ValueError：以10为底的int（）的无效文字：''发送空值时出现此错误

Question

I got ValueError: invalid literal for int() with base 10: '' error. I wrote

def convert_json(request):
    json_body = json.loads(request.body)
    return json_body.get('ans', 0)

When I send json like

{ "ans": "" }  

the error happens.I really cannot understand why this error happens because I think 0 is returned.In this json,"" means None , so 0 should be returned,I think.But my code did not work wells how should i fix this?What should I write it to make ideal system?

Answer 1

In Python, get() will return the value if it exists in the dictionary, even if the value is an empty string.

You can test this by running the following code in your shell:

>>> json_body = {"ans": ""}  
>>> json_body.get('ans', 0)
''

If you want to convert empty strings to 0 , then you should do this in your convert_json method.

def convert_json(request):
    json_body = json.loads(request.body)
    ans = json_body.get('ans', 0)
    if ans == '':
        ans = 0
    return ans

Answer 2

you can chage code to:

def convert_json(request):
    json_body = json.loads(request.body)
    return json_body.get('ans') and int(json_body.get('ans')) or 0

In upper code if ans type wasn't number ValeError raising.