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pythonlistalgorithm

Print values from one list not contained in another

I want to check whether the elements in two arrays are different using Python.

I don't want to use numpy and sticking with general Python.

Here is an example below:

arr1 = [1,2,3,4,5,6,7]
arr2 = [1,2,3,4,5,6,7,8,9,10]

I expect the output to be [8,9,10]

So far I've tried to carry out a for loop

for x in range(len(arr1)):
    for y in range(len(arr2)):
        if arr1[x] != arr2[y]:
            print(arr2[y])

But, I receive this as output from print statement - 2345678910134567891012456789101235678910123467891012345789101234568910

Solution

  • With python one-liner:

    res = [x for x in array2 if x not in array1]
print(res) # Output : [8, 9, 10]

    Equivalent method for conventional iteration

    lst = []
for x in array2:
    if x not in array1:
        lst.append(x)
print(lst) # Output : [8, 9, 10]