wpietri on Bruce Eckel announces he's going to write Atomic Python

Comment on Bruce Eckel announces he's going to write Atomic Python parent

Is there some language where [4,6] is the output? That strikes me as serving some use case that I've never come across. Whereas having two lists and wanting to end up with one list with all the elements is a very common need.

gknoy 11y

I believe it would be in Matlab, as [1, 2] + [3, 4] would be considered matrix addition, in which one adds elements in corresponding places. Numpy (as mentioned in the GP) probably does similar.

wpietri 11y

Ah, ok, thanks. Right, matrix math is is the use case I was looking for.

vessenes 11y

Yes, python.

   In [1]: import numpy as np

   In [2]: a = np.array([1,2])

   In [3]: b = np.array([3,4])

   In [4]: a+b

   Out[4]: array([4, 6])

bwohlergo 11y

we are talking about Lists, not arrays from an unrelated library which has to be installed first. what you've done there is simply dishonest

In [1]: a = [1,2]

In [2]: b = [4,5]

In [3]: print(a+b)

Out [1, 2, 4, 5]

Animats 11y

Is there some language where [4,6] is the output?

Yes. Python:

    >>> x = numpy.array([1,2])
    >>> y = numpy.array([3,4])
    >>> x + y
    array([4, 6])

For extra fun:

    >>> x + [3,4]
    array([4, 6])
    >>> [1,2] + y
    array([4, 6])

but, of course:

    >>> [1,2] + [3,4]
    [1, 2, 3, 4]

topogios 11y

In R:

a <- array(c(1,2))

b <- array(c(3,4))

a + b

[1] 4 6

class(a + b)

[1] "array"

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