How to get value from array

[ra1nst0rm3d]

• I want to get a value of 'id' from array items

I'm give this JSON code:

{
    "response": {
        "count": 246,
        "items": [
            {
                "id": 456239356,
                "album_id": -15,
                "owner_id": 223134400,
                "sizes": [
                    {
                        "type": "m",
                        "url": "https://sun9-25.u...4c5/FPhcIYb3UH0.jpg",
                        "width": 97,
                        "height": 130
                    },
                    {
                        "type": "o",
                        "url": "https://sun9-41.u...4c7/JDqz1u_L8p4.jpg",
                        "width": 130,
                        "height": 173
                    },
                    {
                        "type": "p",
                        "url": "https://sun9-61.u...4c8/DB5DZsOldK4.jpg",
                        "width": 200,
                        "height": 267
                    },
                    {
                        "type": "q",
                        "url": "https://sun9-4.us...4c9/ckrBy4eD8-c.jpg",
                        "width": 320,
                        "height": 427
                    },
                    {
                        "type": "r",
                        "url": "https://sun9-10.u...4ca/YMxebK1MdXE.jpg",
                        "width": 450,
                        "height": 600
                    },
                    {
                        "type": "s",
                        "url": "https://sun9-14.u...4c4/3SBIzASVRfg.jpg",
                        "width": 56,
                        "height": 75
                    },
                    {
                        "type": "x",
                        "url": "https://sun9-43.u...4c6/M2kNQnDOHEU.jpg",
                        "width": 450,
                        "height": 600
                    }
                ],
                "text": "",
                "date": 1531926387
            },
            {
                "id": 456239361,
                "album_id": -15,
                "owner_id": 223134400,
                "sizes": [
                    {
                        "type": "m",
                        "url": "https://sun9-47.u...1b6/diTkAYuSeEY.jpg",
                        "width": 97,
                        "height": 130
                    },
                    {
                        "type": "o",
                        "url": "https://sun9-5.us...1bb/UJd8Jlha1Ow.jpg",
                        "width": 130,
                        "height": 173
                    },
                    {
                        "type": "p",
                        "url": "https://sun9-49.u...1bc/FF8SEu_oBt0.jpg",
                        "width": 200,
                        "height": 267
                    },
                    {
                        "type": "q",
                        "url": "https://sun9-47.u...1bd/hXZmMKhYgFw.jpg",
                        "width": 320,
                        "height": 427
                    },
                    {
                        "type": "r",
                        "url": "https://sun9-37.u...1be/dcyHZoEEfBQ.jpg",
                        "width": 510,
                        "height": 680
                    },
                    {
                        "type": "s",
                        "url": "https://sun9-28.u...1b5/hW5bO1WXZ04.jpg",
                        "width": 56,
                        "height": 75
                    },
                    {
                        "type": "w",
                        "url": "https://sun9-31.u...1ba/m3ZFNMnSdUg.jpg",
                        "width": 1620,
                        "height": 2160
                    },
                    {
                        "type": "x",
                        "url": "https://sun9-54.u...1b7/Tzx4N7wD3YE.jpg",
                        "width": 453,
                        "height": 604
                    },
                    {
                        "type": "y",
                        "url": "https://sun9-11.u...1b8/dhmIRt3eZ8c.jpg",
                        "width": 605,
                        "height": 807
                    },
                    {
                        "type": "z",
                        "url": "https://sun9-37.u...1b9/3iavgJV9YWQ.jpg",
                        "width": 810,
                        "height": 1080
                    }
                ],
                "text": "",
                "date": 1531935090
            }
        ]
    }
}

• Arch Linux, CLang 8

• Version of library 2.1.1

[vega0]

same interesting

[vega0]

Try to
json j = json::parse("your-json-here");
int id = j["response"]["items"][0]["id"];

[nlohmann]

This should work:

json j = json::parse("your_file.json");

for (const auto& item : j["response"])
{
    int id = item["id"];
}

[ra1nst0rm3d]

I want give EVERY id value in massive

[ra1nst0rm3d]

@nlohmann, your code doesn't work

[nlohmann]

My bad:

• You need to first create an std::ifstream with your file and pass it to std::parse.
• The for loop should be for (const auto& item : j["response"]["items"]).

[ra1nst0rm3d]

@nlohmann, caught a logic_error exception

[nlohmann]

Do you have a stack trace? I need more information.

[ra1nst0rm3d]

(gdb) n [New Thread 0x7ffff6e9d700 (LWP 10480)] [Thread 0x7ffff6e9d700 (LWP 10480) exited] 46 for (const auto& item : second["response"]["items"]) (gdb) n 46 for (const auto& item : second["response"]["items"]) (gdb) n 54 }; (gdb) n 54 }; (gdb) n 54 }; (gdb) n 0x00007ffff7a31ee3 in __libc_start_main () from /usr/lib/libc.so.6 (gdb) n Single stepping until exit from function __libc_start_main, which has no line number information. [Inferior 1 (process 10474) exited normally] (gdb)

[ra1nst0rm3d]

@nlohmann, i don't know how to format code on GitHub

[nlohmann]

In order to asses your issue, we need the following information:

• What is the issue you have?

• Please describe the steps to reproduce the issue. Can you provide a small but working code example?

• What is the expected behavior?

• And what is the actual behavior instead?

• Which compiler and operating system are you using? Is it a supported compiler?

• Did you use a released version of the library or the version from the develop branch?

• If you experience a compilation error: can you compile and run the unit tests?