[oracle@jhoa ip_sec]$ cat 2.pl 
$_='{"code":0,"data":{"country":"台湾","country_id":"TW","area":"","area _id":"","region":"台湾省","region_id":"TW_01","city":"","city_id":"","county":"","county_id":"","isp":"","isp_id":"-1","ip":"125.227.116.234"}}';
if ($_ =~ /(.*?)"city":(.*?),(.*?)/){$city = $2};
$city =~ s/"//g ;
print "\$city is $city\n";
if ( ($city) ){print "1111111\n"};
[oracle@jhoa ip_sec]$ perl 2.pl 
$city is