nums = [5, 12, 7, 9, 21, 7, 14]
#统计数字7在列表中出现的次数,并打印结果。
count_nums = len(nums)
print("数字7在列表中出现的次:",count_nums)
#判断列表中是否存在数字99,如果不存在,则将99添加到列表末尾。
if 99 not in nums:
nums.append(99)
#打印添加后的新列表。
print("判断列表中是否存在数字99,如果不存在,则将99添加到列表末尾:",nums)
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