python map function

Question

why output is not coming in map function without using list function

Answer 1

HonFu Lothar Change your print(...) on
print(map_)
print(*map_)
Now you can see clearly what's going on⁉️☺️
'milk' - I love it‼️☺️😃😁

Answer 2

By using list, you directly 'milk' the map you created, and create a new list from it.

After that, what you do with the old list, won't have an effect.

Answer 3

I have modified the code a bit, and it shows an unexpected behavior:

list_ = [1, 2, 3]
map_ = list(map(lambda x: x*2, list_)) # added list(....)
list_.append(4)
print(map_) # removed unpack operator.

Any idea HonFu?

Answer 4

Please look at this code:

list_ = [1, 2, 3]
map_ = map(lambda x: x*2, list_)
list_.append(4)
print(*map_)

One could assume that the output will be [2, 4, 6], because the map was created before I appended 4 to the list.

However, the output is 2 4 6 8.

So why's that?

Map does not create this *now*, it is only a preliminary construction plan for how each value is to be created as soon as the construction is started.

When you unpack the map (*), loop over it or make a list with it, only then the values will be created.

Answer 5

John, you're right, it's unpacked of course. 😅 Let me quickly change it.

Answer 6

I agree with @HonFu although the output is 2 4 6 8 on the same line but your explanation was right.

Answer 7

Umar Bello you can use the search at the top so you can get the relevant thread please.

Answer 8

How can i creat app in html.