python中upper 怎么用_python .upper() 用法问题

题目:'''names=['Tom','Billy','Jefferson','Andrew','Wesley','Steven','Joe','Alice','Jill','Ana','Wendy','Iennifer','Sherry','Eva']找出上述名字中长度大于4的名字,组成列表打印...

题目:

'''

names=['Tom','Billy','Jefferson','Andrew','Wesley','Steven', 'Joe','Alice','Jill','Ana','Wendy','Iennifer','Sherry','Eva']

找出上述名字中长度大于4的名字,组成列表打印出来.

过滤掉长度大于5的字符串列表,并将剩下的转换成大写字母.

'''

#用for循环做出来的答案输出结果不正确

names=['Tom','Billy','Jefferson','Andrew','Wesley','Steven',

'Joe','Alice','Jill','Ana','Wendy','Jennifer','Sherry','Eva']

a=[]

b=[]

for i in names:

if len(i)>4:

a.append(i)

else:

i.upper()

b.append(i)#有问题 为什么没有大写

print(a)

print(b)

''

for 循环做出来的结果 b列表没有大写

['Billy', 'Jefferson', 'Andrew', 'Wesley', 'Steven', 'Alice', 'Wendy', 'Jennifer', 'Sherry']

['Tom', 'Joe', 'Jill', 'Ana', 'Eva']

...

列表推导式做出来的结果是正确的

...

names=['Tom','Billy','Jefferson','Andrew','Wesley','Steven',

'Joe','Alice','Jill','Ana','Wendy','Jennifer','Sherry','Eva']

a=[i for i in names if len(i)>4]#生成一个列表

print(a)

b=[i.upper() for i in names if len(i)<=4]

print(b)

'''

正确的输出结果

['Billy', 'Jefferson', 'Andrew', 'Wesley', 'Steven', 'Alice', 'Wendy', 'Jennifer', 'Sherry']

['TOM', 'JOE', 'JILL', 'ANA', 'EVA']

'''

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