JSON iterate over fields

Help
,
1

Hi,

I have a JSON file:

{
    "a": 1,
    "b":{
        "c": 2
    },  
    "d": [3,4]
}

and I parse read it in with the following code:

const std = @import("std");
const Json = std.json.Value;

const input = @embedFile("file.json");

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();
    const allocator = gpa.allocator();

    var json = try std.json.parseFromSlice(Json, allocator, input, .{});
    defer json.deinit();

    const root = json.value.object;
}

From there I could get the top level fields by e.g. root.get("a") or root.get("b").
But what if I don’t know the keys and I would simply like to iterate over all keys in the current level.
Is there an iterator? Unfortunately I could not find anything in the stdlib, but I have to admit, that I am lost in the stdlib quite often.
Thanks for your help.

2

std.json.Value.object is actually std.StringArrayHashMap(Value) so you can use all its methods.
To iterate over all keys you would write

for (root.keys()) |key| {
    std.debug.print("{s}\n", .{key});
}
2 Likes
3

Thank you.