What does z=map(lambda x, y:(x+y)**2,x,y) looks like in a list?

Asked May 06 '22 at 22:14

Active May 07 '22 at 04:32

Viewed 42 times

-1

I would like to know how two of map and lambda work together.

Given

x=[0,1,2,3,4]
y=[0,1,4,9,16]
z=map(lambda x, y:(x+y)**2,x,y)

I tried to use

[i for i in z]

print(z)

to show the contents in z

and hopefully I expect the result

something is like this

[0,4,36,144,400]

but nothing happens

What is valid syntax to show that?

edited May 07 '22 at 04:32

asked May 06 '22 at 22:14

Stats Cruncher

1

`[for i in z]` is invalid syntax, so you should get a `SyntaxError`. What do you mean nothing happens? – wjandrea May 06 '22 at 23:26
print out z or show contents of z.. – Stats Cruncher May 06 '22 at 23:27
@wjandrea What is valid symtax to show z? – Stats Cruncher May 06 '22 at 23:31
1

It looks like you want `list(z)`, although the numbers in the output don't match. Either you meant `** 2`, or the output should be `[0, 4, 12, 24, 40]`. – wjandrea May 06 '22 at 23:32
I'm still confused why you say "nothing happens" – wjandrea May 06 '22 at 23:34
@wjandrea Yes, `**` is what I mean. Also two of `map` and `lambda` are required to show z. – Stats Cruncher May 06 '22 at 23:37
`z = [(xx+yy)**2 for xx, yy in zip(x, y)]`. – 9769953 May 06 '22 at 23:50
1

You should at least see something like ``. Not "nothing". – 9769953 May 06 '22 at 23:51
@9769953 I tried `print(list(z))`. only `[]` showed. – Stats Cruncher May 06 '22 at 23:53
@9769953 But `map` and `lambda` are what I needed to print their result. – Stats Cruncher May 06 '22 at 23:56
things like `[0,4,36,144,400]` – Stats Cruncher May 06 '22 at 23:57
1

If you see an empty list, `[]`, then you've already iterated once through z before you printed it. You can't do `list(z)` twice when it's a map, only once. If you use *just* the first three lines of code in your question, then directly after that `print(list(z))`, you should get the wanted output. – 9769953 May 07 '22 at 00:02
@9769953 Wow, I finally see that z. How amazed you are! – Stats Cruncher May 07 '22 at 00:04

What does z=map(lambda x, y:(x+y)**2,x,y) looks like in a list?

0 Answers0