模块是包含Python定义和语句的文件。一个模块可以定义函数，类和变量。模块也可以包含可运行的代码。将相关代码分组到一个模块中可使代码更易于理解和使用。
示例：
# A simple module, calc.py
def add(x, y):
return (x+y)
def subtract(x, y):
return (x-y) import语句
通过在其他一些Python源文件中执行import语句，我们可以将任何Python源文件用作模块。
当解释器遇到import语句时，如果搜索路径中存在模块，它将导入该模块。搜索路径是解释器搜索以导入模块的目录列表。例如，要导入模块calc.py，我们需要在脚本顶部放置以下命令：
# importing module calc.py
import calc
print add(10, 2) 输出：
12from import语句
Python的from语句可让您从模块中导入特定属性。from .. import ..具有以下语法：
# importing sqrt() and factorial from the
# module math
from math import sqrt, factorial
# if we simply do "import math", then
# math.sqrt(16) and math.factorial()
# are required.
print sqrt(16)
print factorial(6) 输出：
4.0
720dir() 函数
内置的dir()函数返回一个包含由模块定义的名称的字符串排序列表。该列表包含模块中定义的所有模块，变量和功能的名称。
# Import built-in module random
import random
print dir(math) 输出：
['BPF', 'LOG4', 'NV_MAGICCONST', 'RECIP_BPF', 'Random',
'SG_MAGICCONST', 'SystemRandom', 'TWOPI', 'WichmannHill',
'_BuiltinMethodType', '_MethodType', '__all__',
'__builtins__', '__doc__', '__file__', '__name__',
'__package__', '_acos', '_ceil', '_cos', '_e', '_exp',
'_hashlib', '_hexlify', '_inst', '_log', '_pi', '_random',
'_sin', '_sqrt', '_test', '_test_generator', '_urandom',
'_warn', 'betavariate', 'choice', 'division',
'expovariate', 'gammavariate', 'gauss', 'getrandbits',
'getstate', 'jumpahead', 'lognormvariate', 'normalvariate',
'paretovariate', 'randint', 'random', 'randrange',
'sample', 'seed', 'setstate', 'shuffle', 'triangular',
'uniform', 'vonmisesvariate', 'weibullvariate']说明python内置模块的代码段：
# importing built-in module math
import math
# using square root(sqrt) function contained
# in math module
print math.sqrt(25)
# using pi function contained in math module
print math.pi
# 2 radians = 114.59 degreees
print math.degrees(2)
# 60 degrees = 1.04 radians
print math.radians(60)
# Sine of 2 radians
print math.sin(2)
# Cosine of 0.5 radians
print math.cos(0.5)
# Tangent of 0.23 radians
print math.tan(0.23)
# 1 * 2 * 3 * 4 = 24
print math.factorial(4)
# importing built in module random
import random
# printing random integer between 0 and 5
print random.randint(0, 5)
# print random floating point number between 0 and 1
print random.random()
# random number between 0 and 100
print random.random() * 100
List = [1, 4, True, 800, "python", 27, "hello"]
# using choice function in random module for choosing
# a random element from a set such as a list
print random.choice(List)
# importing built in module datetime
import datetime
from datetime import date
import time
# Returns the number of seconds since the
# Unix Epoch, January 1st 1970
print time.time()
# Converts a number of seconds to a date object
print date.fromtimestamp(454554) 输出：
5.0
3.14159265359
114.591559026
1.0471975512
0.909297426826
0.87758256189
0.234143362351
24
3
0.401533172951
88.4917616788
True
1461425771.87
1970-01-06