45 lines
1.2 KiB
Python
45 lines
1.2 KiB
Python
# 练习 1：九九乘法表（经典嵌套循环）
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# 题目： 打印标准的九九乘法表。
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for i in range(1, 10):
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for j in range(1, i + 1):
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print(f"{j}*{i}={i*j}", end='\t')
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print()
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# 练习 2：计算列表中的素数个数
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# 题目： 给定一个整数列表，找出其中的素数个数。
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def is_prime(n):
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if n < 2: return False
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for i in range(2, int(n**0.5) + 1):
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if n % i == 0:
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return False
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return True
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def count_primes(lst):
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count = 0
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for num in lst:
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if is_prime(num):
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count += 1
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return count
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# 练习 3：找出字符串中出现次数最多的字符
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# 题目： 给定字符串 "aabbbccccdd", 输出出现次数最多的字符和次数（如：'c', 4）
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def most_common_char(s):
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max_count = 0
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result = ''
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for char in set(s):
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count = s.count(char)
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if count > max_count:
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max_count = count
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result = char
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return result, max_count
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# 练习 4：列表去重但保持原顺序
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# 题目： 输入 [1, 2, 2, 3, 1, 4]，输出 [1, 2, 3, 4]
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def dedupe_keep_order(lst):
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result = []
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for item in lst:
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if item not in result:
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result.append(item)
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return result
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