ ]:

def prime_numbers(start, end):
    prime_list = []
    for number in range(start, end + 1):
        for i in range(2, number):
            if number % i == 0:
                break
        else:
            prime_list.append(number)
    return prime_list

print(prime_numbers(2, 20))

def prime_numbers(start, end): prime_list = [] for number in range(start, end + 1): for i in range(2, number): if number % i == 0: break else: prime_list.append(number) return prime_list print(prime_numbers(2, 20))

[2, 3, 5, 7, 11, 13, 17, 19]

In [ ]: