How to check if a value exists in JSON array and continue loop

Question

So I am using a for loop to determine if a specific key exists in a array. But so far every method I tried didn't work for what I am trying to accomplish.

My code looks as follow:

for i in range(1,len(opslag)):
     info_product = 'https://examplesite.com/'+str(opslag[i])+'.json'
     info_get = session.get(info_product)
     text_info_prdt = info_get.text
     json_info_prdt =json.loads(text_info_prdt)
     if json_info_prdt['product']['metafields']['meta_title_nl'] in json_info_prdt['product']['metafields']:
        print(json_info_prdt['product']['metafields']['meta_title_nl'])
     else:
         print(json_info_prdt['product']['id'])

So the value in this case json_info_prdt['product']['metafields']['meta_title_nl'] , doesn't exist in every array I am trying to loop through. So sometimes the if else statement will work, and the value will be printed. But sometimes the value json_info_prdt['product']['metafields']['meta_title_nl'] doesn't exist at all and gives me a KeyError.

So What I want to do is to get all the ID's of the products that return a KeyError but I don't want the loop to stop but to continue till it's finished. So I also don't want the loop to restart itself because that's pointless.

My JSON looks as follow:

{
   product:{
      article_code:"",
      barcode:"",
      brand_id:null,
      created_at:"2017-07-07T12:49:23+02:00",
      data01:"",
      data02:"",
      data03:"",
      delivery_date_id:null,
      has_custom_fields:true,
      has_discounts:false,
      has_matrix:false,
      hits:0,
      hs_code:null,
      id:52847777,
      image_id:130661048,
      is_visible:true,
      price_excl:0,
      price_incl:0,
      price_old_excl:0,
      price_old_incl:0,
      product_set_id:383078,
      product_type_id:null,
      search_context:"",
      shop_id:240359,
      sku:"",
      supplier_id:null,
      updated_at:"2018-07-10T10:53:15+02:00",
      variants_count:4,
      visibility:"visible",
      weight:0,
      custom_fields:[

      ],
      variants:[

      ],
      product_relations:[

      ],
      product_categories:[

      ],
      product_discounts:[

      ],
      product_type:null,
      product_filter_values:[

      ],
      product_bundles:[

      ],
      metafields:{
         meta_title_nl:"Big House",
         meta_title_en:"cxzcxzcxz",
         meta_description_nl:"This is a big house"
      },
      supplier:null,
      product_images:[

      ],
      brand:null,
      delivery_date:null,
      image:{

      },
      nl:{

      },
      en:{

      },
      tags:null
   }
}

As you can see the value meta_title_nl exists in this one, but sometimes it doesn't exist.

MadLordDev · Accepted Answer · 2018-08-25 16:05:43Z

2

The if-else-structure for catching errors is called try-except. So you should use :

try:
    print(json_info_prdt['product']['metafields']['meta_title_nl'])
except:
    print(json_info_prdt['product']['id'])

edited Aug 25, 2018 at 16:05

MadLordDev

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answered Aug 25, 2018 at 11:55

SpghttCd

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1 Comment

SpghttCd Over a year ago

You 're welcome. Btw in the not nested case of a dict, one would usually use the get method, which provides the opportunity to define a default value if key is missing. However, for nested dicts you might want to read this stackoverflow.com/q/25833613/8300135 before.

blhsing · Accepted Answer · 2018-08-25 11:59:51Z

2

You should test if the key exists in the dict if it can sometimes be absent:

Change:

if json_info_prdt['product']['metafields']['meta_title_nl'] in json_info_prdt['product']['metafields']:

to:

if 'meta_title_nl' in json_info_prdt['product']['metafields']:

answered Aug 25, 2018 at 11:59

blhsing

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