Perl

Check if Integer Exists at JSON Path

Demonstrates how to get an integer value at a JSON path, and how to check to see if it exists. Chilkat2 Perl

use strict;
use warnings;
use Chilkat2;

my $success = 0;

my $json = Chilkat2::JsonObject->new;

# First build simple JSON..
$json->UpdateInt('test.abc', 100);

$json->EmitCompact(0);
print $json->Emit(), "\n";

# This is our JSON:
# {
#   "test": {
#     "abc": 100,
#   }
# }

my $path = 'test.notHere';

# The call to IntOf will return 0, because it's not present.
# But how do we know if it really was present, and the value was truly 0?
my $val = $json->IntOf($path);
print 'val = ', $val, "\n";

# We cannot use LastMethodSuccess because LastMethodSuccess only applies
# to methods that:
# - return a string
# - return a new Chilkat object, binary bytes, or a date/time.
# - returns a boolean status where 1 = success and 0 = failed.
# - returns an integer where failure is defined by a return value less than zero.
# The IntOf method fits none of these requirements, and therefore the LastMethodSuccess
# is not a valid indicator..
my $wasFound = $json->LastMethodSuccess;
print 'wasFound = ', ($wasFound ? 1 : 0), " (not a valid indicator)\n";

# Instead, if the returned value is 0, we can double-check to see if the member was truly there..
if ($val == 0) {
    $wasFound = $json->HasMember($path);
    print 'wasFound = ', ($wasFound ? 1 : 0), "\n";
    if ($wasFound) {
        print "The value was present and is 0.\n";
    } else {
        print "no member is present at test.notHere\n";
    }
} else {
    print 'val = ', $val, "\n";
}

# Alternatively, you could check to see if the member exists beforehand..
if ($json->HasMember($path)) {
    print 'val = ', $json->IntOf($path), "\n";
} else {
    print 'no member at ', $path, "\n";
}