Find nearest value for 3 lists

Question

Here is my code to get the nearest value to a given number ( Mynumber) from a list (Mylist)

    Mylist= [ 1, 2, 3]
    Mynumber=3

    takeClosest = lambda num,collection:min(collection,key=lambda x:abs(x-
    num))
    closest= [takeClosest(Mynumber,Mylist)]

    print closest

Now I have 3 lists [ 1, 2, 3] ,[ 4, 7, 8], [ 13, 9, 10] I want to compare first item , second item and 3rd item of them with this list,[2,6,9] ,If I compare 1st item in each list, out if [1,4,13], 1 is the closest to 2 ,If I compare 2nd item in each list, out of [2,7,9], 7 is the closest to 6,If I compare 3rd item in each list, out of [3,8,10], 10 is the closest to 9 Does any one know how to do it? Any suggestion would be greatly appreciated

    """
    Mylist1= [ 1, 2, 3]
    Mylist2= [ 4, 7, 8]
    Mylist3= [ 13, 9, 10]

    Mynumber=[2,6,9]
    """

So you want to compare the first item in `Mynumber` to `Mylist1`, second item in `Mynumber` to `Mylist2` etc? — MCBama, Dec 11 '17 at 18:22
Hi MCBama, no, I want to compare first item in Mynumber to three first numbers in Mylists, second item in Mynumber to three second numbers in Mylists, and third item in Mynumber to three third numbers in Mylists. My output should be ( 1,7,8) — user9059368, Dec 11 '17 at 18:29

user2390182 · Accepted Answer · 2017-12-11T18:38:13.670

1

You could just do this using map and the zip(*...) transpositioning idiom:

>>> lists = [[1, 2, 3], [ 4, 7, 8], [13, 9, 10]]
>>> lst = [2,6,9]
>>> list(map(takeClosest, lst, zip(*lists)))
# OR:  list(map(takeClosest, Mynumber, zip(Mylist1, Mylist2, Mylist3)))
[1, 7, 8]  # 9 is as close to 8 as it is to 10

This will apply your takeClosest function to (2, [1, 4, 13]), (6, [2, 7, 9]), etc.

edited Dec 11 '17 at 18:38

answered Dec 11 '17 at 18:27

user2390182

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thank you so much for your valuable responses.. I appreciate it.. all the answers given here are correct.. but unfortunately I can not put a tick for all of them, when I put a tick for 2, one will disappear. Thank you so much every one – user9059368 Dec 13 '17 at 00:38

score 0 · Answer 2 · answered Dec 11 '17 at 18:38

Here's a kind of ugly way to do it.

Mylist1= [ 1, 2, 3]
Mylist2= [ 4, 7, 8]
Mylist3= [ 13, 9, 10]
Mynumber=[2,6,9]
closest_values = []
for num in range(len(Mynumber)):
    differences = {Mylist1[num]: abs(Mylist1[num]-Mynumber[num]), 
                   Mylist2[num]: abs(Mylist2[num]-Mynumber[num]),
                   Mylist3[num] : abs(Mylist3[num]-Mynumber[num])}
    closest_values.append(min(differences, key=differences.get))
print(closest_values)
#[1, 7, 8]

score 0 · Answer 3 · answered Dec 11 '17 at 19:44

You can try something like this:

data=[ 1, 2, 3] ,[ 4, 7, 8], [ 13, 9, 10]
true1=[2,6,9]
for i in zip(*data,true1):
    print(min([(abs(k - i[-1:][0]), k, i[-1:][0]) for k in i[:-1]])[1:])

Note that in last item [3,8,10] 8 is close to 9 :

output:

(1, 2)
(7, 6)
(8, 9)

Find nearest value for 3 lists

3 Answers3