PHP: parsing a specific json value

Question

I'm trying to retrieve the first two ("period": 0 and "period": 1) icon_url values from the json file showed at the bottom.

However, I'm stuck at:

for($j=0; $j<2; $j++) {
$icon[$j] = $parsed_json_forecast->{'forecast'}->{'txt_forecast'}->{'forecastday'}->

How to parse the first two icon_url values?

Of course it can't be:

[...]->{'period'}->{$j}->{'icon_url'};

Here's the json content:

{
    "response": {
        "version": "0.1",
        "termsofService": "http://www.wunderground.com/weather/api/d/terms.html",
        "features": {
            "forecast": 1
        }
    },
    "forecast": {
        "txt_forecast": {
            "date": "2:00 AM CEST",
            "forecastday": [{
                "period": 0,
                "icon": "rain",
                "icon_url": "http://icons-ak.wxug.com/i/c/k/rain.gif",
                "title": "Martedì",
                "fcttext": "Pioggia. Massima: 77F. Velocità del vento: 15-25 mph. Direzione del vento: Ovest. Possibilità di precip. 90%.",
                "fcttext_metric": "Pioggia. Massima: 25C. Velocità del vento: 30-40 km/h. Direzione del vento: Ovest. Possibilità di precip. 90%.",
                "pop": "90"
            },
            {
                "period": 1,
                "icon": "partlycloudy",
                "icon_url": "http://icons-ak.wxug.com/i/c/k/partlycloudy.gif",
                "title": "Martedì notte",
                "fcttext": "Pioggia. Minima: 63F. Velocità del vento: 5-15 mph. Direzione del vento: Ovest-NE.",
                "fcttext_metric": "Pioggia. Minima: 17C. Velocità del vento: 5-20 km/h. Direzione del vento: Ovest-NE.",
                "pop": "0"
            },
            {
                "period": 2,
                "icon": "clear",
                "icon_url": "http://icons-ak.wxug.com/i/c/k/clear.gif",
                "title": "Mercoledì",
                "fcttext": "Sereno. Massima: 77F. Velocità del vento: 5-10 mph. Direzione del vento: Sud.",
                "fcttext_metric": "Sereno. Massima: 25C. Velocità del vento: 10-15 km/h. Direzione del vento: Sud.",
                "pop": "0"
            },
            {
                "period": 3,
                "icon": "clear",
                "icon_url": "http://icons-ak.wxug.com/i/c/k/clear.gif",
                "title": "Mercoledì notte",
                "fcttext": "Sereno. Minima: 64F. Vento leggero.",
                "fcttext_metric": "Sereno. Minima: 18C. Vento leggero.",
                "pop": "20"
            },      
[....]

Thanks in advance.

$parsed_json->forecast->txt_forecast->forecastday[$j]->icon_url. You are indexing into an array, use array syntax. What is confusing about it? — Jon
– Jon, Commented Sep 17, 2013 at 10:45
That "period" value somewhat confused me (I'm still unexperienced with arrays). Of course you're right. — flapane
– flapane, Commented Sep 17, 2013 at 10:59
Thanks to anybody to answered. Sometimes it's difficult to choose just an answer as "the right one", I hope you'll understand it. — flapane
– flapane, Commented Sep 17, 2013 at 11:01

Daniel · Accepted Answer · 2013-09-17 10:53:05Z

2

When you have parsed the JSON data (e.g with json_decode) you may access each value using the regular php array syntax:

$json["forecast"]["txt_forecast"]["forecastday"][0]["period"].

Edit: It's the same for array access (SPL):

$json->forecast->txt_forecast->forecastday[0]->icon_url

edited Sep 17, 2013 at 10:53

answered Sep 17, 2013 at 10:45

Daniel

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6 Comments

Amal Over a year ago

That doesn't answer the question.

Daniel Over a year ago

@AmalMurali How does it not? Parsing json without decoding would be very resource heavy if you are thinking of preg_match or like.

Amal Over a year ago

No. The OP is using objects, but you're using associative arrays in your answer instead.

Felix Kling Over a year ago

Only if you pass true as second argument to json_decode, objects are parsed into associative arrays.

Felix Kling Over a year ago

Yes, but you can only use array syntax to access JSON data encoded as objects if you pass true as second argument and you don't mention that. If the OP just uses json_decode, they won't be able to use your solution.

|

Amal · Accepted Answer · 2013-09-17 10:59:37Z

1

You have the JSON string. Now, to extract the required values, you'll have to do:

decode the the JSON using json_decode()
loop through the required items
store them in your array

Code:

$parsed_json = json_decode($str);

for($j=0; $j<2; $j++) {
    $icon[$j] = $parsed_json->forecast->txt_forecast->forecastday[$j]->icon_url;
}

Output:

Array
(
    [0] => http://icons-ak.wxug.com/i/c/k/rain.gif
    [1] => http://icons-ak.wxug.com/i/c/k/partlycloudy.gif
)

Demo!

edited Sep 17, 2013 at 10:59

answered Sep 17, 2013 at 10:51

Amal

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Comments

Muthu Kumaran · Accepted Answer · 2013-09-17 10:55:49Z

1

First, you need to parse your json data using json_decode and you can able to extract the data,

Here's the sample code,

$data = json_decode($json);
for($j=0; $j<2; $j++) {
    echo $data->forecast->txt_forecast->forecastday[$j]->icon_url;
}

Code Demo: http://codepad.org/O9WsTs34

answered Sep 17, 2013 at 10:55

Muthu Kumaran

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