Python basic study notes 05-function

function

1. Define
def function name (parameter):
function body

2. Multi-function execution flow

a = 100
def test01():
    print(a)
def test02():
    global a	# global关键字代表全局变量
    a = 10
    print(a)

3. Return value

def func(a,b):
    return a,b
print(func(24,23))

Note:
Multiple return value functions return tuples by default and return
can be connected to lists, tuples or dictionaries

4. Parameters
Keyword parameters:
If there are positional parameters, the positional parameters must be before the keyword parameters, but there is no order between the keyword parameters

def func(name,age,gender):
    print(f'姓名：{name},年龄:{age},性别:{gender}')
func('Tom',gender='男',age=20)

Default parameters:
same as default parameters

def func(name,age,gender='男'):
    print(f'姓名：{name},年龄:{age},性别:{gender}')
func('Tom',20,'女')

Variable length parameters:
used in scenarios
where you are not sure how many parameters will be passed when calling. Package location:

def func(*args):
    print(args)
func('Tom',18)

Note: All the parameters passed in will be collected by the args variable, which will be combined into a tuple according to the position of the passed parameters. args is the tuple type, which is the package position transfer

Package keywords:

def func(**kwargs):
    print(kwargs)
func(name='Tom',age=18,gender='man')
# {'name': 'Tom', 'age': 18, 'gender': 'man'}

To sum up: Whether it is package location or package keyword delivery, it is a process of grouping a package