Get (“某事物”) vs request. POST [‘某事物’]-差异？

有什么区别

request.POST.get('sth')

还有

request.POST['sth']

没有发现类似的问题，两者对我来说工作相同，假设我可以使用它们分开，但也许我是错的，这就是为什么我问。有什么想法吗？

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最佳答案

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)
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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.

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Request.POST Example

req.POST['name_your_desired_field']

This will throw a KeyError exception if 'name_your_desired_field' is not in req.POST.

request.POST.get('name_your_desired_field')

This will return None if 'name_your_desired_field' is not in req.POST.

Although, .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,

req.POST.get('name_your_desired_field', 'your_default_value')

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

Request.GET Example

request.GET.get('name_your_desired_field')

This will return None if 'name_your_desired_field' is not in req.GET.

Allthough, .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,

req.GET.get('name_your_desired_field', 'your_default_value')

This is the behavior of any python dictionary and is not specific to req.GET


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