100 python exercises (6)

The following is a code example for questions 61 to 70:

61. Write a program that determines whether a string is a palindrome (same for both forward and reverse spellings).

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

string = input("请输入一个字符串：")

if is_palindrome(string):
    print("是回文串")
else:
    print("不是回文串")

62. Write a program to find the most frequent element in a list.

from collections import Counter

num_list = [1, 2, 3, 4, 2, 2, 3, 4, 4, 4]

counter = Counter(num_list)

most_common = counter.most_common(1)

print("出现频率最高的元素是：", most_common[0][0])

63. Write a program to find the common elements in two lists.

list1 = [1, 2, 3, 4, 5]
list2 = [4, 5, 6, 7, 8]

common_elements = list(set(list1) & set(list2))

print("两个列表中的公共元素为：", common_elements)

64. Write a program that calculates the average of all odd numbers in a list.

num_list = [1, 2, 3, 4, 5, 6, 7, 8, 9]

odd_numbers = [num for num in num_list if num % 2 != 0]

average = sum(odd_numbers) / len(odd_numbers)

print("所有奇数的平均值为：", average)

65. Write a program to determine whether a year is a leap year.

def is_leap_year(year):
    if year % 400 == 0:
        return True
    elif year % 100 == 0:
        return False
    elif year % 4 == 0:
        return True
    else:
        return False

year = int(input("请输入一个年份："))

if is_leap_year(year):
    print(year, "是闰年")
else:
    print(year, "不是闰年")

66. Write a program to remove all elements from a list of integers.

num_list = [1, 2, 3, 4, 2, 2, 3, 4, 4, 4]

unique_numbers = list(set(num_list))

print("去重后的列表为：", unique_numbers)

67. Write a program to determine whether a string is a valid bracket sequence (that is, the opening and closing of the brackets match correctly).

def is_valid_parentheses(s):
    stack = []
    mapping = {
    
    ')': '(', '}': '{', ']': '['}
    for char in s:
        if char in mapping.values():
            stack.append(char)
        elif char in mapping.keys():
            if not stack or mapping[char] != stack.pop():
                return False
    return not stack

string = input("请输入一个括号序列：")

if is_valid_parentheses(string):
    print("是有效的括号序列")
else:
    print("不是有效的括号序列")

68. Write a program to find the kth largest element in a list.

def find_kth_largest(lst, k):
    sorted_list = sorted(lst, reverse=True)
    return sorted_list[k-1]

num_list = [1, 5, 2, 8, 4, 9, 3]
k = 3

kth_largest = find_kth_largest(num_list, k)

print("列表中第", k, "大的元素为：", kth_largest)

69. Write a program to determine whether a number is prime (divisible only by 1 and itself).

def is_prime(num):
    if num < 2:
        return False
    for i in range(2, int(num**0.5) + 1):
        if num % i == 0:
            return False
    return True

number = int(input("请输入一个整数："))

if is_prime(number):
    print(number, "是质数")
else:
    print(number, "不是质数")

70. Write a program that counts the length of each word in a string and outputs the longest and shortest word length.

string = input("请输入一个字符串：")

words = string.split()

word_lengths = [len(word) for word in words]

max_length = max(word_lengths)
min_length = min(word_lengths)

print("最长单词长度：", max_length)
print("最短单词长度：", min_length)

Here is the code sample for questions 61 to 70. If you have any other questions, please keep asking!