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request.POST.get('sth') vs request.POST['sth'] – difference?

Posted by: admin November 30, 2017 Leave a comment

Questions:

What is the difference between

request.POST.get('sth')

and

request.POST['sth']

Did not find the similar question, both work the same for me, suppose I can use them separately but maybe I am wrong, that is why I am asking. Any ideas?

Answers:

request.POST['sth'] will raise a KeyError exception if 'sth' is not in request.POST.

request.POST.get('sth') will return None if 'sth' is not in request.POST.

Additionally, .get allows you to provide an additional parameter of a default value which is returned if the key is not in the dictionary. For example, request.POST.get('sth', 'mydefaultvalue')

This is the behavior of any python dictionary and is not specific to request.POST.


These two snippets are functionally identical:

First snippet:

try:
    x = request.POST['sth']
except KeyError:
    x = None

Second snippet:

x = request.POST.get('sth')


These two snippets are functionally identical:

First snippet:

try:
    x = request.POST['sth']
except KeyError:
    x = -1

Second snippet:

x = request.POST.get('sth', -1)


These two snippets are functionally identical:

First snippet:

if 'sth' in request.POST:
    x = request.POST['sth']
else:
    x = -1

Second snippet:

x = request.POST.get('sth', -1)

Questions:
Answers:

The main difference between normal dictionaries access and accessing it with .get() is that

With
using something like
request.POST['sth'] will arise a key error is if the ket ‘sth’ does not exist.
But using get() method dictionaries will also provide you with better error handling

request.POST.get('sth')

will return none is the key ‘sth does not exist’
and also by giving the second parameter to get() will return with it as a default value.

data = request.POST.get('sth','my_default_value')

if ‘sth’ key does not exist the value in data will be my_default_value.
That’s the advantage of using get() method over normal dictionaries access.