0x02-python-import_modules

0x02. Python - import & modules

About

An introductory project on:

• How to import functions from another file
• How to use imported functions
• How to create a module
• How to use the built-in function dir()
• How to prevent code in your script from being executed when imported
• How to use command line arguments with your Python programs

Requirements

• Python 3.4
• pep8 1.7

File Descriptions

Mandatory

0-add.py - imports the function def add(a, b): from the file add_0.py and prints the result of the addition 1 + 2 = 3

• should not be executed when imported

1-calculation.py - imports functions from the file calculator_1.py and uses all of its functions

• should not be executed when imported

2-args.py - prints the number of and the list of its arguments.

• The output should be:
  • Number of argument(s) followed by argument or arguments, followed by
  • : (or . if no argument where passed) followed by
  • a new line, followed by (if at least one argument)
  • one argument per line:
    • the position of the argument (starting at 1) followed by :, followed by the argument value and a new line
• should not be executed when imported

3-infinite_add.py - prints the result of the addition of all arguments

• should not be executed when imported

4-hidden_discovery.py - prints all the names defined by the compiled module hidden_4.pyc

• print only names that do not start with __
• should not be executed when imported

5-variable_load.py - imports the variable a from the file variable_load_5.py and prints its value.

• should not be executed when imported

Advanced

100-my_calculator.py - imports all functions from the file calculator_1.py and handles basics operations.

• Usage: ./100-my_calculator.py a operator b
• If the number of arguments is not 3, your program has to:
• print Usage: ./100-my_calculator.py <a> <operator> <b> followed with a new line
• exit with the value 1
• operator can be:
• + for addition
• - for subtraction
• * for multiplication
• / for division
• If the operator is not one of the above:
• print Unknown operator. Available operators: +, -, * and / followed with a new line
• exit with the value 1
• You can cast a and b into integers by using int() (you can assume that all arguments will be castable into integers)
• The result should be printed like this: <a> <operator> <b> = <result>, followed by a new line
• You are not allowed to use * for importing or __import__
• Your code should not be executed when imported

101-easy_print.py - prints #pythoniscool, followed by a new line, in the standard output.

• Your program should be maximum 2 lines long
• You are not allowed to use print or import sys in your file 101-easy_print.py

102-magic_calculation.py - Write the Python function def magic_calculation(a, b): that does exactly the same as the following Python bytecode:

  3           0 LOAD_CONST               1 (0)
              3 LOAD_CONST               2 (('add', 'sub'))
              6 IMPORT_NAME              0 (magic_calculation_102)
              9 IMPORT_FROM              1 (add)
             12 STORE_FAST               2 (add)
             15 IMPORT_FROM              2 (sub)
             18 STORE_FAST               3 (sub)
             21 POP_TOP

  4          22 LOAD_FAST                0 (a)
             25 LOAD_FAST                1 (b)
             28 COMPARE_OP               0 (<)
             31 POP_JUMP_IF_FALSE       94

  5          34 LOAD_FAST                2 (add)
             37 LOAD_FAST                0 (a)
             40 LOAD_FAST                1 (b)
             43 CALL_FUNCTION            2 (2 positional, 0 keyword pair)
             46 STORE_FAST               4 (c)

  6          49 SETUP_LOOP              38 (to 90)
             52 LOAD_GLOBAL              3 (range)
             55 LOAD_CONST               3 (4)
             58 LOAD_CONST               4 (6)
             61 CALL_FUNCTION            2 (2 positional, 0 keyword pair)
             64 GET_ITER
        >>   65 FOR_ITER                21 (to 89)
             68 STORE_FAST               5 (i)

  7          71 LOAD_FAST                2 (add)
             74 LOAD_FAST                4 (c)
             77 LOAD_FAST                5 (i)
             80 CALL_FUNCTION            2 (2 positional, 0 keyword pair)
             83 STORE_FAST               4 (c)
             86 JUMP_ABSOLUTE           65
        >>   89 POP_BLOCK

  8     >>   90 LOAD_FAST                4 (c)
             93 RETURN_VALUE

 10     >>   94 LOAD_FAST                3 (sub)
             97 LOAD_FAST                0 (a)
            100 LOAD_FAST                1 (b)
            103 CALL_FUNCTION            2 (2 positional, 0 keyword pair)
            106 RETURN_VALUE
            107 LOAD_CONST               0 (None)
            110 RETURN_VALUE

103-fast_alphabet.py - prints the alphabet in uppercase, followed by a new line.

• Your program should be maximum 3 lines long
• You are not allowed to use:
  • any loops
  • any conditional statements
  • str.join()
  • any string literal
  • any system calls