List of Python3 and Python3

List of Python3 and Python3

1: List:

Python lists are much more powerful than C-language arrays. Arrays can only store the same type of data, while lists are like a large container that can store shaping, float, String, object, etc.

2: Create a list

# Create a common list1 = [1, 2, 3, 4, 5] # create an empty list empty = [] # create a hybrid list list2 = ['electronic', '123 ', [1, 2, 'info'], 'ss']

3: add an element to the list

1) append () adds a parameter to the end of the list.

Member = ['zookeeper ', 'zookeeper'] member. append ('ally') member ['zookeeper ', 'zookeeper', 'ally']

2) The extend () parameter is a list that extends the original list from the original list.

Member = ['zookeeper ', 'zookeeper'] member. extend ([1314, 'together ']) member ['zookeeper', 'zookeeper ', 1314, 'together']

3) insert (): the first parameter represents the location of the List, and the second parameter represents the element to be inserted.

Member = ['invalid reference', 'invalid reference'] member. insert (1, 'love') member ['invalid reference', 'love', 'invalid reference']

4) Comparison between append () and extend ()

>>> name = ['F', 'i', 's', 'h']>>> name.append('C')>>> name['F', 'i', 's', 'h', 'C']>>> name.extend(['.', 'c'])>>> name['F', 'i', 's', 'h', 'C', '.', 'c']>>> name.append(['o', 'm'])>>> name['F', 'i', 's', 'h', 'C', '.', 'c', ['o', 'm']]

Have you understood this example?

4: Method for retrieving elements from the list

Like arrays, you can use member [0] to change the index value to obtain the corresponding element.

>>> Member = ['zookeeper ', 'zookeeper'] >>> member [0] 'zookeeper '>>> member [1] 'zookeeper'

5. Method for deleting elements from the list

1) The remove () parameter is the name in the known list. You only need to know the name.

>>> List2 = ['4. adad', '3. li Ning ',' 2. kapa', '1. nike '] >>> list2.remove (' 3. li Ning ') >>> list2 [' 4. adads', '2. kapa', '1. nike ']

2) del statement

>>> List2 = ['4. adad', '3. li Ning ',' 2. kapa', '1. nike '] >>> del list2 [0] >>> list2 ['3. li Ning ',' 2. kapa', '1. nike ']

3) pop () stack, pull the last element, and return it to you.

>>> List2 = ['4. adad', '3. li Ning ',' 2. kapa', '1. nike ']> list2.pop ()' 1. nike'

# Retrieve an element from the list and insert it to the front of list2 = ['4. adad', '3. li Ning ',' 2. kapa', '1. nike '] list2.insert (0, list2.pop ()> list2 ['1. nike ', '4. adad', '3. li Ning ',' 2. kapa']

6: slice of the list to get another list

>>> List1 = [9,65, 34,13, 67,9, 45,12] >>> list1 [0: 3] [9, 65, 34] >>> list1 = [9,65, 34,13, 67,9, 45, 12] >>> list2 = list1 [:] >>> list2 [9, 65, 34, 13, 67, 9, 45, 12] # note that list2 is a new list. If list3 = list1list3 is not a new list, IT and list1 only point to the same position, for example

# There is also a hidden value step for list parts. The default step size cannot be 0. The value range is 1 >>> list1 = [9, 65, 34,13, 67,9, 45,12] >>> list1 [:: 2] [9, 34, 67, 45]

7: List Operators

1) when the comparison operator has multiple elements, it starts to compare from 0th.

list1=[1,8,3]list2=[4,5,6]>>> list1>list2False>>> list1<list2True

2) logical operators

list1=[1,8,3]list2=[4,5,6]>>> list1<list2 and list1>list2False

3) join Operators

List1 = [, 3] list2 = [, 6]> list1 + list2 [1, 8, 3, 4, 5, 6] # You can use '+' only when the two lists are of the same type. If you want to add an element, use the first three methods.

4) repeated operator '*'

list1=[1,8,3]>>> list1*2[1, 8, 3, 1, 8, 3]

5) in

>>> Member = ['1. Nike ', '4. adads', '3. Li Ning', '2. kapa'] >>> '1. Nike 'in memberTrue

>>> Member = [[1, 2, 3, ['abc'], '1. nike ', '4. adad', '3. li Ning ',' 2. kapa'] >>> 'abc' in member [0] False >>> 'abc' in member [0] [3] True

>>> Member = [[1, 2, 3, ['abc', ['a'], '1. nike ', '4. adad', '3. li Ning ',' 2. kapa']
>>> A in member [0] [3] [1]

True

If the list is in the list, you must first include a level

8: list of good friends (list type built-in functions)

1) view Method

>>> dir(list)['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']

 

2) regular friends (commonly used built-in functions)

Count () calculates the number of times the list element repeats.

>>> member=[1,1,1,1,1,1,1,2]>>> member.count(1)7

Index () returns the position in the list of elements.

>>> member=[1,2,3,9,23,34,6,6,7]>>> member.index(1)0>>> member=[1,2,3,9,23,34,6,6,7]>>> member.index(9,2,7)3

Reverse the list

>>> list1=[1,2,3,4]>>> list1.reverse()>>> list1[4, 3, 2, 1]

By default, sort () is sorted from small to large, and sorted by merge.

>>> list1=[9,65,34,13,67,9,45,12]>>> list1.sort()>>> list1[9, 9, 12, 13, 34, 45, 65, 67]

How can we sort data in ascending order?

>>> List name. sort () >>> list name. reverse () # Or >>> list name. sort (reverse = True)

Clear () clear the list

>>> list2.clear()>>> list2[]

Copy () to get a new list

>>> List1 = [1, [1, 2, ['boundary '], 3, 5, 8, 13, 18] >>> list2 = list1.copy () >>> list2 [1, [1, 2, [CAPTCHA], 3, 5, 8, 13, 18]

9: List Derivation

>>> List1 = [(x, y) for x in range (10) for y in range (10) if x % 2 = 0 if y % 2! = 0] list1 = [] for x in range (10): for y in range (10): if x % 2 = 0: if y % 2! = 0: list1.append (x, y) connected # connected game list1 = ['1. jost do it ', '2. you ',' 3. can ',' 4. change the word'] list2 = ['4. adad', '3. li Ning ',' 2. kapa', '1. nike '] >>> list3 = [name +': '+ slogan [2:] for slogan in list1 for name in list2 if slogan [0] = name [0]