2022-11-21 python实例

1.斐波拉契数列

a, b = 0, 1
while b < 10:
    print(b,end=" ")
    a, b = b, a+b

1 1 2 3 5 8

def Fib(n):
    if n == 1 or n == 2:
        return 1
    else:
        return Fib(n-1)+Fib(n-2)
n = int(input("请输入n:"))
a = Fib(n)
print("第n项值为：",a)

请输入n:3
第n项值为： 2

2.数字猜谜游戏

number = 7
guess = -1
print("数字猜谜游戏!")
while guess != number:
    guess = int(input("请输入你猜的数字："))
 
    if guess == number:
        print("恭喜，你猜对了！")
    elif guess < number:
        print("猜的数字小了...")
    elif guess > number:
        print("猜的数字大了...")

3.数学问题

1）数字求和

num1 = input('输入第一个数字：')
num2 = input('输入第二个数字：')
sum = float(num1) + float(num2)    
print('数字 {0} 和 {1} 相加结果为： {2}'.format(num1, num2, sum))

or

print('两数之和为 %.1f' %(float(input('输入第一个数字：'))+float(input('输入第二个数字：'))))

2）求1~100中所有奇数的和、所有偶数的和

num = 1; sub1 = 0; sub2 = 0
while(num <= 100):
    if num % 2 == 0:
        sub2 += num
    else:
        sub1 += num
    num += 1     #while循环不要忘了！！
print("所以奇数和为%d,所以偶数和为%d" % (sub1,sub2))
#>>所以奇数和为2500,所以偶数和为2550   --，没有空格！！

3）.求自然对数的底数e的值，直到最后一项的绝对值小于为止

i = 1; e = 1; t = 1
while (1/t >= pow(10,-6)):     #pow(x,y)表示x的y次方
    t *= i    #t = t*i
    e += 1/t
    i += 1
print("e=",e)

 4）显示100~200不能被3整除的数，要求一行显示10个数

j = 0                 #控制一行显示的数值个数
print("100~200之间不能被3整除的数为：")
for i in range(100,201):
    if i % 3 == 0:
        continue
    print(str.format("{0:<5}",i),end="")     #每个数占5个位置，不足的后面加空格，不换行
    j += 1
    if (j % 10 == 0):
        print()     #换行

4.求圆的周长和面积

import math
r=int(input("请输入圆的半径："))
c=2*math.pi*r
s=math.pi*r**2
print("请输入圆的周长%0.2f和面积%0.2f"%(c,s))

5.声明和调用函数value(b,r,n),根据本金b、年利率r和年数n计算最终收益。

提示：v = b(1+r)**n

def value(b,r,n):
    v = b * ((1 + r) ** n)
    return v
total = value(1000,0.05,5)
print(total)

6.九九乘法表

1）

for i in range(1,10):   #外循环
    s = "" 
    for j in range(1,10):   #内循环
        s += str.format("{0:1} * {1:1} = {2:<3}",i,j,i * j)   #{0:1}表示索引为0,1个字符的长度
    print(s)

1 * 1 = 1  1 * 2 = 2  1 * 3 = 3  1 * 4 = 4  1 * 5 = 5  1 * 6 = 6  1 * 7 = 7  1 * 8 = 8  1 * 9 = 9  
2 * 1 = 2  2 * 2 = 4  2 * 3 = 6  2 * 4 = 8  2 * 5 = 10 2 * 6 = 12 2 * 7 = 14 2 * 8 = 16 2 * 9 = 18 
3 * 1 = 3  3 * 2 = 6  3 * 3 = 9  3 * 4 = 12 3 * 5 = 15 3 * 6 = 18 3 * 7 = 21 3 * 8 = 24 3 * 9 = 27 
4 * 1 = 4  4 * 2 = 8  4 * 3 = 12 4 * 4 = 16 4 * 5 = 20 4 * 6 = 24 4 * 7 = 28 4 * 8 = 32 4 * 9 = 36 
5 * 1 = 5  5 * 2 = 10 5 * 3 = 15 5 * 4 = 20 5 * 5 = 25 5 * 6 = 30 5 * 7 = 35 5 * 8 = 40 5 * 9 = 45 
6 * 1 = 6  6 * 2 = 12 6 * 3 = 18 6 * 4 = 24 6 * 5 = 30 6 * 6 = 36 6 * 7 = 42 6 * 8 = 48 6 * 9 = 54 
7 * 1 = 7  7 * 2 = 14 7 * 3 = 21 7 * 4 = 28 7 * 5 = 35 7 * 6 = 42 7 * 7 = 49 7 * 8 = 56 7 * 9 = 63 
8 * 1 = 8  8 * 2 = 16 8 * 3 = 24 8 * 4 = 32 8 * 5 = 40 8 * 6 = 48 8 * 7 = 56 8 * 8 = 64 8 * 9 = 72 
9 * 1 = 9  9 * 2 = 18 9 * 3 = 27 9 * 4 = 36 9 * 5 = 45 9 * 6 = 54 9 * 7 = 63 9 * 8 = 72 9 * 9 = 81 

2）下三角

①可将1）中的for j in range(1,10)改为for j in range(1,i+1)，其余不变

②

for i in range(1,10):   #外循环
    s = ""
    for j in range(1,i+1):   #内循环
        print("%d * %d = %d"%(i,j,i * j),end="\t")  
    print("")  #表示换行

1 * 1 = 1	
2 * 1 = 2	2 * 2 = 4	
3 * 1 = 3	3 * 2 = 6	3 * 3 = 9	
4 * 1 = 4	4 * 2 = 8	4 * 3 = 12	4 * 4 = 16	
5 * 1 = 5	5 * 2 = 10	5 * 3 = 15	5 * 4 = 20	5 * 5 = 25	
6 * 1 = 6	6 * 2 = 12	6 * 3 = 18	6 * 4 = 24	6 * 5 = 30	6 * 6 = 36	
7 * 1 = 7	7 * 2 = 14	7 * 3 = 21	7 * 4 = 28	7 * 5 = 35	7 * 6 = 42	7 * 7 = 49	
8 * 1 = 8	8 * 2 = 16	8 * 3 = 24	8 * 4 = 32	8 * 5 = 40	8 * 6 = 48	8 * 7 = 56	8 * 8 = 64	
9 * 1 = 9	9 * 2 = 18	9 * 3 = 27	9 * 4 = 36	9 * 5 = 45	9 * 6 = 54	9 * 7 = 63	9 * 8 = 72	9 * 9 = 81	

7.判断一个正整数是否为素数（即质数）

判断一个正整数a是否为素数，只要判断a可否被2~中的任意一个整数整除即可，若不能则a为素数，否则为合数

1）简易：

a = int(input("请输入一个整数："))
if a == 1 or a == 2 or a == 5 or a == 7:
    print("yes")
if a % 2 == 0 or a % 3 == 0 or a % 5 == 0 or a % 7 == 0:
    print("no")
else:
    print("yes")

2）利用for循环和break语句

import math
a = int(input("请输入一个整数(>1)："))
k = int(math.sqrt(a))
for i in range(1,k+2):
    if a % k == 0:
        break
if i == k+1:
    print("yes")
else:
    print("no")

3）利用while循环和bool变量：

import math
a = int(input("请输入一个整数(>1)："))
k = int(math.sqrt(a))
flag = True      #先假设所输整数为素数
i = 2
while (i <= k and flag == True):    #bool类型记得首字母大写
    if (a % i == 0):
        flag = False          #可以整除，肯定不是素数，结束循环
    else:
        i += 1
if (flag == True):
    print("yes")
else:
    print("no")

8.使用continue语句跳过循环。

要求输入若干学生成绩（按Q或q键结束），如果成绩<0，则重新输入。统计学生人数和平均成绩。

num = 0; source = 0    #初始化学生人数和成绩之和
while True:
    s = input("请输入学生成绩（按Q或q键结束）：")
    if s.upper() == "Q":       #.upper() 将字符串小写字母-->大写字母
        break
    if float(s) < 0:        #学生成绩要大于0
        continue
    num += 1
    source += float(s)
print("学生人数为:{0}，平均成绩为:{1}".format(num,source/num))