msg = "hello 123 WORLD"
#统计长度和小写字母个数
length = len (msg)
lower_count = sum(1 for ch in msg if ch.islower())
print("长度:", length )
print("小写字母个数:", lower_count )
#替换并转小写
new_msg = msg. replace ("WORLD", "Python")
result = new_msg. lower ()
print("结果:", result )
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