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python - Find the closest elements above and below a given number

myArr = array([4,1,88,44,3])
myNumber = 25
FindClosest(myArr, myNumber)
...
4, 44

Is there any way to find the closest 2 numbers in a list to a given number such that one of them is higher and the other lower?

I can find the closest number by:

min(myArr.tolist(), key=lambda x:abs(x-myNumber))
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Sorting is not necessary, and makes this time complexity O(n logn) when it should be just O(n).

I believe this is what you're looking for, taking advantage of numpy array indexing:

>>> # the smallest element of myArr greater than myNumber
>>> myArr[myArr > myNumber].min()  
44

>>> # the largest element of myArr less than myNumber
>>> myArr[myArr < myNumber].max()
4

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