In programming languages, functions are the named part of the code. These are separate blocks in the program text. Defined using the reserved word def. In Python, functions can be accessed an unlimited number of times from any part of the script.
Why functions are needed
Functions are an indispensable tool for a programmer. With their help, the developer structures the program, making it clearer and more compact. With the help of functions, it is possible to reuse a separate part of the code without writing it again.
This is the easiest way to package the logic of the execution of individual parts of the program. This reduces the amount and time that a specialist spends on creating a script.
How to write the first function
Python 3 print(). . Python .
«» Python 3. . IDLE . print(«Hello, World!») «». .
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def
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, «Hello, World!», def:
- >>> def _():
- print(«Hello, World!»)
- >>> _() #
- Hello, World!
return
def Python :
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return:
- def <>( 1, 2, N):
- ...
- return <>
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, . , def return. , :
- x = 12 #
- y = 34
- >>>def example(x,y): # example
- x = «Hello» # x, y
- y = «Python»
- print(x, y, sep= «, »)
- return None
- >>>example(x, y) # ,
- Hello, Python
- >>>print(x, y)
- 12 34
. Python print() x y .
, :
- >>>def E_2(x, y):
- return x + y
- >>>E_2(«Hello, » «Python!») # ,
- Hello, Python!
- E_2(5, 4)
- 10
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LEGB
. , , . . notlocal global.
LEGB :
- def, .
- , def.
- , global.
- , Python.
:
- >>>L = 85
- >>>R = 23
- >>>def _2(K):
- R = 10
- C = L + K+R
- return C
- >>>_2(5)
- 100
L R . R, C K – , def.
R, C K, R def. L, local, .
lambda
def, Python , - lambda. - LISP.
def, lambda , , - . lambda , .
-
lambda- def. lambda, , :
- >>>f = lambda x, y, z: x + y + z
- >>>f(2, 3, 4)
- 9
, . lambda def. , while for.
def . , , , – , .
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