How can I create list from elements of another list

Question

Please help me I got stuck in something that seems quite simple. I just want to create list from elements of another list. I can do it this way but cant figure out faster way because my list has around 500 elements and I dont want to write list name 500 times. Example :

testing = [ 'john', 'mark', 'joseph', 'cody', 'bill' , 'dick']
new= [testing [0], testing[3], testing[4]]

gives me what I want, but how can I make it faster. I tried

new = [testing ([0], [3], [4])]

and get 'list' object is not callable

Kraigolas · Accepted Answer · 2021-03-04 20:39:16Z

5

For the specific case of not re-writing the list name

indices = [0, 3, 4]
new = [testing[i] for i in indices]

will work. When you write

[testing ([0], [3], [4])]

You are writing testing(...). When python sees these parentheses, it thinks you are trying to call a function, which is why it says list object not callable.

There is also slicing notation like

testing[a:b:step]

to take the elements starting at a until (and not including) b in step sizes of step, but in your case you might have to take the more general approach given above where you just supply the indices yourself.

answered Mar 4, 2021 at 20:39

Kraigolas

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2 Comments

Krilnik Max Over a year ago

Thank you very much.. I am aware of slicing but needed it like this

RufusVS Over a year ago

Of course, if you don't really want/need to factor out the list of indices, just use: new = [testing[i] for i in [0, 3, 4]]

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