How do I slice an array in KRL

Question

I have a bunch of HTML fragments in an array (thank you query()) but I only want to use the first five. I'm using foreach to inject the fragments into a page.

If my array was [0,1,2,3,4,5,6,7,8] I would want just [0,1,2,3,4]. In Python I would use A[:5].

How can I select the first few elements of an array and ignore the rest?

score 2 · Accepted Answer · answered Mar 25 '11 at 06:34

2

You can use pick() for this, but it only appears to work correctly if the items in your array are objects, not numbers or strings:

    a = [{'n':"a"},{'n':"b"},{'n':"c"},{'n':"d"}];
    b = a.pick("$[2:]");

in the above example, b == [{'n' :'c'}, {'n' :'d'}]

I've filed a bug about the number and string failures.

It would also be possible to create a recursive function that returned the proper slice of the array, but it does sound a bit painful.

answered Mar 25 '11 at 06:34

TelegramSam

2,770
1
17
22

get_five = function(a) {a.pick("$[5:]")} //given the bug fix – Randall Bohn Mar 25 '11 at 15:26
foreach my_dataset[:5] setting (n) // provide slice to foreach – Randall Bohn Apr 08 '11 at 14:45
foreach my_dataset.pick("$[:5]") setting (n) //correct way to foreach the slice. – TelegramSam Apr 09 '11 at 04:35

How do I slice an array in KRL

1 Answers1