In this paper, the list, dictionary, tuple and collection data structure of Python are summarized in detail. Share to everyone for your reference. The specific analysis is as follows:
List:
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Shoplist = [' Apple ', ' mango ', ' carrot ', ' banana ']
Dictionary:
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Di = {' A ': 123, ' B ': ' Something '}
Collection:
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Jihe = {' Apple ', ' pear ', ' apple '}
META Group:
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1. List
Empty list: a=[]
Function method:
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A.append (3) >>>[3]
A.extend ([3,4,5]) >>>[3,3,4,5] #添加一个列表序列
A.insert (1, ' hello ') >>>[3, ' Hello ', 3,4,5]
A.remove (3) >>>[' Hello ', 3,4,5] #删除第一个出现的3, no 3 error
A.pop () >>>[' hello ', 3,4]
A.pop (0) >>>[3,4]
A.index (4) >>>1 #返回出现的第一个4的下标
A.count (3) >>>1 #列表中元素3的个数
A.sort >>>[3,4] #排序
A.reverse () >>>[4,3] #反序
Ways to delete an element:
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A.remove (3) #通过值删除元素, delete the first parameter worthy element
A.pop () #通过下标删除元素, deletes the last value of the list by default, and deletes the element with the parameter value labeled as a parameter
Del A[0] #通过下标删除元素,
Del A[2:4] #删除a表下标为2, element of 3
Del a[:] #删除a列表所有元素
Del a #删除列表
List derivation:
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VEC = [2,4,6]
[3*x for X in VEC if X<6] >>>[6,12] 3*2,3*4
VEC2 = [1,2,3]
[X*y for x in Vec for y in VEC2] >>>[2,4,6,4,8,12,6,12,18]
Nested list derivation:
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Mat = [
[1,2,3],
[4,5,6],
[7,8,9]
]
print ([[[Row[i] for row in mat] for i in [0,1,2]])
>>>[[1, 4, 7], [2, 5, 8], [3, 6, 9]]
Think: What will be the difference between list (Zip (MAT)) and list (Zip (*mat))
2. META Group
null tuple: t = ()
Tuple Assignment: T = (123,345)
T[0] >>>123
3. Dictionary
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D = {' Jack ': ' jack@mail.com ', ' Tom ': ' Tom@main.com '}
d[' Jack '] >>> ' jack@mail.com
d[' jim ' = ' Jim@sin.com ' >>>{' jim ': ' Jim@sin.com ', ' Jack ': ' jack@mail.com ', ' Tom ': ' Tom@main.com '}
Del d[' Jim '] >>>{' Jack ': ' jack@mail.com ', ' Tom ': ' Tom@main.com '}
List (D.keys ()) #将返回一个字典中所有关键字组成的无序列表
Sorted (D.keys ()) #将返回一个字典中所有关键字组成的排序列表
Dict () #构造函数可以直接从key Create a dictionary in-value pairs
Dict ([(' Tim ', 123), (' Tiny ', 234)]) >>>{' Tiny ': 234, ' Tim ': 123}
To create a dictionary in a derived style:
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{d2:d2+ ' @main. com ' for D2 in List (D.keys ())}
>>>{' Jack ': ' Jack@main.com ', ' Tom ': ' Tom@main.com '}
Exercise: Loop output Dictionary key value pairs:
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For Name,email in D.items ():
Print (Name,email)
4. Collection
Empty collection: A = set () ※ to create an empty collection, you must use Set ()
Demonstrate:
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Basket = {' Apple ', ' orange ', ' apple '} >>>{' orange ', ' Apple '} #注意重复的元素只显示一个
' Apple ' in basket >>>true
' Pear ' in basket >>>false
Mathematical operation of a set:
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A = set (' ABABCDABCA ') >>>{' C ', ' B ', ' A ', ' d '}
b = {' A ', ' B ', ' m '} >>>{' B ', ' A ', ' m '}
A-b >>>{' C ', ' d '}
B-a >>>{' m '}
A | b >>>{' C ', ' d ', ' B ', ' A ', ' m '}
A & B >>>{' A ', ' B '}
A ^ b >>>{' C ', ' d ', ' m '}
Set Derivation:
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{x for x on a if x not in ' AB '} >>>{' C ', ' d '}
I hope this article will help you with your Python programming.
