python基本语法，,语法特点：-----

python基本语法，,语法特点：-----

语法特点：-------------------------------------------------------------
严格的缩进定义变量直接写变量名
没有++ -- && || 代替 and or not
判断条件后需要加：
函数内使用函数外的全局变量需要加global

4种数据类型——整数、长整数、浮点数和复数：---------------------------------------------------------------------
2是一个整数的例子。
长整数不过是大一些的整数。
3.23和52.3E-4是浮点数的例子。E标记表示10的幂。在这里,52.3E-4表示52.3 * 10 -4 。
(-5+4j)和(2.3-4.6j)是复数的例子。
字符串：单引号‘‘ 双引号"" 三引号‘‘‘ ‘‘‘-----------------------------------------------------------------------------
单引号与双引号一样，三引号可以在多行写
字符串与字符串相连：两字符串相邻会自动相加
字符串与变量相连，通过，会自动在两者之间加空格

转义符：\ 同时也是换行符 r或R 忽略转义
------------------------------------------------------------------------------

控制语句：------------------------------------------
for:
----------------------------------------------------------------
number = 23
guess = int(raw_input(‘Enter an integer : ‘))
if guess == number:
print ‘Congratulations, you guessed it.‘ # New block starts here
print "(but you do not win any prizes!)" # New block ends here
elif guess < number:
print ‘No, it is a little higher than that‘ # Another block
else:
print ‘No, it is a little lower than that‘
print ‘Done‘

while:
----------------------------------------------------------------------------------------------
number = 23
running = True
while running:
guess = int(raw_input(‘Enter an integer : ‘))
if guess == number:
print ‘Congratulations, you guessed it.‘
running = False # this causes the while loop to stop
elif guess < number:
print ‘No, it is a little higher than that‘
else:
print ‘No, it is a little lower than that‘
else:
print ‘The while loop is over.‘
for:
----------------------------------------------------------------------------------------------
for i in range(1, 5):
print i
else:
print ‘The for loop is over‘
break:
-----------------------------------
while True:
s = raw_input(‘Enter something : ‘)
if s == ‘quit‘:
break
print ‘Length of the string is‘, len(s)
print ‘Done‘
continue:
-------------------------------------------
while True:
s = raw_input(‘Enter something : ‘)
if s == ‘quit‘:
break
if len(s) < 3:
continue
print ‘Input is of sufficient length‘

函数：
--------------------
函数内使用外部变量加global
默认值直接在参数后用=相连
默认返回None
-----------------------------------
def say(message="hello world"):
print ‘say‘，message
sayHello("hello")
--------------------------
def func(a, b=5, c=10):
print ‘a is‘, a, ‘and b is‘, b, ‘and c is‘, c
func(3, 7)
func(25, c=24)
func(c=50, a=100)------------------------------
def maximum(x, y):
if x > y:
return x
else:
return yprint maximum(2, 3)
模块：----------------每个python脚本都算是一个模块，我们可以在自己的脚本里引入其它模块，这样我们就可以直接使用引入模块的功能了。与java相比，类似于每个python脚本是一个java类，我们在自己的类里面导入别的类,自己定义模块就相当于自己写个类然后在另外一个类文件引入------------------------------------------------------------------------------------------------------------------------#!/usr/bin/python#coding=utf-8 import sys #使用模块 sys模块包含了与Python解释器和它的环境有关的函数print sys.argv-----------------------------------dir()函数：—————-----列出模块内所有的属性和函数

python基本语法