From list of integers, get number closest high and low to a given value-CodePudding

I would like to get the following output with two functions :

>>> myList = [25, 35, 57, 61, 79]
>>> myNumber = 38
>>> take_closest_high(myList, myNumber)
...
57
>>> take_closest_low(myList, myNumber)
35
...

The list is not necessarily ordered.

Thank you !

I have seen from another topic this solution

min(myList, key=lambda x:abs(x-myNumber))

that returns the closest number of the list

EDIT : I made it work with the following. Thanks !

min(myList, key=lambda x:abs(x-38) if x-38>0 else x)
Out[8]: 57
min(myList, key=lambda x:abs(x-38) if x-38<0 else x)
Out[9]: 35

CodePudding user response：

To get the closest high, filter myList such that all of its elements are greater than myNumber, and return the smallest value.

def take_closest_high(myList, myNumber) :
    filteredHigh = list(filter(lambda x : x>myNumber, myList))
    if filteredHigh==[] :
        return None
    return min(filteredHigh)

To get the closest low, filter myList such that all of its elements are lower than myNumber, and return the greatest value.

def take_closest_low(myList, myNumber) :
    filteredLow = list(filter(lambda x : x<myNumber, myList))
    if filteredLow==[] :
        return None
    return max(filteredLow)

CodePudding user response：

Using min & max with default on generators. Default provides value for empty lists.

Code

def take_closest_high(myList, myNumber):
    # Min over numbers in list >= myNumber
    return min((x for x in myList if x >= myNumber), default = None)

def take_closest_low(myList, myNumber):
    # Max over numbers in list <= myNumber
    return max((x for x in myList if x <= myNumber), default = None)