Python is not a road _ a first-level function, and python is not a road to first-level functions

Python is not a road _ a first-level function, and python is not a road to first-level functions

What is a function?

Functions are organized and reusable, and used to implement a single, or associated function code segment. Functions can improve the app's vigilance and reuse of code. You already know that Python provides many built-in functions, such as print (). But you can also create a function by yourself, which is called a user-defined function.

Python Function Format:

1 def func1 (): # Use def to define a function in python. Function Name: func1 () 2 ''' this is test1''' # function explanation. You can use help (func1) command to view func1 function description 3 print ('test1') # function execution statement 4 return 0 # return Value, the function must have a return value, no return value, it is not a function, it is a process.

Note that a function must have a return value. If there is no return value, it is not a function. It is a process. Return can return multiple values and multiple data types. All values are packaged as elements. If no return is returned, the return value is none.

def fun1():    print('test1')    return 1,abc,[1,23,asd,],{'name':'gally-jiang'}
x = fun1()
print('x')

Code Result (1, abc, [1, 23, asd,], {'name': 'gally-jiang '})

 

def fun1():    print('test1')x = fun1()print('x')

Code result none

Parameters

Parameters:

Real parameter: literal explanation, actual, specific value Parameter

Def func1 (x, y): # x, y is the form parameter x = 5 # x = 5 is the real parameter y = 6 # y = 6 is the real parameter print (x, y) return 1

Location Parameter: each value corresponds to a location of the parameter.

def func1(x,y)    print(x,y)func1(1,2)

Output result 1 and 2.

Default parameter: the parameter of the default value.

Def func1 (x, y = 2): # The default value of y is 2 a = x ** y print (a) return 1.

 

Variable Parameter (tuples): this parameter is used when the number of parameters cannot be confirmed. It is represented by * and the output result is tuple.

Def func1 (* args): print (args) func1 (1, 56, 'gally ', '7 ')
Output result (, 'gally ', '7'), which is a ancestor tuple

Variable Parameter (dictionary): the parameter is represented in a dictionary and is represented.

Def func2 (** kvargs): print (kvargs) func2 (name = 'gally ', age = '23') output result {'name': 'gally ', 'age': 23}. The output result is the dictionary dict.

 

Function declaration parameter sequence: required functions> default functions> variable functions (tuples *)> variable functions (Dictionary **)

------- O & M that won't be developed is not a good cook