发布数据时如何检查名称/值对是否存在？ [英] How to check if a name/value pair exists when posting data?

问题描述

我无法找到执行所需操作的正确语法。如果不存在名称/值对，我想做些事情。这是我认为的代码：

I'm not able to find the proper syntax for doing what I want to do. I want to do something if a name/value pair is not present. Here is the code in my view:

if (!request.POST['number']):
    # do something

完成上述工作的正确方法是什么？尝试此操作时遇到语法错误。

What is the proper way to accomplish something like the above? I am getting a syntax error when I try this.

推荐答案

@Thomas为您提供了通用方法，但是有一个快捷方式

@Thomas gave you the generic way, but there is a shortcut for the particular case of getting a default value when a key does not exist.

number = request.POST.get('number', 0)

这等效于：

if 'number' not in request.POST:
    number = 0
else:
    number = request.POST['number']

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