Perl

Get the Index of a JSON Member

See more JSON Examples

This example demonstrates how to get the index of a given member by name.

{
  "name": "donut",
  "image":
    {
    "fname": "donut.jpg",
    "w": 200,
    "h": 200
    },
  "thumbnail":
    {
    "fname": "donutThumb.jpg",
    "w": 32,
    "h": 32
    }
}

Perl

use chilkat();

$success = 0;

$json = chilkat::CkJsonObject->new();

# This is the above JSON with whitespace chars removed (SPACE, TAB, CR, and LF chars).
# The presence of whitespace chars for pretty-printing makes no difference to the Load
# method. 
$jsonStr = "{\"name\": \"donut\",\"image\":{\"fname\": \"donut.jpg\",\"w\": 200,\"h\": 200},\"thumbnail\":{\"fname\": \"donutThumb.jpg\",\"w\": 32,\"h\": 32}}";

$success = $json->Load($jsonStr);
if ($success == 0) {
    print $json->lastErrorText() . "\r\n";
    exit;
}

# The top-level JSON object has three members: name, image, and thumbnail.
$nameIndex = $json->IndexOf("name");
# The index of the "name" member is 0.
print "nameIndex = " . $nameIndex . "\r\n";

$thumbIndex = $json->IndexOf("thumbnail");
# The index of the "thumbnail" member is 2.
print "thumbIndex = " . $thumbIndex . "\r\n";

# The "fname" member is NOT a direct member of the top-level JSON object.
# It is a member of a nested object.  If we try to get the index of this
# member using the top-level JSON object, it is not found (and returns -1).
$fnameIndex = $json->IndexOf("fname");
# The fnameIndex is -1 (not found).  This is correct.
print "fnameIndex = " . $fnameIndex . "\r\n";

# Get the "image" object.
$imageObj = chilkat::CkJsonObject->new();
$json->ObjectOf2("image",$imageObj);

# Now we can get the index of the "fname" object, because it is a direct
# member of the "image" object:
$fnameIndex = $imageObj->IndexOf("fname");
print "fnameIndex = " . $fnameIndex . "\r\n";