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Hello, please, I would like to copy a certain list in python. The total list size is 150 and I wish to remove the last 50 elements from the list. Here I will represent a list 100 times smaller, ie with 15 elements and I wish to remove the last 5.
l = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
How could I do that in a gap for? or while?
Thank you very much!
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Actually to copy the last five of them to another list:
l2 = l[-5:] # l2 = [11, 12, 13, 14, 15]
To remove the last five:
del l[-5:] # l = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
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In Python version 2.7 just do it like this
l2= l[:-5]
I am using Python 3. Could you explain to me what was done on this line of yours? L2 = l[:-5]? I could replace with: L2 = l[:-taxa_c]?
yeah vc simply says how many elements you want to remove from the end of your list/vector in this case was -5 that is to remove the last 5 elements from the list, in your question if you want to remove the last 50 just put -50
Understood, friend, about what I asked there to replace the -5 by a variable is possible? Is that my algorithm is variant so the rate of how much should be removed varies depending on the size of the list.
But of course without any problem, can put variable will work perfectly, I tested on python3 here and worked tbm :-)
cool, thank you very much @ederwander. Take the opportunity to ask you also, I tried to find here in the community, but I did not find the answer. If for example I have a float value: value = 50.1345 but I would like to take only the entire part of it, in this case the 50 just, doing a cast here for int(value) work sometimes, but not always. It makes my while doesn’t always work. Know how to "truncate" in 50? No convert?
humm yes try that import math
b=50.1345
print(math.floor(b))
So, if you do a b how it works there, but here in the formula it didn’t work =/ maybe it’s because of the way it’s being solved? My formula is something like: b = (tamanho_populacao * taxa)
Ai no longer know, has little information, formula a question with as much information as possible that makes it easier to help you
Take some value that is giving problem in your while to understand ...
Let’s go continue this discussion in chat.
hello friend, join the chat and I’ll explain =) http://chat.stackexchange.com/rooms/42602/discussion-between-allan-and-ederwander
but it worked out that the problem was in tamanho_populacao =)
What if I needed to get the top 10? What would that look like you showed me?
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I found a solution, but I don’t know if it’s right:
l = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
percent_l = 0.5
TAM = len(l)
taxa_c = int(percent_l * TAM)
print("taxa_c",taxa_c)
new_list = []
for i in l[0:taxa_c]:
new_list.append(i)
print("new_list", new_list)
In that case I am calculating by a rate, how many last in percentage I would like to remove.
what huge code haha, take a look at my see if it works its version is 2.7?
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I posted an answer made in a pythonica way, you need it to be inside a loop or have no need ?
– ederwander
(10 times smaller )
– jsbueno