python基础(变量，续行符，is，round，if，字符串，日期，数学，参数)

#coding=utf-8
#print函数
print 3, -1, 3.14159, -2.8
#type函数
print type(3), type(3.14159), type("123")
#类型转换
print int(3.14159), int(-2.8)
print float(3), float(-1)
#输出字符串
print "span" + "and" + "eggs"
str1 = "teacher"
str2 = "student"
print "I'm a %s, not a %s"%(str1, str2)
s = "123"
print type(s) == str
#次方
print 3 ** 3
print 81 ** 0.5

一.变量

#coding=utf-8
#变量
meal = 40
tip = 0.5
total = meal * (1 + tip)
print "%.2f"%total

fifth_letter = "MONTY"[4]
print fifth_letter

#正常除，地板除
print 1 / 2.0
print 1 // 2.0

#复数
x = 2.4 + 5.6j
print x.imag
print x.real
print x.conjugate()

二.续行符

#coding=utf-8
#续行符
a = "aaaaaa"\
    "bbbbbbb"
print a
print "---------------"
#(),[],{},'''可以不用续行
a = ("aaaaa"
"bbbbb")
print a
print "---------------"
a = ["aaaaa"
     "bbbbbbb"]
print a
print "---------------"
a = {"aaaaaa"
     "bbbbbbb"}
print a
print "---------------"
a = '''aaaaaaaaa
bbbbbbbbb'''
print a
print "---------------"

三.is，round函数

#coding=utf-8
#is是通过对象id判断
a = 100.0
b = 100
c = 100
print a == b
print a is b
print c is b
print "------------"
#四舍五入
print round(3.4)
print round(3.5)
print "------------"
#函数
def spam():
    eggs = 12
    return eggs
print spam()

四.if结构，函数

if True:
    pass
elif True:
    pass
else:
    pass
#continue,break

print 8 > 4 > 2
print 8 > 4 == 4
print "-----------"

def f(x, y):
    pass
print f(68, False)
print f(y = False, x = 68)
#print f(y = False, 68),error

五.局部全局变量

#coding=utf-8
"""
全局，局部变量
"""
num = 4
def f():
    num = 3
f()
print num #4

def g():
    global num
    num = 3
g()
print num #3

 六.字符串

#coding=utf-8
#字符串
a = "Xsxx"
print len(a)
print a.lower()
print a.upper()
print a.isalpha()
print a.istitle()#首字母大写，其他字母小写s
print a[0]
print a[1:3]
print type(str(3.14))

 

七.键盘输入

#coding=utf-8
#从键盘输入
num = raw_input("what's the number?")

八.日期

#coding=utf-8
#日期
from datetime import datetime
now = datetime.now()
print now
print now.year
print now.month
print now.day
print "%s:%s:%s"%(now.hour, now.minute, now.second)

九.数学

#coding=utf-8
#数学
from math import *
print sqrt(25)
a = [1,2,3,4,5]
print max(a)
print min(a)
print abs(-5)
#print dir(math),error:no math

import math
print dir(math)

十.参数

#coding=utf-8
#参数不确定时，*args,**kwargs(**kwargs有key值)
a = [1, 2, 3, 4]
b = 4
c = '111'

def f(*args):
    for i in args:
        print i
f(a,b,c)

def g(**kwargs):
    print kwargs
g(z = 1, k = 2, l = 3)