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
