一、分析数据的所在位置

在爬取数据的过程中，第一件事往往就是分析数据的所在位置。我们可以通过在腾讯天气官网按下F12，在NetWork中的一些文件里找到我们所需的数据。就像这样：
我们可以看到
在这个URL中，里面的数组包含了我们所需要的数据，即天气，晴雨天等等。那么我们就复制这个URL，接下来的工作也会围绕这个URL展开。URL： https://wis.qq.com/weather/common?source=xw&refer=h5&weather_type=observe|rise&province=%E5%8C%97%E4%BA%AC%E5%B8%82&city=%E5%8C%97%E4%BA%AC%E5%B8%82&county=%E6%B5%B7%E6%B7%80%E5%8C%BA&callback=reqwest_1627223795947

二、获得URL上的信息

通过一个一个函数file_get_contents（）就可以获得该URL上的信息。并且通过var_dump()调试输出。

代码如下（示例）：

$URL = 'https://wis.qq.com/weather/common?source=xw&refer=h5&weather_type=observe|rise&province=%E5%8C%97%E4%BA%AC%E5%B8%82&city=%E5%8C%97%E4%BA%AC%E5%B8%82&county=%E6%B5%B7%E6%B7%80%E5%8C%BA&callback=reqwest_1627115817985';
$msg = file_get_contents($URL);
var_dump($msg);

三、分析所得的信息

调试输出文本如下（）：

string(1164) "reqwest_1627115817985({"data":{"observe":{"degree":"29","humidity":"75"
,"precipitation":"0","pressure":
"996","update_time":"202107252145",
"weather":"阴","weather_code":"02",
"weather_short":"阴","wind_direction":"4",
"wind_power":"1"},"rise":{"0":
{"sunrise":"05:06","sunset":"19:35","time":"20210725"},"1":
{"sunrise":"05:07","sunset":"19:34","time":"20210726"},"10":
{"sunrise":"05:16","sunset":"19:25","time":"20210804"},"11":
{"sunrise":"05:17","sunset":"19:24","time":"20210805"},"12":
{"sunrise":"05:17","sunset":"19:23","time":"20210806"},"13":
{"sunrise":"05:18","sunset":"19:22","time":"20210807"},"14":
{"sunrise":"05:19","sunset":"19:21","time":"20210808"},"2":
{"sunrise":"05:08","sunset":"19:33","time":"20210727"},"3":
{"sunrise":"05:09","sunset":"19:33","time":"20210728"},"4":
{"sunrise":"05:10","sunset":"19:32","time":"20210729"},"5":
{"sunrise":"05:11","sunset":"19:31","time":"20210730"},"6":
{"sunrise":"05:12","sunset":"19:30","time":"20210731"},"7":
{"sunrise":"05:13","sunset":"19:29","time":"20210801"},"8":
{"sunrise":"05:14","sunset":"19:27","time":"20210802"},"9":
{"sunrise":"05:15","sunset":"19:26","time":"20210803"}}},
"message":"OK","status":200})"

这里的数据是json格式，所以我们只需要使用正则表达式匹配出相应字符串，再转换成数组即可获得我们需要的温度、天气信息。

四、正则表达式

从第一个大括号开始，到最后一个大括号结束，都是我们要的json。那么就很简单了。

$preg = '/\((.+)\)/';
preg_match($preg,$msg,$matches);

如此一来，就可以匹配出我们需要的数据。再用json_decode()解码即可。

$arr = json_decode($matches[1],true);

在这里插入图片描述
此时我们获得的$arr数组就是最上面的那行数组，即（reqwest…)，最后我们通过关联数组的查找方式即可轻松访问到我们需要的数据。

echo ($arr['data']['observe']['degree']);       //温度
echo ($arr['data']['observe']['weather']);      //天气

五、代码

$URL = 'https://wis.qq.com/weather/common?source=xw&refer=h5&weather_type=observe|rise&province=%E5%8C%97%E4%BA%AC%E5%B8%82&city=%E5%8C%97%E4%BA%AC%E5%B8%82&county=%E6%B5%B7%E6%B7%80%E5%8C%BA&callback=reqwest_1627115817985';
$msg = file_get_contents($URL);
var_dump($msg);
$preg = '/\((.+)\)/';
preg_match($preg,$msg,$matches);
$arr = json_decode($matches[1],true);
echo ($arr['data']['observe']['degree']);       //温度
echo ($arr['data']['observe']['weather']);      //天气