Learning Python Chapter 4 custom functions

Def keywordThe custom function starts with the def keyword followed by the function name, No {} in C #. End the function in indent mode.  In python, user-defined functions must be written before the call statement. (Compilation seems to be compiled from top down) Functions with ParametersFor a function with parameters, directly write the parameter name. If the parameter type is not required, the Data Type Def funname (arg1, arg2) of the input parameter is automatically recognized ): print ("custom function output information") print (arg1) print (arg2 + 1) funname ('parameter 1 information', 123) input () Function with reverse return valueYou do not need to set the type of the reverse return value. The default parameter can be directly equal to the value followed by the default value. Def funname (arg1 = 10): Return arg1n = funname () print (N) N = funname ('12') print (n) n = funname (12) print (n) input () Import reference and namespaceAfter the import, there is no namespace for the file name. The namespace is the file name sub-