first filter() argument as list comprehension?

Question

Hello alltogether

Can someone please shed some light on my thoughts please.

Can the Lambda func in the following codesnippet substituted with a list comprehension in some way?
As I understand it, the filter() func needs a func as first argument and a list comprehension would be a list object and not a func object.

I am wondering now if there is some elegant way to substitude the Lambda func with a list compr. anyway.

nums = [11, 22, 33, 44, 55]
res = list(filter(lambda x: x%2==0, nums))
print(res)

Answer 1

res = [ x for x in nums if x%2==0 ]

Answer 2

The filter() function itself is said to be "unpythonic" because a list comprehension does exactly the same in a more obvious way. So you could argue that using the filter function isn't elegant, much less using a list comprehension as an argument for the filter function. Why would you want to do that? 🤔

Answer 3

Allow me to clarify some issues with filter and list comprehension

1. Explicit function

The first argument does not have to be lambda function <-- CORRECT

It can be an explicit function.

https://code.sololearn.com/c4zQI01yPm9W/?ref=app
https://code.sololearn.com/c06bVu0UOOS2/?ref=app
https://code.sololearn.com/cETCb20aM5P1/?ref=app

2. List comprehension can accept tuple. But if you make output tuple it'll be a generator

https://code.sololearn.com/cIXh30zKfHrL/?ref=app

3. When the logic is simple condition, list comprehension is same as filter.

https://code.sololearn.com/cg7Ncf22uO5V/?ref=app

4. But actually list comprehension is more flexible

https://code.sololearn.com/c8lDV6FtY2ZD/?ref=app

Answer 4

nice & short
Thx for your answer Gordon

Do you can think of any way of putting a list compr. as the first argument of the func filter() and just substitute the Lambda func?

Answer 5

Hi Anna

Makes sense what you say. Thx for your input.

Me toying around with list comprehensions and collecting different samples. I still need some time to get comfortable with them.