[英]How do I implement a lambda function inside a dict/set/list
So I am coding a user-input system that can accept commands.所以我正在编写一个可以接受命令的用户输入系统。 Further detail on it won't be revealed.
关于它的更多细节不会被透露。
One of the things I want to do is implement a lambda function inside a dictionary.我想做的一件事是在字典中实现 lambda function 。
Here's an example of what I want to do:这是我想做的一个例子:
dictionary = {
"command_a": lambda:
stuff_to_do = ""
# do stuff
return stuff_to_do
}
And when the user enters `command_a', it'd call the function, as follows:当用户输入 `command_a' 时,它会调用 function,如下:
command = input("Command")
if command in dictionary.keys():
dictionary[command]()
But I get:但我得到:
File "<stdin>", line 5
stuff_to_do = ""
^
SyntaxError: invalid syntax
The code seems logical.代码似乎合乎逻辑。 The dictionary stores a function under the "command_a" key, but it doesn't work.
字典在“command_a”键下存储了一个 function,但它不起作用。 Is it permissible to do so in python?
在 python 中是否允许这样做? If yes, then how to?
如果是,那怎么办?
A lambda
can only define a function in the form of a single expression, eg:一个
lambda
只能以单个表达式的形式定义一个 function,例如:
dictionary = {
"command_a": (lambda: "stuff to do")
}
If you want to define a function that consists of multiple statements, you need to use a def
statement:如果要定义一个包含多个语句的 function ,则需要使用
def
语句:
def command_a():
stuff_to_do = ""
# do stuff
return stuff_to_do
dictionary = {
"command_a": command_a
}
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