Learn to summarize the basics of--python

First of all, of course, first Hello world!.

Print (' Hello world! ')

Operation Result:

Variable

name = ' Xiaoming ' #定义一个变量

Age = 18

Input (' Please enter your name: ')

Print (name)

Operation Result:

Conditional judgment

#if Else

If 1>2:
Print (' That's impossible ~ ')

Elif 1=2:

Print (' also impossible ~ ')
Else
Print (' Yes! ‘)

String formatting

Import datetime
user = ' Wangjian '
Today = Datetime.datetime.today () # get todays date
# print (type user) output user type
# print (today) output today's type
Today = STR (today) #转换类型
#msg = ' welcome ' +user+ ' presence, today's date is ' +today ' define MSG variable
msg = ' Welcome%s ' login, today's date is \t%s\n '% (user,today) #%s---placeholder; \ n---line break; \ t---whitespace
Print (msg)

#############################################################################################

Age = 18
Score = 98.5326
Print (Round (score,2)) # round () keep several decimal places
msg = ' Your age is%d, your score is%.2f '% (age,score) # String%d integer%f is a decimal. 1 Keep one decimal place,. 2 Reserve two decimal places
Print (msg)

Loop, iterate, iterate

# while

Here, give me a chestnut! Guess number Game ~

Import Random
num = random.randint (1,100) #产生一个1-random number between 100
Count = 0 #定义一个变量用于计数

########## #循环体 ############
While count<7: #最多猜7次
Guess = input (' Please enter the number you guessed: ')
guess = Int (guess)
If guess > num:
Print (' Big up ')
# continue# ends this cycle, loops from the beginning, and does not perform the subsequent count=count+1
Elif Guess < num:
Print (' small ')
　　　　# continue
Else
Print (' Congratulations on your guess right ')
Break #立即结束循环
Count = Count + 1
else: #循环正常结束之后, the else is executed
Print (' Game over ')

########## #循环体 ############

#count +=1
#count-=1 #count = count-1
#count *=1 #count = count*1
#count/=1 #count = COUNT/1

#for

num = 10
For I in range (3):
Guess = input (' Please enter the number you guessed: ')
guess = Int (guess)
If guess > num:
Print (' Big up ')
Elif Guess < num:
Print (' small ')
Else
Print (' Congratulations on your guess right ')
Break #立即结束循环
else: #循环正常结束之后, the else is executed
Print (' Game over ')

List array

List array
Stus = [' Little black ', ' Little white ', ' Little Red ', ' Little Blue ']
# 0 1 2 3
#下标, angle, index, number
Print (Type (stus))
Print (Stus[0])
#增加
Stus.append (' Little black ') #在列表末尾增加一个元素
Print (Stus)
Stus.insert (0, ' little orange ') #在指定位置添加一个元素
Print (Stus)
#删除
Stus.pop (2)#删除指定位置的元素
Print (Stus)
Stus.remove (' Little Red ')#删除指定的元素
Print (Stus)
Del Stus[1]#删除指定位置的元素
Print (Stus) s
#修改
STUS[1] = ' small ash '
Print (Stus)
#查询
Print (Stus[-1])#取值 Subscript-1 takes the last element
Stus.clear ()#清空整个list
Print (Stus.count (' small black '))#统计这个元素在list里面出现了几次
Count = Stus.count (' Little Black ')
Print (count)
Print (Stus.index (' small black '))# Returns the index of the first occurrence of this element, or an error if the element does not exist in the list .
Print (Stus)
Stus.reverse ()#反转
Print (Stus)
Stus2 = [' ingot ', ' and two ', ' egg hemp ']
Print (Stus2+stus)
Stus.extend (STUS2)#把后面list里面的值, add to the first list
Print (Stus)
Stus3=stus+stus2#合并两个list
Print (STUS3)

Nums = [1,3,5,7,9,5,6,7,9,10]
Nums.sort () #排序, the default is ascending
Nums.sort (reverse=true) #降序
Print (Nums)

n = [a] #一维数组
N2 = [[1,2,3],[4,5,6]] #二维数组
my = [
[1,2,3,4,5,6],
[' Name ', ' age ', ' sex ', ' haha ', [' xiaoming ', ' small aperture ', ' Xiao Qiang '],
890
] #三维数组
Print (my) #看变量的元素个数, length
Print (my[1][4][0]) #找小明
My[1][4].append (' Floret ') #在小强后面加一个小花
Print (My[1][4])
my[1][2]= ' sex ' #将sex改为性别
Print (my)

Determine if you are in list: two methods
Username = input (' User: ')
Count = Stus.count (username)
Print (Stus)
If count>0:
Print (' The user already exists ')

Learn to summarize the basics of--python