How do you find the closest number in a list to a given value?

Finding the Closest Number in a List to a Given Value

Given a list of integers and a target number, the task is to find the number in the list that is closest to the target. This problem can be solved using various approaches:

Using Min Distance

If the order of elements in the list is not guaranteed, the min() function with the key parameter can be used. This method finds the minimum distance between each element and the target, and returns the element with the minimum distance:

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

Using Binary Search (Bisection Method)

If the list is known to be sorted, binary search can be applied to find the closest number more efficiently in O(log n) time:

def takeClosest(myList, myNumber):
    low = 0
    high = len(myList) - 1
    while low <= high:
        mid = (low + high) // 2
        if myList[mid] == myNumber:
            return myList[mid]
        elif myList[mid] < myNumber:
            low = mid + 1
        else:
            high = mid - 1
    return min([myList[low], myList[high]], key=lambda x: abs(x - myNumber))

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