How do you change the "Cap" value of an []map[string]interface{} in go lang?

Question

I am trying to do some testing with ginkgo and gomega, I get down to the assertion error

Expected
        <[]map[string]interface {} | len:1, cap:1>: []
To equal
        <[]map[string]interface {} | len:1, cap:4>: []

I believe that the test is failing because they do not have equal "cap" values, Is there a way to make these cap values equal? Also, would having the items be in different orders cause these test to fail?

thank you

What is ginko, what is gomega? And no, you cannot control cap of a (used) map. — Volker, Apr 27 '21 at 05:16
ginko is BDD Testing framework and gomega is matcher/assertion library which goes in hand — advay rajhansa, Apr 27 '21 at 05:19
https://tour.golang.org/moretypes/13 has an example of making an array with non-default capacity. You might want something like `make([]map[string]interface{}, 1, 4)`. — Tinkerer, Apr 27 '21 at 14:30

score 0 · Answer 1 · answered Apr 27 '21 at 05:18

0

This shows that you have a slice of maps which had some data. This data is now removed. But slice capacity won't decrease. If you need to check if slice is empty, you can go to BeEmpty gomega matcher.

If you want an empty slice with known capacity, you can do it like:

obj := make([]map[string]interface{}, 4) // 4 is size you need

answered Apr 27 '21 at 05:18

advay rajhansa

1,129
9
17

How would I add data to this after initializiation? – benwasin97 Apr 27 '21 at 05:22
`obj[0] = your map` – advay rajhansa Apr 27 '21 at 05:22
previously i had it declared like ` expected = []map[string]interface{}{ { "name": expectedCompany.Name, "orders": [] interface {} } } ` but declaring it like this doesn't seem to work with the new make 4 – benwasin97 Apr 27 '21 at 05:27
```obj[0] = map[string]interface{}{ "name": your data }``` – advay rajhansa Apr 27 '21 at 05:29
I get `expected operand, found '{'` – benwasin97 Apr 27 '21 at 05:30
now i get `invalid composite literal type interface{}` – benwasin97 Apr 27 '21 at 05:32
Also, this will cause my tests to break – benwasin97 Apr 27 '21 at 05:33
you need to go through docs and learn go first. what you're asking here is out of the context for this question – advay rajhansa Apr 27 '21 at 05:34
I dont think this works `obj[0] = map[string]interface{}{ "name": your data }` and I cant find the answer – benwasin97 Apr 27 '21 at 05:54

How do you change the "Cap" value of an []map[string]interface{} in go lang?

1 Answers1