python import module Precautions

And from import of difference 1.import

import module import modules: the statement after the implementation will create a new namespace, perform the appropriate function in the namespace. When executed, the variables required before the function and class names need to add  the prefix "module name."

from module import * import modules: a module is defined to be introduced into the current namespace, this time does not need to prefixing.

When the package has:

Import  . package name module name : package name prefix is required module name;

import module name from the package name: the name of the package does not require the use of tape, but need a module name;

. From the package name module name import *: direct use of the function, the variable name can;

2. I found a problem in practice, when import of:

Demo1 import function module in the main file, demo1 the test code also performed? ?

The solution is to add test code modules demo1 IF  __name__ __ == " __main__ " :

__name__ __ == IF "__ main__": 
    Print ( "test code ======") 
    Print "convert RMB:", dollar_convert_to_RMB (50)

Explanation: Each module is a variable __name__, this variable determines which program execution module.

A python file used in two ways, the first direct execution as a script, and the second is to import another python script is called (block reuse) performed. Thus if __name__ == 'main': role is to control the execution of code both cases, if __name__ == 'main': under the code only (i.e., as a script file direct execution) only in the first case It will be executed, and import to other scripts will not be executed.