我正在尝试显示来自开放式天气api的数据，并且我已经成功使用了该api并从中输出了一些数据。但是，我正在使用的API给我每小时的数据。但是我只想要API响应中所有5天的第一个数据集。
我遍历了我想要的所有字段，但是过去3个小时给了我每个字段。我只想要5天的字段。 （它应该给我5个结果，但在过去5天里每小时都给我结果）
所以我的问题是，如何通过遍历API响应仅获得5天的结果，而不是每小时获取一次呢？ 这是我的代码：
$currentjson_string = file_get_contents("https://api.openweathermap.org/data/2.5/weather?q=Shanghai&appid=&units=imperial");
$forecastjson_string = file_get_contents("https://api.openweathermap.org/data/2.5/forecast?q=Shanghai&appid=&units=imperial");
$currentParsed = json_decode($currentjson_string, true);
$forecastParsed = json_decode($forecastjson_string, true);
// City Variables
$country = $currentParsed['name'];
$city = $currentParsed['sys']['country'];
// Current Weather Variables
$currentWeatherLongitude = $currentParsed['coord']['lon'];
$currentWeatherLatitude = $currentParsed['coord']['lat'];
$currentIcon = $currentParsed['weather'][0]['icon'];
$currentWeatherF = $currentParsed['main']['temp'];
$currentWeatherconditions = $currentParsed['weather'][0]['description'];
// F to C
$currentWeatherC = ($currentWeatherF - 32) * 5 / 9;
$currentWeathermin = $currentParsed['main']['temp_min'];
$currentWeathermax = $currentParsed['main']['temp_max'];
<div class="weather-info">
<div class="weather-centered-box">
<span class="weather-description" style="font-size:40px;"><center><?php echo $country . ', ' . $city ?></center></span>
<span class="current-conditions">Current Conditions</span>
<span class="weather-conditions"><center><?php echo ucwords($currentWeatherconditions) ?></center></span>
<span class="weather-location" style="font-size:24px;"><?php echo 'Latitude ' . $currentWeatherLatitude . ', Longitude ' . $currentWeatherLongitude ?></span>
<span class="weather-icon"><center><?php echo '<img src="http://openweathermap.org/img/w/'.$currentIcon.'.png" />'; ?></center></span>
<?php
echo '<span class="weather-temp-f">'.$currentWeatherF.' <sup>°</sup>F ('.round($currentWeatherC, 2).' <sup>°</sup>C)</span>';
foreach ($forecastParsed['list'] as $key) {
// This is where im stuck. I don't want all the temperatures only 5 days worth of results from the temperature not hourly?
echo $key['main']['temp'];
?>
API的JSON响应：
{
"cod": "200",
"message": 0.0042,
"cnt": 39,
"list": [
{
"dt": 1551927600,
"main": {
"temp": 53.04,
"temp_min": 51.65,
"temp_max": 53.04,
"pressure": 1027.25,
"sea_level": 1027.25,
"grnd_level": 1026.28,
"humidity": 64,
"temp_kf": 0.77
},
"weather": [
{
"id": 800,
"main": "Clear",
"description": "clear sky",
"icon": "02d"
}
],
"clouds": {
"all": 8
},
"wind": {
"speed": 15.59,
"deg": 18.5008
},
"sys": {
"pod": "d"
},
"dt_txt": "2019-03-07 03:00:00"
},
{
"dt": 1551938400,
"main": {
"temp": 54.28,
"temp_min": 53.24,
"temp_max": 54.28,
"pressure": 1026.29,
"sea_level": 1026.29,
"grnd_level": 1025.32,
"humidity": 56,
"temp_kf": 0.58
},
"weather": [
{
"id": 801,
"main": "Clouds",
"description": "few clouds",
"icon": "02d"
}
],
"clouds": {
"all": 20
},
"wind": {
"speed": 13.56,
"deg": 20.0005
},
"sys": {
"pod": "d"
},
"dt_txt": "2019-03-07 06:00:00"
},
{
"dt": 1551949200,
"main": {
"temp": 49.8,
"temp_min": 49.11,
"temp_max": 49.8,
"pressure": 1026.22,
"sea_level": 1026.22,
"grnd_level": 1025.34,
"humidity": 54,
"temp_kf": 0.39
},
"weather": [
{
"id": 803,
"main": "Clouds",
"description": "broken clouds",
"icon": "04d"
}
],
"clouds": {
"all": 64
},
"wind": {
"speed": 11.74,
"deg": 28.0067
},
"sys": {
"pod": "d"
},
"dt_txt": "2019-03-07 09:00:00"
},
{
"dt": 1551960000,
"main": {
"temp": 41.05,
"temp_min": 40.71,
"temp_max": 41.05,
"pressure": 1027,
"sea_level": 1027,
"grnd_level": 1026.12,
"humidity": 70,
"temp_kf": 0.19
},
"weather": [
{
"id": 801,
"main": "Clouds",
"description": "few clouds",
"icon": "02n"
}
],
"clouds": {
"all": 24
},
"wind": {
"speed": 9.89,
"deg": 38.5044
},
"sys": {
"pod": "n"
},
"dt_txt": "2019-03-07 12:00:00"
},
{
"dt": 1551970800,
"main": {
"temp": 35.75,
"temp_min": 35.75,
"temp_max": 35.75,
"pressure": 1027.53,
"sea_level": 1027.53,
"grnd_level": 1026.67,
"humidity": 90,
"temp_kf": 0
},
"weather": [
{
"id": 802,
"main": "Clouds",
"description": "scattered clouds",
"icon": "03n"
}
],
"clouds": {
"all": 48
},
"wind": {
"speed": 6.4,
"deg": 26.001
},
"sys": {
"pod": "n"
},
"dt_txt": "2019-03-07 15:00:00"
},
{
"dt": 1551981600,
"main": {
"temp": 34.54,
"temp_min": 34.54,
"temp_max": 34.54,
"pressure": 1026.13,
"sea_level": 1026.13,
"grnd_level": 1025.29,
"humidity": 94,
"temp_kf": 0
},
"weather": [
{
"id": 803,
"main": "Clouds",
"description": "broken clouds",
"icon": "04n"
}
],
"clouds": {
"all": 64
},
"wind": {
"speed": 3.62,
"deg": 25.0002
},
"sys": {
"pod": "n"
},
"dt_txt": "2019-03-07 18:00:00"
},
{
"dt": 1551992400,
"main": {
"temp": 34.49,
"temp_min": 34.49,
"temp_max": 34.49,
"pressure": 1025.72,
"sea_level": 1025.72,
"grnd_level": 1024.85,
"humidity": 92,
"temp_kf": 0
},
"weather": [
{
"id": 804,
"main": "Clouds",
"description": "overcast clouds",
"icon": "04n"
}
],
"clouds": {
"all": 88
},
"wind": {
"speed": 3.38,
"deg": 31.0012
},
"sys": {
"pod": "n"
},
"dt_txt": "2019-03-07 21:00:00"
},
{
"dt": 1552003200,
"main": {
"temp": 42.85,
"temp_min": 42.85,
"temp_max": 42.85,
"pressure": 1026.72,
"sea_level": 1026.72,
"grnd_level": 1025.83,
"humidity": 86,
"temp_kf": 0
},
"weather": [
{
"id": 804,
"main": "Clouds",
"description": "overcast clouds",
"icon": "04d"
}
],
"clouds": {
"all": 88
},
"wind": {
"speed": 7.49,
"deg": 72.5035
},
"sys": {
"pod": "d"
},
"dt_txt": "2019-03-08 00:00:00"
}
答案 0 :(得分：1)
您可以尝试类似的方法。由于未经测试，可能有必要修改下面的代码，但这可以使您了解如何解决此问题：
$previous_date = '';
foreach ($forecastParsed['list'] as $key) {
$dt_txt = $key['dt_txt'];
$date = new DateTime($dt_txt);
$current_date = $date->format('Y-m-d');
if ($current_date != $previous_date) { echo $key['main']['temp']; }
$previous_date = $current_date;
}
它也可以写得更简洁（即在foreach中合并前两行以消除$dt_txt变量）。
逻辑解释：
此foreach循环获取当前$key的日期时间，剥离时间戳并将其放入$current_date中。然后将$current_date与$previous_date进行比较。如果它们不匹配，则我们知道这是新的一天，并且回显了温度。 $previous_date重置为$current_date，因此该变量中的值已准备好进行下一个循环。