Next day Python3.4.2 function

1. What is a function

1.1 functions are well-organized, reusable, code snippets that implement a single function

1.2 functions have input (parameter) and output (return value)

1.3 Python, the function is a first-class object (first Clas)

The definition and invocation of a function:

def fn ():   ...     .:pass   ....: in [+]: fn () in [def  fn ():   ....:      Print ('test fn') ....: In     [approx]: fn () test FN

If there is an assignment, create a new variable, without assigning a value, use the value of the original variable.

in [+]: lst=[1,2,3]in [def  Append (item):   .....:     lst.append (item) ...   .: In     [ : Append (4) in[]: lstout[46]: [1, 2, 3, 4]

Next day Python3.4.2 function