简单讲解Python中的数字类型及基本的数学计算

Python有四种类型的数字：
1.整型

    a = 2 
    print a 

2.长整型

    b = 123456789 
    print b 

3.浮点数

    c = 3.2E2 
    print c 

4.复数 复数为实数的推广，它使任一多项式都有根。复数当中有个"虚数单位"j，它是-1的一个平方根。任一复数都可表达为x+yj，其中x及y皆为实数，分别称为复数之"实部"和"虚部"。

    d = (2+3j) 
    print d 

计算示例：
每种程序语言都有数学计算方法，数学符号通用，大家都知道。直接上代码吧：

    print "I will now count my chickens:" 


    print "Hens", 25 + 30 / 6 
    print "Roosters", 100 - 25 * 3 % 4 


    print "Now I will count the eggs:" 


    print 3 + 2 + 1 - 5 + 4 % 2 - 1 / 4 + 6 


    print "Is it true that 3 + 2 < 5 - 7?" 


    print 3 + 2 < 5 - 7 


    print "What is 3 + 2?", 3 + 2 
    print "What is 5 - 7?", 5 - 7 


    print "Oh, that's why it's False." 


    print "How about some more." 


    print "Is it greater?", 5 > -2 
    print "Is it greatet or equal?", 5 >= -2 
    print "is it less or equal?", 5 <= -2 

运行结果应该是这样的：

    root@he-desktop:~/mystuff# python ex3.py 
    I will now count my chickens:
    Hens 30
    Roosters 97
    Now I will count the eggs:
    7
    Is it true that 3 + 2 < 5 - 7?
    False
    What is 3 + 2? 5
    What is 5 - 7? -2
    Oh, that's why it's False.
    How about some more.
    Is it greater? True
    Is it greatet or equal? True
    is it less or equal? False

eg：用数学计算把英寸和磅转化为厘米和千克。
1英寸 = 2.54厘米，1磅 = 0.4536千克

    my_height_centimeter = my_height * 2.54 
    my_weight_kilo = my_weight * 0.4536 
    print "He's %d centimeters tall." % my_height_centimeter 
    print "He's %d kilos heavy." % my_weight_kilo