python习题解析，,1.打印10以内偶数

python习题解析，,1.打印10以内偶数

for i in range(10):        if not i & 0x01:                print(i)

2.给定一个不超过5位的正整数，判断其有几位（使用input函数）

方法一：正常逻辑处理

a = int(input("Please enter a numer: "))if a < 0:        print(‘Error‘)if a < 10:        print(1)elif a < 100:        print(2)elif a < 1000:        print(3)elif a < 10000:        print(4)elif a < 100000:        print(5)else:        print(‘Error‘)

方法二：折半

val=input("Please enter a numer: ")val=int(val)if val>=1000:        if val>=10000:                print("这是五位数")        else:                print("这是四位数")else:        if val>=100:                print("这是三位数")        elif val>=10:                print("这是两位数")        else:                print("这是一位数")

方法三：字符串处理

a = str(int(input("Please enter a number: ")))print(len(a))

3.给定一个不超过5位的正整数，判断该数的位数，依次打印出个位、十位、百位、千位、万位的数字

方法一：

val=input(‘>>>‘)      val=int(val)print(val)if val>=1000:        if val>=10000:                num=5        else:                 num=4else:                   if val>=100:                num=3        elif val>=10:                num=2        else:                 num=1print(num)pre=0for i in range(num,0,-1):        cur=val//(10**(i-1))        print(cur-pre*10)        pre=cur

方法二：

num =int(input("请输入一个数字："))print(num)countnum=0while True:        print(num%10)        num=num//10        countnum+=1        if num==0:                break

print("您输入的位数是：",countnum)
方法三：

c=int(input(">>>"))w=10000x=lengthflag =Falsewhile w:        t=c//w        if flag:                print(t)        else:                if t:                        print(t)                        flag=True                else:                        x -= 1        c %= w        w//=10print("这个数的位数是",x)

4.打印一个边长为n的正方形

方法一：

a = int(input("Please enter a number: "))for i in range(a):        if i == 0 or i == a-1:                print(‘*‘ * a )        else:                print(‘*‘ + ‘ ‘ * (a - 2) + ‘*‘)

方法二：

a = int(input("Please enter a number: "))print(‘*‘ * a)for i in range(a - 2):        print(‘*‘ + ‘ ‘ * (a - 2) + ‘*‘)else:print(‘*‘ * a)

方法三：

a = int(input("Please enter a number: "))top = mid = ‘*‘for i in range(a - 1):        top += ‘\t*‘        mid += ‘\t‘else:        mid += ‘*‘        print(top)for i in range(a - 2):        print(‘\n‘)        print(mid)else:        print(‘\n‘)        print(top)

5.求100内所有奇数的和（2500）

sum = 0for i in range(1,100,2):        sum += iprint(sum)    

6.判断学生成绩，成绩等级A~E。其中，90分以上为‘A‘，80~89分为‘B‘，70~79分为‘C‘，60~69分为‘D‘，60分以下为‘E‘

a = int(input(‘Please enter a score: ‘))if a > 79:        if a >= 90:                print(‘A‘)        else:                print(‘B‘)elif a >= 70:        print(‘C‘)elif 60 <= a < 69:        print(‘D‘)else:        print(‘E‘)

7.求1到5阶乘之和

方法一：

sum = 0for i in range(1,6):        mul = 1        for j in range(1,i + 1):                mul *= j        sum += mulprint(sum)

方法二：效率高

sum = 0mul = 1for i in range(1,6):        mul *= i        sum += mulprint(sum)

8.求圆的面积和周长

r=int(input(">>>"))print("area="+str(3.14*r*r))print("circumference="+str(2*3.14*r))

9.输入若干个数，打印出最大值，如果输入为空，退出程序
m = int(input(">>>"))
while True:
c = input(">>>")
if c:
n = int(c)
if n > m :
m = n
print("max is",m)
else:
break

10.输入n 个数 求每次输入的算术平均数。

count = 0sum = 0while True:    num = int(input(">>>"))    count += 1    sum += num    print("avg is ",sum / count)    if num == 0:            break

11.给一个数，判断它是否是素数（质数）

a=int(input("Please enter a number: "))for i in range(2,int(a ** 0.5) + 1):        if a % i != 0:                continue        elif a % i == 0:                print(("N: %d") % (i))                break        else:        print("Yes,prime")

12.打印九九乘法表

方法一：

for i in range(1,10):        line = ‘‘        for j in range(1,i + 1):                line = line + (‘%d*%d=%2d ‘) % (j,i,i*j)        print(line)

方法二：列表解析式

[print("{}*{}={:<3}".format(j,i,i*j),end=‘\n‘ if i ==j else ‘‘) for i in range(1,10) for j in range(1,i+1)]

13.打印菱形

方法一：

for i in range(-3,4):        if i<0:                prespace=-i        else:                prespace=i        print(‘ ‘*prespace + ‘*‘*(7-prespace*2))

方法二：

n =int(input(">>>"))e = n//2for i in range(-e,e+1):        if i < 0 :                p = -i        else:                p =i        print(" "*p+ "*"*(n-2*p))

14.打印闪电图形
方法一：

for i in range(-3,4):        if i<0:                print(‘ ‘*(-i) + ‘*‘*(4+i))        elif i>0:                print(‘ ‘*3 + ‘*‘*(4-i))        else:                print(‘*‘*7)

方法二：

n =int(input(">>>"))e = n//2for i in range(-e,e+1):        if i < 0 :                print(" "*(-i)+‘*‘*((e+1)+i))        elif i > 0:                print(" "*e + ‘*‘*((e+1)-i))        else:                print("*"*n)

15.打印对顶三角形
方法一：

for i in range(-3,4):        x = -i if i < 0 else i        print(" "*(3-x)+"*"*(2*x+1))

方法二：

n =int(input(">>>"))e = n//2for i in range(-e,e+1):        x = -i if i < 0 else i        print(" "*(e-x)+"*"*(2*x+1))

16.打印100以内的斐波那契数列

a=0b=1print(1)while True:        c=a+b        if c>100:                break        a=b        b=c        print(c)

17.求斐波那契数列第101项 573147844013817084101
方法一：
a = 0
b = 1
print(0,a)
print(1,b)
index = 2
while True:
c = a + b
print(index,c)
if index == 101:
break
a = b
b = c
index += 1

方法二：

a = 0b = 1for _ in range(100):        a, b = b , a+bprint(b)

18.求10万内的所有素数 9592

方法一：（先简单化）

for x in range(2,100):        for i in range(2,x):                if x%i==0:                        break        else:                print(x,end=" ")

方法二：

for x in range(3,10000,2):        for i in range(3,int(x**0.5)+1):                if x%i==0:                        break        else:                print(x,end=" ")

方法三：

import timestart= time.clock()number = 100000count = 2for num in range(4,number):        if num%6 != 1 and num%6 != 5:                continue        else:                snum = int(num**0.5+1)                for i in range(5,snum):                        if not num%i:                                break                else:                        count += 1print(count)end=time.clock()print("run:{}".format(end-start))

方法四：（利用素数特性：大于3的素数形式都是6N-1和6N+1）

import timestart= time.clock()number = 100000count = 2for num in range(4,number):        if num%6 != 1 and num%6 != 5:                continue        else:                snum = int(num**0.5+1)                for i in range(5,snum):                        if not num%i:                                break                else:                        count += 1print(count)end=time.clock()print("run:{}".format(end-start))

19.反向乘法表：

方法一：

for i in range(1,10):        line = ‘‘        for j in range(i,10):                        line += ‘%d*%d=%2d ‘ % (i,j,j * i)        print(‘ ‘ * (7 * i - 6) + line)

方法二：

for i in range(1,10):        line = ‘‘        for j in range(i,10):                        line += ‘%d*%d=%2d ‘ % (i,j,j * i)        print(‘{:>63}‘.format(line))

方法三：

for i in range(1,10):        line = ‘‘        for j in range(i,10):                        line += ‘{}*{}={:<{}} ‘.format(i,j,j * i,2 if j<4 else 3)        print(‘{:>70}‘.format(line))

20.猴子吃桃：

n=1for i in range(1,10):        n=(n+1)*2print(n)

python习题解析