Python 第一次作业

B=b'China\nhello\tworld!\n'
print(B)
s=B.decode()
print(s)

print(s.encode())

print(s)

b'China\nhello\tworld!\n'
China
hello	world!

b'China\nhello\tworld!\n'
China
hello	world!

A=' hello world  ';

print("A =",A)

print(A.strip())

print(A.lstrip())

print(A.rstrip())

A =  hello world  
hello world
hello world  
 hello world

A='joob centrol south university'

print(A.lower())

print(A.upper())

print(A.capitalize())

joob centrol south university
JOOB CENTROL SOUTH UNIVERSITY
Joob centrol south university

print(A.startswith('joo'))

print(A.endswith('sity'))

B=A.split(' ')

print(B)

C=','.join(B)

print(C)

print(list(reversed(C)))

True
True
['joob', 'centrol', 'south', 'university']
joob,centrol,south,university
['y', 't', 'i', 's', 'r', 'e', 'v', 'i', 'n', 'u', ',', 'h', 't', 'u', 'o', 's', ',', 'l', 'o', 'r', 't', 'n', 'e', 'c', ',', 'b', 'o', 'o', 'j']

单词反转（必须保留空格）

def reverse(new_str,start,ends):

    while start<ends:

        new_str[start],new_str[ends]=new_str[ends],new_str[start]

        start=start+1

        ends=ends-1

​

#str=' I love china!   '

str = ' Hello, how are you?   Fine.   '

new_str=list(str)

new_str=list(reversed(str))

print(new_str)

i=0

while i < len(new_str):

    if new_str[i] != ' ':

        start=i

        ends=start+1

        while ends<len(new_str) and new_str[ends] !=' ':

            ends=ends+1

        reverse(new_str,start,ends-1)

        #print("new_str",new_str)

        i=ends

    else:

        i=i+1

print(new_str)

print("----------------")

#new_str.reverse()

print(''.join(new_str))

[' ', ' ', ' ', '.', 'e', 'n', 'i', 'F', ' ', ' ', ' ', '?', 'u', 'o', 'y', ' ', 'e', 'r', 'a', ' ', 'w', 'o', 'h', ' ', ',', 'o', 'l', 'l', 'e', 'H', ' ']
[' ', ' ', ' ', 'F', 'i', 'n', 'e', '.', ' ', ' ', ' ', 'y', 'o', 'u', '?', ' ', 'a', 'r', 'e', ' ', 'h', 'o', 'w', ' ', 'H', 'e', 'l', 'l', 'o', ',', ' ']
----------------
   Fine.   you? are how Hello, 

打印素数

import time 

​

def prim(n):

    num=[]

    i=2

    for i in range(2,n+1):

        for j in range(2,i):

           # print(j)

            if i%j == 0:

                break

        else:

            num.append(i)

            #print(i)

    return num

'''

L=prim(100)

print(L)

'''

​

t0=time.time()

L=prim(100)

t1=time.time()

print("hh",t1-t0)

print(L)

hh 0.0
[2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97]

import math

import time 

​

def prim(n):

    num=[]

    i=2

    for i in range(2,n+1):

        for j in range(2,int(math.sqrt(i))+1):

           # print(j)

            if i%j == 0:

                break

        else:

            num.append(i)

            #print(i)

    return num

​

​

t0=time.time()

L=prim(100)

t1=time.time()

print("hh",t1-t0)

print(L)

hh 0.0
[2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97]

支持可变参数

def test_arg(name,*key1,**key2):

    print(name)

    print(key1)

    print(key2)

test_arg('zg',12,4,3,'S',china='BJ',UK='LD')

test_arg('xd',*('xz',3,'cdxs'),**{'china':'BJ','UK':'LD'})

zg
(12, 4, 3, 'S')
{'china': 'BJ', 'UK': 'LD'}
xd
('xz', 3, 'cdxs')
{'china': 'BJ', 'UK': 'LD'}

汉诺塔问题

def hanoi(n,A,B,C):

    if(n<1):

        raise ErrorValue

    elif n==1:

        print(A,'-->',B)

    else:

        hanoi(n-1,A,C,B)

        print(A,'-->',B)

        hanoi(n-1,C,B,A)

​

hanoi(3,'A','B','C')

​

A --> B
A --> C
B --> C
A --> B
C --> A
C --> B
A --> B

print(len([1,3,4,5]))

4

冒泡法排序

import random

​

def MaopaoSort(nums,des='asc'):

    l=len(nums)

    flag=1

    i=0

    j=l-1

    while i<l and flag==1:

        flag=0

        j=l-1

        while j>i:

            if des =='asc':

                #print(j)

                if nums[j]<nums[j-1]:

                    nums[j],nums[j-1]=nums[j-1],nums[j]

                    #print(nums[j])

                    flag=1

            else:

                if nums[j]>nums[j-1]:

                    nums[j],nums[j-1]=nums[j-1],nums[j]

                    flag=1

            j=j-1

        i=i+1

        #print(nums)

    print("time :",i)

    return nums

​

L=[random.randint(0,100) for _ in range(10)]

LL=[random.randint(0,100) for _ in range(10)]

print(L)

L1=MaopaoSort(L)

print(L1)

print(LL)

L2=MaopaoSort(LL,'desc')

print(L2)

[76, 41, 21, 50, 96, 8, 87, 83, 44, 53]
time : 7
[8, 21, 41, 44, 50, 53, 76, 83, 87, 96]
[83, 0, 88, 90, 41, 0, 39, 15, 70, 63]
time : 8
[90, 88, 83, 70, 63, 41, 39, 15, 0, 0]