Python while, for loop, list of lists

1. While loop (loops can also be called iterations, traversal)

A while loop must have a counter

Count=0

While count<10:

Print (' Hello ')

Count=count+1

2. Guess the number game example

Import Random #引用随机数模块
Num=random.randint (1,100) #随机产生一个数字, 1 to
count=0
print (num)
While count<7:
guess=input (' Please enter the number you guessed: ')
Guess=int (guess)
if Guess>num:
print (' Guess big ')
Continue
elif Guess<num:
print (' Guess small ')
Continue
Else:
print (' Congratulations on your guess right ')
Break #立即结束循环
count=count+1
Else:
print (' Run out of money, please recharge ')

3,count=count+1 equivalent to count+=1(+ 、-、 *,/the same wording)

4, Breakpoint: Click on the front of the statement, a small red dot, using debug run.

5. For loop　　

num=10
For i in range: #表示循环10次
guess = input (' Please enter the number you guessed: ')
guess = int (guess)
if guess > num:
print (' Guess big ')
elif guess < num:
print (' Guess small ')
Else:
print (' Congratulations on your guess right ')
Break # immediate End loop
Else:
print (' Run out of money, please recharge ')

6. The difference between break and continue:

Break is the immediate end of the bounce loop, continue is the end of the current loop into the next loop.

7, List (array)

stus=[' Saki ', ' Yuri ', ' MIMO ' #定义数组

Subscript (angle, index, number) 0 1 2

Stus[0] means Saki stus[1] represents Yuri, subscript starting from 0

8, list additions and deletions to check

# Add
 stus.append (' Sami ') #在列表末尾增加一个元素
 stus.insert (0, ' Kumi ')#在指定位置添加一个元素
# Delete
 Stus.pop (2)#删除指定位置的元素
 del stus[3]#删除指定位置的元素
 stus.remove (' Saki ')#删除指定的元素
 stus.clear ()#清空整个list
# Modify
stus[2]= ' Miumiu '
# Check
 Print (stus[2]) #查询取下标
 Print (stus[-1]) #查询list最后一个元素
 stus.count ()#统计这个元素在list里面出现了几次
 Print (Stus.index (' Saki '))#返回这个元素第一次出现的下标, if the element does not exist, an error will be
 stus.reverse ()#反转列表
print (Stus)
stus2=[' Yuri ', ' Yuro ', ' Yumi ']
 stus.extend (stus2) #把后面list里面的值加入到第一个list里面
 stus3=stus+stus2 #合并两个list
print (Stus)

9. List sort

NUMS=[12,33,11,55,19,25,88]

Nums.sort () # Default Ascending

Nums.sort (reverse=true) #降序

10, three-dimensional array:

my=[

[1,2,3,4,5],

[' Name ', ' age ', ' sex ', [' Saki ', ' Mimo ', ' Yuri '],

890]

Three-dimensional array fetch mimo:my[1][3][1]

11. Two-dimensional array: my[[1,2,3,4,5],[' name ', ' age ', ' sex ']

print (my) #取数组长度

12. Whether the user exists

Username=input (' User: ')

Method 1:

Count=stus.count (username)

If count>0:

Print (' User already exists ')　　

Method 2:

If username in Stus:

Print (' User already exists ')

If username not in Stus:

Print (' User not present ')

Python while, for loop, list of lists