在PHP中传递变量

时间：2014-09-18 21:57:10

标签： php json

我刚开始学习PHP（我有一些温和的Java exp）

但我无法弄清楚如何简单地将变量作为参数传递。

请参阅下面的修补地下api。我为我需要传递的URL创建变量，但是当我把它放在第二行时，它似乎没有读取变量。 url是有问题的变量。当我直接将url作为参数放置时，它可以正常工作。但是，下面的代码会出错。

  <?php
     $url = "http://api.wunderground.com/api/KEY/geolookup/conditions/q/IA/19115";
      $json_string = file_get_contents($url);
      $parsed_json = json_decode($json_string);
      $location = $parsed_json->{'location'}->{'city'};
      $temp_f = $parsed_json->{'current_observation'}->{'temp_f'};
      echo "Current temperature in ${location} is: ${temp_f}\n";
    ?>

错误：

Notice: Undefined property: stdClass::$location in D:\Dev\xampp\htdocs\welcome.php on line 6

Notice: Trying to get property of non-object in D:\Dev\xampp\htdocs\welcome.php on line 6

Notice: Undefined property: stdClass::$current_observation in D:\Dev\xampp\htdocs\welcome.php on line 7

Notice: Trying to get property of non-object in D:\Dev\xampp\htdocs\welcome.php on line 7
Current temperature in is:

在浏览器中使用URL时的JSON响应：

{
  "response": {
  "version":"0.1",
  "termsofService":"http://www.wunderground.com/weather/api/d/terms.html",
  "features": {
  "geolookup": 1
  ,
  "conditions": 1
  }
    }
        ,   "location": {
        "type":"CITY",
        "country":"US",
        "country_iso3166":"US",
        "country_name":"USA",
        "state":"PA",
        "city":"Philadelphia",
        "tz_short":"EDT",
        "tz_long":"America/New_York",
        "lat":"40.09180450",
        "lon":"-75.04257202",
        "zip":"19115",
        "magic":"1",
        "wmo":"99999",
        "l":"/q/zmw:19115.1.99999",
        "requesturl":"US/PA/Philadelphia.html",
        "wuiurl":"http://www.wunderground.com/US/PA/Philadelphia.html",
        "nearby_weather_stations": {
        "airport": {
        "station": [
        { "city":"Northeast Philadelphia", "state":"PA", "country":"US", "icao":"KPNE", "lat":"40.07889938", "lon":"-75.01335144" }
        ,{ "city":"Philadelphia Wings Airport", "state":"PA", "country":"US", "icao":"KLOM", "lat":"40.13755417", "lon":"-75.26513672" }
        ,{ "city":"Mount Holly", "state":"NJ", "country":"US", "icao":"KVAY", "lat":"39.94076157", "lon":"-74.84071350" }
        ,{ "city":"Doylestown", "state":"PA", "country":"US", "icao":"KDYL", "lat":"40.33015823", "lon":"-75.12286377" }
        ]
        }
        ,
        "pws": {
        "station": [
        {
        "neighborhood":"Beth Ayres/High Road",
        "city":"Huntingdon Valley",
        "state":"PA",
        "country":"US",
        "id":"KPAHUNTI3",
        "lat":40.115807,
        "lon":-75.053764,
        "distance_km":2,
        "distance_mi":1
        },
        {
        "neighborhood":"Grant and Academy",
        "city":"Philadelphia",
        "state":"PA",
        "country":"US",
        "id":"KPAPHILA26",
        "lat":40.069057,
        "lon":-75.006996,
        "distance_km":3,
        "distance_mi":2
        },
        {
        "neighborhood":"Bryn Athyn",
        "city":"Huntingdon Valley",
        "state":"PA",
        "country":"US",
        "id":"KPAHUNTI4",
        "lat":40.133362,
        "lon":-75.060265,
        "distance_km":4,
        "distance_mi":2
        },
        {
        "neighborhood":"Rydal",
        "city":"Jenkintown",
        "state":"PA",
        "country":"US",
        "id":"KPAJENKI3",
        "lat":40.098648,
        "lon":-75.100975,
        "distance_km":5,
        "distance_mi":3
        },
        {
        "neighborhood":"Philadelphia",
        "city":"Philadelphia",
        "state":"PA",
        "country":"US",
        "id":"KPAPHILA37",
        "lat":40.126778,
        "lon":-74.996559,
        "distance_km":5,
        "distance_mi":3
        },
        {
        "neighborhood":"Chalfont",
        "city":"Philadelphia",
        "state":"PA",
        "country":"US",
        "id":"KPAPHILA45",
        "lat":40.076885,
        "lon":-74.977242,
        "distance_km":5,
        "distance_mi":3
        },
        {
        "neighborhood":"Elkin\u0027s Park - Logan\u0027s Alley",
        "city":"Jenkintown",
        "state":"PA",
        "country":"US",
        "id":"KPAJENKI4",
        "lat":40.085697,
        "lon":-75.126213,
        "distance_km":7,
        "distance_mi":4
        },
        {
        "neighborhood":"Willow Grove Weather Center",
        "city":"Willow Grove",
        "state":"PA",
        "country":"US",
        "id":"KPAWILLO7",
        "lat":40.142101,
        "lon":-75.106400,
        "distance_km":7,
        "distance_mi":4
        },
        {
        "neighborhood":"NOS_PORTS Tacony-Palmyra Bridge, NJ",
        "city":"Philadelphia",
        "state":"PA",
        "country":"US",
        "id":"MTPBN4",
        "lat":40.011940,
        "lon":-75.042999,
        "distance_km":8,
        "distance_mi":5
        },
        {
        "neighborhood":"Cinnaminson Street",
        "city":"Riverton",
        "state":"NJ",
        "country":"US",
        "id":"KNJRIVER2",
        "lat":40.010277,
        "lon":-75.010132,
        "distance_km":9,
        "distance_mi":5
        },
        {
        "neighborhood":"Fitzwatertown",
        "city":"Willow Grove",
        "state":"PA",
        "country":"US",
        "id":"KPAWILLO10",
        "lat":40.149128,
        "lon":-75.129265,
        "distance_km":9,
        "distance_mi":5
        },
        {
        "neighborhood":"Dresher Pa",
        "city":"Dresher",
        "state":"PA",
        "country":"US",
        "id":"KPADRESH3",
        "lat":40.138088,
        "lon":-75.150169,
        "distance_km":10,
        "distance_mi":6
        },
        {
        "neighborhood":"",
        "city":"Palmyra",
        "state":"NJ",
        "country":"US",
        "id":"KNJPALMY4",
        "lat":40.000000,
        "lon":-75.010002,
        "distance_km":10,
        "distance_mi":6
        },
        {
        "neighborhood":"North Hills",
        "city":"North Hills",
        "state":"PA",
        "country":"US",
        "id":"KPANORTH5",
        "lat":40.116211,
        "lon":-75.165329,
        "distance_km":10,
        "distance_mi":6
        },
        {
        "neighborhood":"",
        "city":"Cinnaminson",
        "state":"NJ",
        "country":"US",
        "id":"KNJCINNA2",
        "lat":39.997898,
        "lon":-75.008797,
        "distance_km":10,
        "distance_mi":6
        },
        {
        "neighborhood":"Croydon",
        "city":"Croydon",
        "state":"PA",
        "country":"US",
        "id":"KPACROYD1",
        "lat":40.087749,
        "lon":-74.903839,
        "distance_km":11,
        "distance_mi":7
        },
        {
        "neighborhood":"Delran-Millside Heights",
        "city":"Delran",
        "state":"NJ",
        "country":"US",
        "id":"KNJDELRA2",
        "lat":40.008129,
        "lon":-74.955276,
        "distance_km":11,
        "distance_mi":7
        },
        {
        "neighborhood":"oreland",
        "city":"Oreland",
        "state":"PA",
        "country":"US",
        "id":"KPAORELA2",
        "lat":40.119926,
        "lon":-75.177963,
        "distance_km":11,
        "distance_mi":7
        },
        {
        "neighborhood":"Weather Genius @ Old Wyndmoor",
        "city":"Wyndmoor",
        "state":"PA",
        "country":"US",
        "id":"KPAWYNDM3",
        "lat":40.078907,
        "lon":-75.192093,
        "distance_km":12,
        "distance_mi":7
        },
        {
        "neighborhood":"CWOP# AR939",
        "city":"Penndel",
        "state":"PA",
        "country":"US",
        "id":"KPAPENND1",
        "lat":40.156097,
        "lon":-74.917603,
        "distance_km":12,
        "distance_mi":7
        },
        {
        "neighborhood":"Downtown Fort Washington",
        "city":"Fort Washington",
        "state":"PA",
        "country":"US",
        "id":"KPAFORTW5",
        "lat":40.147438,
        "lon":-75.179253,
        "distance_km":13,
        "distance_mi":7
        },
        {
        "neighborhood":"Church Rd, Cinnaminson",
        "city":"Cinnaminson",
        "state":"NJ",
        "country":"US",
        "id":"KNJCINNA1",
        "lat":39.979568,
        "lon":-74.991234,
        "distance_km":13,
        "distance_mi":7
        },
        {
        "neighborhood":"West Mount Airy",
        "city":"Philadelphia",
        "state":"PA",
        "country":"US",
        "id":"KPAPHILA32",
        "lat":40.058418,
        "lon":-75.192741,
        "distance_km":13,
        "distance_mi":7
        },
        {
        "neighborhood":"Mount Airy",
        "city":"Philadelphia",
        "state":"PA",
        "country":"US",
        "id":"KPAPHILA54",
        "lat":40.054298,
        "lon":-75.191826,
        "distance_km":13,
        "distance_mi":8
        },
        {
        "neighborhood":"HorshamWeather.Com",
        "city":"Horsham",
        "state":"PA",
        "country":"US",
        "id":"KPAHORSH1",
        "lat":40.192310,
        "lon":-75.129883,
        "distance_km":13,
        "distance_mi":8
        },
        {
        "neighborhood":"Maple Glen",
        "city":"Maple Glen",
        "state":"PA",
        "country":"US",
        "id":"KPAMAPLE4",
        "lat":40.162884,
        "lon":-75.170181,
        "distance_km":13,
        "distance_mi":8
        },
        {
        "neighborhood":"Germantown",
        "city":"Philadelphia",
        "state":"PA",
        "country":"US",
        "id":"KPAPHILA39",
        "lat":40.023037,
        "lon":-75.173729,
        "distance_km":13,
        "distance_mi":8
        },
        {
        "neighborhood":"Port Richmond (JcWeather)",
        "city":"Philadelphia",
        "state":"PA",
        "country":"US",
        "id":"KPAPHILA4",
        "lat":39.980930,
        "lon":-75.112869,
        "distance_km":13,
        "distance_mi":8
        },
        {
        "neighborhood":"Germantown Ave. Chestnut Hill",
        "city":"Philadelphia",
        "state":"PA",
        "country":"US",
        "id":"KPAPHILA11",
        "lat":40.071766,
        "lon":-75.201759,
        "distance_km":13,
        "distance_mi":8
        },
        {
        "neighborhood":"Jenks Academy-Chestnut Hill",
        "city":"Philadelphia",
        "state":"PA",
        "country":"US",
        "id":"KPAPHILA53",
        "lat":40.074879,
        "lon":-75.203316,
        "distance_km":13,
        "distance_mi":8
        },
        {
        "neighborhood":"Erdenheim",
        "city":"Erdenheim",
        "state":"PA",
        "country":"US",
        "id":"KPAERDEN1",
        "lat":40.089100,
        "lon":-75.211998,
        "distance_km":14,
        "distance_mi":8
        },
        {
        "neighborhood":"",
        "city":"Richboro",
        "state":"PA",
        "country":"US",
        "id":"KPARICHB2",
        "lat":40.221783,
        "lon":-75.021301,
        "distance_km":14,
        "distance_mi":8
        },
        {
        "neighborhood":"Ivyland, PA",
        "city":"Warminster",
        "state":"PA",
        "country":"US",
        "id":"KPAWARMI4",
        "lat":40.222992,
        "lon":-75.049301,
        "distance_km":14,
        "distance_mi":8
        }
        ]
        }
        }
    }
  , "current_observation": {
        "image": {
        "url":"http://icons.wxug.com/graphics/wu2/logo_130x80.png",
        "title":"Weather Underground",
        "link":"http://www.wunderground.com"
        },
        "display_location": {
        "full":"Philadelphia, PA",
        "city":"Philadelphia",
        "state":"PA",
        "state_name":"Pennsylvania",
        "country":"US",
        "country_iso3166":"US",
        "zip":"19115",
        "magic":"1",
        "wmo":"99999",
        "latitude":"40.09180450",
        "longitude":"-75.04257202",
        "elevation":"46.00000000"
        },
        "observation_location": {
        "full":"Beth Ayres/High Road, Huntingdon Valley, Pennsylvania",
        "city":"Beth Ayres/High Road, Huntingdon Valley",
        "state":"Pennsylvania",
        "country":"US",
        "country_iso3166":"US",
        "latitude":"40.115807",
        "longitude":"-75.053764",
        "elevation":"250 ft"
        },
        "estimated": {
        },
        "station_id":"KPAHUNTI3",
        "observation_time":"Last Updated on September 18, 6:04 PM EDT",
        "observation_time_rfc822":"Thu, 18 Sep 2014 18:04:46 -0400",
        "observation_epoch":"1411077886",
        "local_time_rfc822":"Thu, 18 Sep 2014 18:04:53 -0400",
        "local_epoch":"1411077893",
        "local_tz_short":"EDT",
        "local_tz_long":"America/New_York",
        "local_tz_offset":"-0400",
        "weather":"Clear",
        "temperature_string":"71.0 F (21.7 C)",
        "temp_f":71.0,
        "temp_c":21.7,
        "relative_humidity":"66%",
        "wind_string":"Calm",
        "wind_dir":"SSW",
        "wind_degrees":207,
        "wind_mph":0.0,
        "wind_gust_mph":0,
        "wind_kph":0,
        "wind_gust_kph":0,
        "pressure_mb":"1016",
        "pressure_in":"30.01",
        "pressure_trend":"0",
        "dewpoint_string":"59 F (15 C)",
        "dewpoint_f":59,
        "dewpoint_c":15,
        "heat_index_string":"NA",
        "heat_index_f":"NA",
        "heat_index_c":"NA",
        "windchill_string":"NA",
        "windchill_f":"NA",
        "windchill_c":"NA",
        "feelslike_string":"71.0 F (21.7 C)",
        "feelslike_f":"71.0",
        "feelslike_c":"21.7",
        "visibility_mi":"10.0",
        "visibility_km":"16.1",
        "solarradiation":"--",
        "UV":"1","precip_1hr_string":"0.00 in ( 0 mm)",
        "precip_1hr_in":"0.00",
        "precip_1hr_metric":" 0",
        "precip_today_string":"0.00 in (0 mm)",
        "precip_today_in":"0.00",
        "precip_today_metric":"0",
        "icon":"clear",
        "icon_url":"http://icons.wxug.com/i/c/k/clear.gif",
        "forecast_url":"http://www.wunderground.com/US/PA/Philadelphia.html",
        "history_url":"http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=KPAHUNTI3",
        "ob_url":"http://www.wunderground.com/cgi-bin/findweather/getForecast?query=40.115807,-75.053764",
        "nowcast":""
    }
}

3 个答案:

答案 0 :(得分：0)

实际上输出没有问题。

如果我使用你的代码并在$json_string中，我将你提供的JSON字符串用于以下代码（与你的相同）：

$json_string = 'Here is the JSON string you provided';
$parsed_json = json_decode($json_string);
$location = $parsed_json->{'location'}->{'city'};
$temp_f = $parsed_json->{'current_observation'}->{'temp_f'};
echo "Current temperature in ${location} is: ${temp_f}\n";

我得到输出：

  

费城目前的气温为：71

当然我会使用更简单的表示法：

$json_string = 'Here is the JSON string you provided';
$parsed_json = json_decode($json_string);
$location = $parsed_json->location->city;
$temp_f = $parsed_json->current_observation->temp_f;
echo "Current temperature in {$location} is: {$temp_f}\n";

但它会给我完全相同的结果：

  

费城目前的气温为：71

我已经在PHP 5.3和PHP 5.5中对它进行了测试，在这两个版本中代码都没有任何问题，因此您可能无法始终获得API提供的结果。

所以你应该检查json_decode的结果是否为null：

$json_string = 'Not valid JSON string';
$parsed_json = json_decode($json_string);
if (!is_null($parsed_json)) {
    $location = $parsed_json->location->city;
    $temp_f = $parsed_json->current_observation->temp_f;
    echo "Current temperature in {$location} is: {$temp_f}\n";
}
else {
    echo "JSON cannot be encoded";
}

如果我在没有更改的情况下运行此代码，我会得到：

  

JSON无法编码

答案 1 :(得分：0)

而不是KEY，您需要放置您的API密钥，然后以下代码将起作用我保证：

$url = "http://api.wunderground.com/api/Your_Key/conditions/q/CA/San_Francisco.json";
$json_string = file_get_contents($url);
$parsed_json = json_decode($json_string, true);

if (isset($parsed_json['response']['error']) {
    die('error occured');
}

$location = $data['current_observation']['display_location']['city'];
$temp_f = $data['current_observation']['temp_f'];
echo "Current temperature in $location is: $temp_f\n";

答案 2 :(得分：0)

正确答案：

<?php
 $url = "http://api.wunderground.com/api/KEY/geolookup/conditions/q/IA/19115.json";
  $json_string = file_get_contents($url);
  $parsed_json = json_decode($json_string);
  $location = $parsed_json->location->city;
  $temp_f = $parsed_json->current_observation->temp_f;
  echo "Current temperature in {$location} is: {$temp_f}\n";
?>
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