Golang structure field's name and unmarshalling into this structure

Question

I wrote an example program to illustrate my question, and it can be viewed here: https://play.golang.org/p/6776lYcbBR

So my question is:

when a structure (GameOne) field's name starts with a capital letter, json.Unmarshal works as expected; when it starts with a lower-case letter (GameTwo), the field value is set to its default.

Why is this so? Has it something to do with scope/visibility rules?

Thank you in advance.

Possible duplicate of [My structures are not marshalling into json](http://stackoverflow.com/questions/15452004/my-structures-are-not-marshalling-into-json) — RdB, Feb 28 '17 at 14:54

score 1 · Accepted Answer · answered Feb 22 '17 at 08:27

1

json.Unmarshal sets only the export fields in a struct and for exporting a field the first letter must be capital.
For more information I highly suggest you to take a look to the documentation

answered Feb 22 '17 at 08:27

Tinwor

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score 1 · Answer 2 · answered Feb 22 '17 at 09:01

From the documentation (emphasis added):

Unmarshal will only set exported fields of the struct.

Fields which begin with a lowercase letter are, of course, not exported. So there's no way for the JSON marshaler (or indeed anything at all outside of your package) to affect them.

Golang structure field's name and unmarshalling into this structure

2 Answers2