Python Functional Programming--anonymous function lambda

1.1   Anonymous Functions

Sometimes it is easier to pass in anonymous functions without explicitly defining a function.

>>> list (map (Lambda x:x*x, (1, 2, 3, 4, 5))

[1, 4, 9, 16, 25]

before the colon x represents a function parameter .

there is a limit to the anonymous function, that is, there can be only one expression , without writing return, the return value is the result of that expression.

>>> f = Lambda x:x * x

>>> F (2)

4

>>> def build (x, y):

... return x * x + y * y

...

>>> Build (2, 4)

20

>>> def build (x, y):

... return lambda:x * x + y * y

...

>>>

>>> Build (2, 4)

<functionbuild.<locals>.<lambda> at 0x2b8091d87598>

>>> Build (2,4) ()-- call -->lambda again

20

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Python Functional Programming--anonymous function lambda