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

Question

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?

Answer 1

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)