列表:就像动态大小的数组,在其他语言中声明(C++ 中的向量和Java的ArrayList)。列表不必总是同质的,这使其成为Python最强大的工具。
元组:元组是由逗号分隔的Python对象的集合。在某些方面,元组在索引、嵌套对象和重复方面类似于列表,但与可变列表不同,元组是不可变的。
Set: Set 是一种无序的集合数据类型,它是可迭代的、可变的并且没有重复的元素。 Python 的集合类表示集合的数学概念。
字典: 在Python是一个无序的数据值集合,用于像映射一样存储数据值,与其他只保存单个值作为元素的数据类型不同,字典保存键:值对。字典中提供了键值以使其更加优化。
List、Tuple、Set 和 Dictionary 是Python中的数据结构,用于以高效的方式存储和组织数据。
List | Tuple | Set | Dictionary |
List is a non-homogeneous data structure which stores the elements in single row and multiple rows and columns | Tuple is also a non-homogeneous data structure which stores single row and multiple rows and columns | Set data structure is also non-homogeneous data structure but stores in single row | Dictionary is also a non-homogeneous data structure which stores key value pairs |
List can be represented by [ ] |
Tuple can be represented by ( ) |
Set can be represented by { } | Dictionary can be represented by { } |
List allows duplicate elements | Tuple allows duplicate elements | Set will not allow duplicate elements | Set will not allow duplicate elements but keys are not duplicated |
List can use nested among all | Tuple can use nested among all | Set can use nested among all | Dictonary can use nested among all |
Example: [1, 2, 3, 4, 5] | Example: (1, 2, 3, 4, 5) | Example: {1, 2, 3, 4, 5} | Example: {1, 2, 3, 4, 5} |
List can be created using list() function | Tuple can be created using tuple() function. | Set can be created using set() function | Dictonary can be created using dict() function. |
List is mutable i.e we can make any changes in list. | Tuple is immutable i.e we can not make any changes in tuple | Set is mutable i.e we can make any changes in set. But elements are not duplicated. | Dictionary is mutable. But Keys are not duplicated. |
List is ordered | Tuple is ordered | Set is unordered | Dictionary is ordered |
Creating an empty list l=[] |
Creating an empty Tuple t=() |
Creating a set a=set() b=set(a) |
Creating an empty dictionary d={} |
下面是List、tuple、set、dictionary的实现程序:
Python3
# Python3 program for explaining
# use of list, tuple, set and
# dictonary
# Lists
l = []
# Adding Element into list
l.append(5)
l.append(10)
print("Adding 5 and 10 in list", l)
# Popping Elements from list
l.pop()
print("Popped one element from list", l)
print()
# Set
s = set()
# Adding element into set
s.add(5)
s.add(10)
print("Adding 5 and 10 in set", s)
# Removing element from set
s.remove(5)
print("Removing 5 from set", s)
print()
# Tuple
t = tuple(l)
# Tuples are immutable
print("Tuple", t)
print()
# Dictonary
d = {}
# Adding the key value pair
d[5] = "Five"
d[10] = "Ten"
print("Dictonary", d)
# Removing key-value pair
del d[10]
print("Dictonary", d)
输出:
Adding 5 and 10 in list [5, 10]
Popped one element from list [5]
Adding 5 and 10 in set {10, 5}
Removing 5 from set {10}
Tuple (5, )
Dictonary {10: 'Ten', 5: 'Five'}
Dictonary {5: 'Five'}
列表、集合、元组和字典的应用
列表:
- 以 JSON 格式使用
- 对数组操作有用
- 在数据库中使用
元组:
- 用于通过SQL查询一次在数据库中插入记录
例如:(1.’sravan’, 34).(2.’geek’, 35) - 在括号检查器中使用
放
- 寻找独特的元素
- 加入操作
字典
- 用于创建带有列表的数据框
- 在 JSON 中使用