One. Define and use functions
1. Definition: The function is a piece of code,
- having a specific function is a period function, reusable statement group
- a feature function is abstract, usually expressed as a function specific functions
- two effects: reduce the difficulty of programming and code reuse
DEF <function name> (<parameter (0 or more)>):
<Function> The
return <Return value>
After calling the function definition without going through it is not performed.
2. Call: Run the function code of way
- To give the actual parameters when calling
- actual parameters defined in the substitution parameters
- After the return value of the function call to get
3. The transfer function parameters
1. The number of parameters, may also be a plurality of 0, but it must retain the brackets
2. optional parameter: you can specify default values for certain parameters defined, optional configuration parameters
3. Variable transmission parameters: the number of variable parameters may be designed to function definition, neither the total number of parameters determined
4. The parameters passed in two ways: position transfer / transmission name
4. Local and global variables
Rule 1: Local and global variables are different variables
- local variables inside a function placeholder with the same name but a different global variables may
- After the calculation function, local variables is released
- You can use the reserved word global use global variables inside a function
Rule 2: Create a local variable and not as a combination of data types, the global variable is equivalent to
Compared:
5.lambda function: anonymous function, no function name. A simple definition, the function can be represented in a row
Second, recursive function code reuse and
Code reuse: the code as abstract resources. It can be reused when necessary
Recursively defined: the definition of the function calls itself a function of ways, such as:
