One line for and if python

Question

I try to understand the working of the python one-line method... So I decided to code this :

pizza_result=[[1, 1], [2, 3], [3, 0]]
b=0
pizza_result=[i for i in  pizza_result if i[1]>=b]

But Now I would like change the value of b...

As:

izza_result=[i for i in  pizza_result if i[1]>=b: b=i[1] ]

But this doesn't work...

Where I have to but the =i[1]?

In a nutshell :

What I expect

I would like the element(s) who have the biggest i[1]

In This code what's aim the output ?

Here, I just want [[2,3]] because i[1] (3) > the other

BUT

But if I had : [[1,1],[2,1],[3,0]] I expect have : [[1,1],[2,1]]. Because the second number is >

But if I had : [[1,1],[2,1],[3,0]] I expect have : [[1,1],[2,1]] — BiMathAx STUDIO, Nov 14 '21 at 21:31
You need to execute the third line again after changing `b`. The last line (the one that doesn't work) is useless. You don't have to write `=i[1]` anywhere. — mkrieger1, Nov 14 '21 at 21:35
Have you read the documentation on [List Comprehensions](https://docs.python.org/3/tutorial/datastructures.html#list-comprehensions)? — martineau, Nov 14 '21 at 21:36
Fundamentally this is the same question as https://stackoverflow.com/questions/10823227/how-to-get-all-the-maximums-max-function — mkrieger1, Nov 14 '21 at 21:36

j1-lee · Accepted Answer · 2021-11-14T21:39:42.107

1

You can use max to first get max value, and then use list comprehension to filter:

pizza_result=[[1, 1], [2, 3], [3, 0], [4, 3]]

max_val = max(p[1] for p in pizza_result)
output = [x for x in pizza_result if x[1] == max_val]
print(output) # [[2, 3], [4, 3]]

edited Nov 14 '21 at 21:39

answered Nov 14 '21 at 21:35

j1-lee

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@mkrieger1 I agree! Also that makes even more sense if the list is long. – j1-lee Nov 14 '21 at 21:42

mozway · Answer 2 · 2021-11-14T23:05:06.387

0

"I would like the element(s) who have the biggest i[1]"

Use:

m = max(pizza_result, key=lambda x: x[1])[1]
[l for l in pizza_result if l[1] == m]

Output: [[2, 3], [4, 3]]

edited Nov 14 '21 at 23:05

answered Nov 14 '21 at 21:33

mozway

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Ok, now it works, though I think it's pretty much the same as the other answer, just not as good. NB. I don't see the point of explaining a downvote when you can easily explain it yourself by testing. – Kelly Bundy Nov 14 '21 at 23:31
Add I said, this was a typo during copying the answer ;) – mozway Nov 14 '21 at 23:38

One line for and if python

2 Answers2