Appending object to array

[Busby]

I'm trying to append objects to an array with the following code

 model_array = [model 1, model 2, model 3] json_array = [] model_data = {} X = len(model_array) Y = 0 while Y != X: model_data["label"] = 'Model No' model_data["value"] = model_array[Y] json_array.append(model_data) Y = Y + 1 print(json_array) 

The output of the json_array is

Output:
{ label : Model No value : model 3 } { label : Model No value : model 3 } { label : Model No value : model 3 }

Can anybody tell me why the json_array only lists model 3 and not the other models

[Yoriz]

The same dictionary is being added to the list 3 times.
Note line 1 is not valid code.

[deanhystad]

As Yoriz says, you are adding the same dictionary each time. If you were to do this:

for thing in json_array: print(id(thing))

It would print the same ID for each item. So when you change the contents of "model_data" the last time through the loop, that is what shows up as values for each (each and only) thing in json_array.

To get different contents you need to make different containers.

model_array = [model_1, model_2, model_3] json_array = [] X = len(model_array) Y = 0 while Y != X: model_data["label"] = 'Model No' model_data["value"] = model_array[Y] json_array.append({'label':'Model No', 'value':model_array[Y]}) # New dictionary each time Y = Y + 1 print(json_array)

But this is awkward code and can be done in a cleaner, shorter and more efficient way.

model_array = [model_1, model_2, model_3] json_array = [] for model in model_array: json_array.append({'label':'Model No', 'value':model}) print(json_array)

Or even as a list comprehension

model_array = [model_1, model_2, model_3] json_array = [{'label':'Model No', 'value':model} for model in model_array] print(json_array)