列表、元组、字典、集合类型及其内置方法

列表类型内置方法：

按索引取值及赋值及切片取值

my_hobby_list = ['dancing', 'reading', 'coding', 'cooking'] print(my_hobby_list[2]) print(my_hobby_list[2:]) print(my_hobby_list[-1:1:-1]) my_hobby_list[3] = 'eating' print(my_hobby_list)

长度

my_hobby_list = ['dancing', 'reading', 'coding', 'cooking'] print(len(my_hobby_list))

成员运算

my_hobby_list = ['dancing', 'reading', 'coding', 'cooking'] print('gaming' in my_hobby_list) print('cooking' not in my_hobby_list)

追加值

my_hobby_list = ['dancing', 'reading', 'coding', 'cooking'] if True: my_hobby_list.append('drinking') print(my_hobby_list)

删除

my_hobby_list = ['dancing', 'reading', 'coding', 'cooking'] del my_hobby_list[3] print(my_hobby_list) del my_hobby_list

循环

my_hobby_list = ['dancing', 'reading', 'coding', 'cooking'] for i in my_hobby_list: print(i)

其他常用方法

my_hobby_list = ['dancing', 'reading', 'coding', 'cooking'] # insert 根据索引，插入 my_hobby_list.insert(0, 'where is me') print(my_hobby_list) # pop 删除，若无指定索引，默认删除最后一个 my_hobby_list.pop() my_hobby_list.pop(0) print(my_hobby_list) # remove 根据内容而不是索引删除 my_hobby_list.remove('dancing') print(my_hobby_list) # count 计数，返回某成员出现次数 my_hobby_list.append('apple') my_hobby_list.append('apple') print(my_hobby_list) print(my_hobby_list.count('apple')) # index 索引，返回某成员第一次出现的索引 print(my_hobby_list.index('apple')) print(my_hobby_list.index('coding')) # clear 清除列表数据 my_hobby_list.clear() print(my_hobby_list) # copy 复制列表 my_new_hobby_list = ['apple', 'banana', 'cherry', 'dog', 'english'] copy_list = my_new_hobby_list.copy() print(copy_list) print(id(copy_list)) print(id(my_new_hobby_list)) my_new_hobby_list[4] = 'Deutsch' print(copy_list) print(my_new_hobby_list) print(id(my_hobby_list)) my_hobby_list = my_new_hobby_list.copy() print(id(my_hobby_list)) # extend 把一个列表内容扩展到另一个列表的后面 my_new_hobby_list.extend(copy_list) print(my_new_hobby_list) # reverse 反转列表的内容 print(my_hobby_list) my_hobby_list.reverse() print(my_hobby_list) # sort 排序，但数据内容必须是同一种类型 print(my_new_hobby_list) my_new_hobby_list.sort(reverse=False) print(my_new_hobby_list) my_new_hobby_list.sort(reverse=True) print(my_new_hobby_list)

元组的内置方法

hobby_tuple = ('apple', 'boy', 'girl', 'working') # 索引取值 print(hobby_tuple[0]) print(hobby_tuple[-1]) # 切片（顾头不顾尾，步长） print(hobby_tuple[1:]) print(hobby_tuple[::-1]) # 长度len print(len(hobby_tuple)) # 成员运算in和not in print('apple' in hobby_tuple) print('banana' not in hobby_tuple) # 循环 for i in hobby_tuple: print(i) # count print(hobby_tuple.count('girl')) # index print(hobby_tuple.index('girl'))

字典类型的方法

优先需要掌握的方法

catching_dict = {'a': 'apple', 'b': 'butterfly', 'c': 'character', 'd': 'document', 'e': 'email', 'f': 'first'} # 按key存取值：可存可取 print(catching_dict['c']) catching_dict['c'] = 'car' print(catching_dict['c']) # 长度len print(len(catching_dict)) # 成员运算in和not in print('a' in catching_dict) print('car' in catching_dict.values()) print('d' in catching_dict.values()) # 删除del & pop 补充 get popitem del catching_dict['a'] print(catching_dict) catching_dict.pop('f') print(catching_dict) print(catching_dict.get('b')) print(catching_dict.get('a')) print(catching_dict) catching_dict.popitem() print(catching_dict) # 键keys()、值values()、键值对items() catching_dict['a'] = 'apple' catching_dict['e'] = 'english' print(catching_dict) print(catching_dict.keys()) print(catching_dict.values()) print(catching_dict.items()) # 循环 for k, v in catching_dict.items(): print(k, v)

需要掌握的其他方法

# get 通过KEY获取VALUE，如果KEY不存在，返回 None print(catching_dict.get('a')) print(catching_dict.get('b')) print(catching_dict.get('c')) print(catching_dict.get('z')) # update 把一个字典的内容添加到另一个字典中 append_dict = {'z': 'zoo'} catching_dict.update(append_dict) print(catching_dict) # fromkeys 用列表里的数据作为KEY，生成一字典 new_dict = dict.fromkeys(['apple', 'banana', 'cherry'], 'delicious') print(new_dict) # setdefault 加入一组键值对，若不存在，则添加，存在则不添加 new_dict.setdefault('apple', 'good') new_dict.setdefault('zoo', 'tiger') print(new_dict)

集合类型的内置方法

# 长度len empty_set = set() fruits_a_set = {'apple', 'banana', 'cherry', 'orange', 'lemon'} fruits_b_set = {'cherry', 'orange', 'pear', 'watermelon'} print(len(empty_set)) print(len(fruits_a_set)) print(len(fruits_b_set)) # 成员运算in和not in print('cherry' in fruits_b_set) print('apple' in fruits_b_set) print('banana' not in fruits_a_set) # |并集、union print(fruits_a_set.union(fruits_b_set)) print(fruits_a_set | fruits_b_set) # &交集、intersection print(fruits_a_set.intersection(fruits_b_set)) print(fruits_a_set & fruits_b_set) # -差集、difference print(fruits_a_set - fruits_b_set) print(fruits_b_set.difference(fruits_a_set)) # ^对称差集、symmetric_difference print(fruits_a_set.symmetric_difference(fruits_b_set)) print(fruits_b_set ^ fruits_a_set) # == print(fruits_a_set == fruits_b_set) # 父集：>、>= 、issuperset fruits_c_set = fruits_a_set - fruits_b_set print(fruits_a_set >= fruits_c_set) # 子集：<、<= 、issubset print(fruits_c_set <= fruits_a_set) # add empty_set.add('peach') print(empty_set) # remove empty_set.remove('peach') print(empty_set) # difference_update print(fruits_a_set) print(fruits_b_set) fruits_a_set.difference_update(fruits_b_set) print(fruits_a_set) # discard fruits_a_set.discard('zoo') fruits_a_set.discard('apple') print(fruits_a_set) # isdisjoint print(fruits_a_set) print(fruits_b_set) print(fruits_c_set) print(fruits_a_set.isdisjoint(fruits_b_set)) print(fruits_a_set.isdisjoint(fruits_c_set))

数据类型总结

	单值/多值	可变/不可变*	有序/无序
数字	单值	不可变	无意义
字符串	单值	不可变	有序
列表	多值	可变	有序
元组	多值	不可变	有序
字典	多值	可变	无序
集合	多值	可变	无序