如何在for循环中应用lambda函数

Question

I am learning how to use lambda functions in for loop and faced with this

l3=['one','two','three']
for i in l3:
    lambda i: i.upper()
    print(i)

I expect that each member of my list will be in uppercase but output is the same in lower case. What i am doing wrong ?

Answer 1

as others comment, you are printing the variable i and not calling at all the lambda

try instead:

x = lambda i: i.upper()
print(x(i)) 

Answer 2

You're defining a lambda but you're never calling it. What you probably meant is

l3 = ['one','two','three']
for i in l3:
    i = (lambda x: x.upper())(i)
    print(i)

or

l3 = ['one','two','three']
for i in l3:
    f = lambda x: x.upper()
    print(f(i))

Which are not good examples on how to use a lambda anyway.

Also, notice that I'm calling the parameter x instead of i , since that i inside the lambda wouldn't be the same i you're using to iterate the list.