Python学习100例之41-50

此Python版本为2.7，其他例子如下：
Python学习100例之1-10
Python学习100例之11-20
Python学习100例之21-30
Python学习100例之31-40
Python学习100例之51-60
Python学习100例之61-70
Python学习100例之71-80
Python学习100例之81-90
Python学习100例之91-100

41.模仿静态变量的用法

def varfunc():
    var = 0
    print('var = %d' % var)
    var += 1
    if __name__ == '__main__':
        for _ in range(3):
            varfunc()


class Static:
    StaticVar = 5

    def varfunc(self):
        self.StaticVar += 1
        print(self.StaticVar)


print(Static.StaticVar)
a = Static()
for _ in range(3):
    a.varfunc()
print('\n')

42.学习使用auto定义变量的用法

num = 2


def autofunc():
    num = 1
    print('internal block num = %d' % num)
    num += 1


for _ in range(3):
    print('The num = %d' % num)
    num += 1
    autofunc()
print('\n')

43.模仿静态变量(static)另一案例

class Num:
    nNum = 1

    def inc(self):
        self.nNum += 1
        print('nNum = %d' % self.nNum)


if __name__ == '__main__':
    nNum = 2
    inst = Num()
    for _ in range(3):
        nNum += 1
        print('The num = %d' % nNum)
        inst.inc()
print('\n')

44.两个 3 行 3 列的矩阵，实现其对应位置的数据相加，并返回一个新矩阵

 X = [[12,7,3],
     [4 ,5,6],
     [7 ,8,9]]

 Y = [[5,8,1],
     [6,7,3],
     [4,5,9]]

X = [[12, 7, 3],
     [4, 5, 6],
     [7, 8, 9]]

Y = [[5, 8, 1],
     [6, 7, 3],
     [4, 5, 9]]

Z = []
for i in range(len(X)):
    Z.append([])
    for j in range(len(X[i])):
        Z[i].append(X[i][j] + Y[i][j])
print(Z, '\n')

45.统计 1 到 100 之和。

total = 0
for i in range(1, 100 + 1):
    total += i

print("1 + 2 + 3 + ... + 99 + 100 = %d\n" % total)

46.求输入数字的平方，如果平方运算后小于 50 则退出

while True:
    num = int(input("请输入一个数字:"))
    square = num ** 2
    print("%d² = %d" % (num, square))
    if square < 50:
        break
print('\n')

47.两个变量值互换

def exchange(number1, number2):
    number1, number2 = number2, number1
    return number1, number2


num1 = int(input("请输入一个数:"))
num2 = int(input("请输入一个数:"))
print("%d %d" % (num1, num2))
print("%d %d\n" % exchange(num1, num2))

48.数字比较

def compare(number1, number2):
    if number1 > number2:
        print("%d > %d\n" % (number1, number2))
    elif number1 == number2:
        print("%d = %d\n" % (number1, number2))
    else:
        print("%d < %d\n" % (number1, number2))


num1 = int(input("请输入第一个数:"))
num2 = int(input("请输入第二个数:"))
compare(num1, num2)

49.使用lambda来创建匿名函数

s = lambda x, y: x + y
print(s(1, 2), '\n')

50.输出一个随机数

import random

print(random.random())   输入0-1之间的随机数
print(random.uniform(1, 20))   输出1-20之间的随机数
print(random.randint(1, 20))   输出1-20之间的随机整数