Reputation: 431

How to choose the numbers which are lowest 10% in the list?

I would like to get the lowest 10% numbers in the list.

List = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]

From the above list, I expect to get the result. result = [1,2] which is the lowest 10% on the list.

Upvotes: 1

Answers (7)

shashwatjo

Reputation: 21

mylist=[int(x) for x in range(1,21)]
mylist.sort()
newlist=[]
for i in range(len(mylist)//10): #just index through the 10% elements with this
    newlist.append(mylist[i])
print(newlist)

Upvotes: 1

BlueSheepToken

Reputation: 6129

If every elements are unique, you can simply sort and slice the data

l = list(range(1, 21))

number_value_to_get = len(l)//10
print(sorted(l)[:number_value_to_get]

However, in most of the case, this is wrong, you can use the numpy version

import numpy as np

l = np.array(range(1, 21))
threshold = np.percentile(l, 10) # calculate the 10th percentile
print(l[l < threshold]) # Filter the list.

Be aware to need to define if it this is 10% inclusive or not

import numpy as np

l = np.array([1]*20)
threshold = np.percentile(l, 10)
print(l[l < np.percentile(l, 10)]) # Gives you empty list
print(l[l <= np.percentile(l, 10)]) # Gives you full list

Upvotes: 5

Zaraki Kenpachi

Reputation: 5740

Here you go =^..^=

import numpy as np

List = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]

percent = 10
values = list(sorted(np.asarray(List, dtype=np.int))[:int(len(List)/(100/percent))])

Output:

[1, 2]

Upvotes: 2

Christian Sloper

Reputation: 7510

If you want to use numpy there is a built in percentile function:

import numpy

l = numpy.array([1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20])

print(l[l < numpy.percentile(l,10)])

Upvotes: 3

user11509642

Reputation:

 # list of values
lstValues = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]

# get maximum value out of list values
max = max(lstValues)

# calculate 10 percent out of max value
max /= 10

# print all the elements which are under the 10% mark
print([i for i in lstValues if i <= max])

Upvotes: 1