list文档
文档
class list(object): """ list() -> new empty list list(iterable) -> new list initialized from iterable's items """ def append(self, p_object): # real signature unknown; restored from __doc__ """ L.append(object) -> None -- append object to end 在列表的最后添加元素 """ pass def clear(self): # real signature unknown; restored from __doc__ """ L.clear() -> None -- remove all items from L 清楚列表所有元素 """ pass def copy(self): # real signature unknown; restored from __doc__ """ L.copy() -> list -- a shallow copy of L 复制一个列表 需要注意的是这个拷贝是‘浅拷贝’: 如果列表只有一层(如:l=[1,2,3]),那么l的copy后列表跟l的内存地址是不同的,但是, 但是,如果l里面嵌套的还有列表(如:l = [1,2,3,[5,6]]),那么,虽然外层列表地址不同 但是嵌套的[5,6]这个列表(也就是l[3])的内存地址跟copy后的内存地址不同 ---------------------------------------------------------------------------- l1 = [1,2,[3,4]] l2 = l1.copy() print(l1 == l2) # True print(l1 is l2) # False print(l1[2] is l2[2]) # True l1[2].append('8') # 往子列表l[2]里添加元素,l2也会随之改变 print(l2) # [1, 2, [3, 4, '8']] ---------------------------------------------------------------------------- 如果要深拷贝,则需要导入deepcopy模块 import copy l1 = [1,2,[3,4]] l2 = copy.deepcopy(l1) print(l1 == l2) # True print(l2 is l1) # False l1[2].append('8') #往子列表l[2]里添加元素,l2不会随之改变 print(l1) # [1, 2, [3, 4, '8']] print(l2) # [1, 2, [3, 4]] """ return [] def count(self, value): # real signature unknown; restored from __doc__ """ L.count(value) -> integer -- return number of occurrences of value 计算一个元素在一个列表里出现的次数 """ return 0 def extend(self, iterable): # real signature unknown; restored from __doc__ """ L.extend(iterable) -> None -- extend list by appending elements from the iterable 往列表里拓展元素,参数必须是一个可迭代对象(包括列表,元组以及字符串等……) """ pass def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__ """ L.index(value, [start, [stop]]) -> integer -- return first index of value. Raises ValueError if the value is not present. 获取列表中某一个元素的索引值,如果有重复元素,只返回第一个 也可以用可选参数start和stop来指定查找范围 """ return 0 def insert(self, index, p_object): # real signature unknown; restored from __doc__ """ L.insert(index, object) -- insert object before index 在指定位置的前一个位置插入指定元素 """ pass def pop(self, index=None): # real signature unknown; restored from __doc__ """ L.pop([index]) -> item -- remove and return item at index (default last). Raises IndexError if list is empty or index is out of range. 删除列表的元素,可以按索引来指定删除的元素,不指定的话默认删除最后一个 如果指定索引超出范围,则会报错 """ pass def remove(self, value): # real signature unknown; restored from __doc__ """ L.remove(value) -> None -- remove first occurrence of value. Raises ValueError if the value is not present. 按照元素值来删除列表的元素 如果指定元素不存在则会报错 """ pass def reverse(self): # real signature unknown; restored from __doc__ """ L.reverse() -- reverse *IN PLACE* 将一个列表反转 """ pass def sort(self, key=None, reverse=False): # real signature unknown; restored from __doc__ """ L.sort(key=None, reverse=False) -> None -- stable sort *IN PLACE* 将列表按照指定的规则排序 可以用key来指定排序规则,不指定的话默认按照asc码来排序 字符串不能跟数字类型一起排序 ---------------------------------------------------------------------- l1 = [1,2,5,3,8,6] l1.sort() print(l1) # [1, 2, 3, 5, 6, 8] l2 = ['c','b','a'] # ['a', 'b', 'c'] l2.sort() print(l2) l3 = ['fuyong','age','name'] l3.sort() print(l3) # ['age', 'fuyong', 'name'] ---------------------------------------------------------------------- key是一个可选的参数,接收一个函数名或者一个匿名函数 l4 = [(1,3),(2,1),(3,2)] l4.sort(key=lambda x:x[0]) print(l4) # [(1, 3), (2, 1), (3, 2)] l4.sort(key=lambda x:x[1]) print(l4) # [(2, 1), (3, 2), (1, 3)] ---------------------------------------------------------------------- l5 = [{'age':13},{'age':18},{'age':16}] l5.sort(key=lambda x:x['age']) print(l5) # [{'age': 13}, {'age': 16}, {'age': 18}] ---------------------------------------------------------------------- 可以用reverse参数来指定是正序还是倒叙,不指定的话默认正序 l5.sort(key=lambda x:x['age'],reverse=True print(l5) # [{'age': 18}, {'age': 16}, {'age': 13}] """ pass
示例
l1 = [1,2,[3,4]] l2 = l1.copy() print(l1 == l2) print(l1 is l2) print(l1[2] is l2[2]) l1[2].append('8') print(l2) import copy l1 = [1,2,[3,4]] l2 = copy.deepcopy(l1) print(l1 == l2) print(l2 is l1) l1[2].append('8') print(l1) print(l2) l = [1,2,3,4,5,6] l.pop() print(l) l.pop(3) print(l) l1 = [1,2,5,3,8,6] l1.sort() print(l1) l2 = ['c','b','a'] l2.sort() print(l2) l3 = ['fuyong','age','name'] l3.sort() print(l3) l4 = [(1,3),(2,1),(3,2)] l4.sort(key=lambda x:x[0]) print(l4) l4.sort(key=lambda x:x[1]) print(l4) l5 = [{'age':13},{'age':18},{'age':16}] l5.sort(key=lambda x:x['age']) print(l5) l5.sort(key=lambda x:x['age'],reverse=True) print(l5)