python3.0
1. List
a = ['1','2','3','4','5',]
2. Find (there are three commands) (indexes start from 0)
1. .count #refers to the number of times an element appears in the list
a.count('2')
print(a) # ==> 2
2. .index #Find its corresponding position according to the subscript
a.index(2)
print(a) # ==>'3'
3. Determine whether an element is in the list a
'6' in a # ==> Flase
3. Increase (there are three commands)
1. a.append() #Append command
a.append(6)
print(a) # ==>a = [1,2,3,4,5,6]
2. a.insert() #You can insert elements at any position in the list
a.insert(2,5)
print(a) # ==>a = [1,2,5,3,4,5]
3、 a.hears
Fourth, modify (there are two commands)
1. a[index] = "new value"
a[1] = 9
print(a) # ==>a = [1,9,5,3,4,5]
2、 a[start:end] =[a, b ,c]
a[1:4] = ['a', 'b', 'c']
print(a) # ==>a = [1,'a','b','c',4,5]
a[1:4] = ['a', 'b']
print(a) # ==>a = [1,'a','b',4,5] #If the input list is inconsistent with the number of sliced lists, only the inserted list will be displayed, and the remaining list of the slice will be empty
5. Delete
1、 remove()
a.remove(5) #Enter the value, find the first element and delete it
print(a) # ==>a = [1,2,3,4]
2. pop(index) #Enter the subscript
a.pop(0)
print(a) # ==>a = [2,3,4,5]
3 a of a ； of a [index]
del a # delete the entire list
del a[index] #delete an element in the array
4. clear() to clear
a.clear()
print(a) # ==>a = []
6. Sort
1. sort() #Sort in ascending order
a.sort()
print(a) #==>a = [1,2,3,4,5]
2. reverse() #Reverse the head and end of the list
a.reverse()
print(a) #==>a = [5,4,3,2,1]
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To sort in descending order
a.sort(reverse = True)
print(a)
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7. Identity judgment
type(a) is list #==> True