#原始列表
nums=[5,12,7,9,21,7,14]
#统计数字7出现的次数
count_seven=nums.count(7)
print("数字7出现的次数:",count_seven)
#判断99是否存在, 不存在则添加
if 99 not in nums:
nums.append(99)
print("添加99后的列表:",nums)
#删除第一次出现的数字7
print("删除第一个7后的列表:",nums)
#取出第2个到第4个元素(索引1到3)
sub_list=nums[1:4]
print("第2~4个元素组成的列表:",sub_list)
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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
数字7出现的次数: 2
添加99后的列表: [5, 12, 7, 9, 21, 7, 14, 99]
删除第一个7后的列表: [5, 12, 9, 21, 7, 14, 99]
第2~4个元素组成的列表: [12, 9, 21]
长度: 15
小写字母个数: 5
结果: hello 123 python