Merge multiple JSON files (more than two)

If you just want to merge all json files sequentially,

1. go to the folder where all json files are, select all and rename the first one as "yourchoice", by doing this all will be in sequential order i.e. yourchoice1,yourchoice2 ...

2. next go to cmd and type : copy *.json "outputfilename".json

3. All of your json files are merged sequentially into the "outputfilename".json file

Here’s a simple way to merge multiple JSON files into a single list in Python. This approach loads all JSON files in the current directory, combines them into a list, and writes the merged data to a new file.

import json, glob
json_files = glob.glob("*.json")  
merged_data = [json.load(open(f)) for f in json_files]  

with open("merged.json", "w") as output:  
  json.dump(merged_data, output, indent=4)  

This is a simple solution that can work but there's a lot of issues specially when you have more than 2 files or the files contain complex data. I found this simple tool very effective , it merges literally any type of JSON files in a few clicks and lets you download the merged.json file , its very simple.

Tool : https://www.merge-json-files.com/

A way you could do it and which would result in cleaner code in to define a function that takes two JSON objects and return the combination of those two.

def merge (json_obj_1, json_obj_2):
    items = json_obj_1['items'] + json_obj_2['items']
    return { 'items': items }

Then, after you have output_list:

result = reduce(merge, output_list)

Result will be the object you are looking for.

If you're not familiar with the reduce function, check out this web page:

http://book.pythontips.com/en/latest/map_filter.html

It briefly explains the usage of reduce, as well as map and filter. They are very useful.

read_files = glob.glob("ExampleFile*.json")                                                                                                                                                                         
output_list = []                                                                                                                                                                                                    

for f in read_files:                                                                                                                                                                                                
with open(f, "rb") as infile:                                                                                                                                                                                     
   output_list.append(json.load(infile))                                                                                                                                                                           

final_json = {}                                                                                                                                                                                                                                                                                                                                                                                             
all_items = []                                                                                                                                                                                                      
for json_file in output_list:                                                                                                                                                                                       
   all_items.extend(json_file['items'])                                                                                                                                                                              

final_json['items'] = all_items                                                                                                                                                                                     

textfile_merged = open('merged_json.json', 'w')                                                                                                                                                                     
textfile_merged.write(str(final_json)) 

I suggest you to use json, which is specific for JSON object manipulation. You can do something like this:

    import json

with open('example1.json') as f:
    data1 = json.load(f)

with open('example2.json') as f:
    data2 = json.load(f)

with open('example3.json') as f:
    data3 = json.load(f)

items1 = data1["items"]
#print(json.dumps(items1, indent=2))
items2 = data2["items"]
items3 = data3["items"]

listitem = [items1, items2, items3]
finaljson = {"items" : []}

finaljson["items"].append(items1)
finaljson["items"].append(items2)
finaljson["items"].append(items3)
print(json.dumps(finaljson, indent=2))

with open('merged_json.json', "w") as f:
    f.write(json.dumps(finaljson, indent=2))

where json.load() convert a string to a json object, while json.dumps() convert a json to a string. The parameter indent let you print the object in the expanded way.