python开发基础----基本数据类型（list类型）

列表（list）

　　列表是有序的，元素可以被修改

　　列表格式

　　　　中括号括起来 以，分割每个元素,列表中元素可以是数字、字符串、列表、布尔值、所有的数据类型都能放进去（内部放置任何东西，可以嵌套任何类型）

　　　　可以通过索引或者切片取值以及删除

　　　　支持 in 和 not in 操作 

 

 　  列表元素，可以被修改

　　可以直接通过下标索引进行修改，如：

　　　　li = [1,23,432,123,'dasd']

　　　　li[1] = 'sada' ---->把23该为'sada'

　　通过切片的方式进行修改

　　　　li[1:3] = [123,23423]  --- >  li 等于 [1,123,23423,123,'dasd']

　　

　　删除的第一种方式，通过下标索引

　　　　del li[1] --->删除li的第一个元素

　　删除的第二种方式，通过切片

　　　　del li[1:3]  ---- >  li 等于 [1,123,'dasd']

　　删除的方法有 pop()、remove()、 del 、 clear

 

　　字符串可以直接通过  list(str)  转换为列表

　　列表不能直接转换为字符串

　　　　列表即有数字又有字符串的情况

　　　　　　需要自己写for循环一个一个处理

　　　　列表如果只有字符串时

　　　　　　可以用''.join(list)进行转换

　　

list类型常用的方法：

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) -- append object to end
        (在原来值最后追加，也就是在列表最后一个元素后追加) """
        pass
     def clear(self): # real signature unknown; restored from __doc__
        """ L.clear() -> None -- remove all items from L （清空列表） """
        pass
        def copy(self): # real signature unknown; restored from __doc__
        """ L.copy() -> list -- a shallow copy of L （浅拷贝）"""
        return []
    def count(self, value): # real signature unknown; restored from __doc__
        """ L.count(value) -> integer -- return number of occurrences of value （计算元素出现的次数）"""
        return 0

    def extend(self, iterable): # real signature unknown; restored from __doc__
        """ L.extend(iterable) -- extend list by appending elements from the iterable 扩展原列表（把可迭代对象【可以用for循环的对象，如string，list等】里的各元素追加到列表最后）"""
        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.
        根据值获取当前值索引，从左往右找，找到之后就不再继续往后找
        """
        return 0

    def insert(self, index, p_object): # real signature unknown; restored from __doc__
        """ L.insert(index, object) -- insert object before index 
             在指定索引位置往列表中插入元素
        """
        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.
        默认删除最后一个元素，返回该元素的值。如果提供了index参数，那就删除位于index索引的元素，返回该元素的值
        """
        pass

    def remove(self, value): # real signature unknown; restored from __doc__
        """
        L.remove(value) -- remove first occurrence of value.
        Raises ValueError if the value is not present.
        删除列表中的指定值，从左往右，删除一个元素后不再继续往后找
        """
        pass

    def reverse(self): # real signature unknown; restored from __doc__
        """ L.reverse() -- reverse *IN PLACE*
         将当前列表进行反转
         """
        pass

    def sort(self, cmp=None, key=None, reverse=False): # real signature unknown; restored from __doc__
        """
        L.sort(cmp=None, key=None, reverse=False) -- stable sort *IN PLACE*;
        cmp(x, y) -> -1, 0, 1
        排序，默认从小到大排序，reverse=True，代表从大到小排序
        """
        pass

    def __add__(self, y): # real signature unknown; restored from __doc__
        """ x.__add__(y) <==> x+y """
        pass

    def __contains__(self, y): # real signature unknown; restored from __doc__
        """ x.__contains__(y) <==> y in x """
        pass

    def __delitem__(self, y): # real signature unknown; restored from __doc__
        """ x.__delitem__(y) <==> del x[y] """
        pass

    def __delslice__(self, i, j): # real signature unknown; restored from __doc__
        """
        x.__delslice__(i, j) <==> del x[i:j]
                   
                   Use of negative indices is not supported.
        """
        pass

    def __eq__(self, y): # real signature unknown; restored from __doc__
        """ x.__eq__(y) <==> x==y """
        pass

    def __getattribute__(self, name): # real signature unknown; restored from __doc__
        """ x.__getattribute__('name') <==> x.name """
        pass

    def __getitem__(self, y): # real signature unknown; restored from __doc__
        """ x.__getitem__(y) <==> x[y] """
        pass

    def __getslice__(self, i, j): # real signature unknown; restored from __doc__
        """
        x.__getslice__(i, j) <==> x[i:j]
                   
                   Use of negative indices is not supported.
        """
        pass

    def __ge__(self, y): # real signature unknown; restored from __doc__
        """ x.__ge__(y) <==> x>=y """
        pass

    def __gt__(self, y): # real signature unknown; restored from __doc__
        """ x.__gt__(y) <==> x>y """
        pass

    def __iadd__(self, y): # real signature unknown; restored from __doc__
        """ x.__iadd__(y) <==> x+=y """
        pass

    def __imul__(self, y): # real signature unknown; restored from __doc__
        """ x.__imul__(y) <==> x*=y """
        pass

    def __init__(self, seq=()): # known special case of list.__init__
        """
        list() -> new empty list
        list(iterable) -> new list initialized from iterable's items
        # (copied from class doc)
        """
        pass

    def __iter__(self): # real signature unknown; restored from __doc__
        """ x.__iter__() <==> iter(x) """
        pass

    def __len__(self): # real signature unknown; restored from __doc__
        """ x.__len__() <==> len(x) """
        pass

    def __le__(self, y): # real signature unknown; restored from __doc__
        """ x.__le__(y) <==> x<=y """
        pass

    def __lt__(self, y): # real signature unknown; restored from __doc__
        """ x.__lt__(y) <==> x<y """
        pass

    def __mul__(self, n): # real signature unknown; restored from __doc__
        """ x.__mul__(n) <==> x*n """
        pass

    @staticmethod # known case of __new__
    def __new__(S, *more): # real signature unknown; restored from __doc__
        """ T.__new__(S, ...) -> a new object with type S, a subtype of T """
        pass

    def __ne__(self, y): # real signature unknown; restored from __doc__
        """ x.__ne__(y) <==> x!=y """
        pass

    def __repr__(self): # real signature unknown; restored from __doc__
        """ x.__repr__() <==> repr(x) """
        pass

    def __reversed__(self): # real signature unknown; restored from __doc__
        """ L.__reversed__() -- return a reverse iterator over the list """
        pass

    def __rmul__(self, n): # real signature unknown; restored from __doc__
        """ x.__rmul__(n) <==> n*x """
        pass

    def __setitem__(self, i, y): # real signature unknown; restored from __doc__
        """ x.__setitem__(i, y) <==> x[i]=y """
        pass

    def __setslice__(self, i, j, y): # real signature unknown; restored from __doc__
        """
        x.__setslice__(i, j, y) <==> x[i:j]=y
                   
                   Use  of negative indices is not supported.
        """
        pass

    def __sizeof__(self): # real signature unknown; restored from __doc__
        """ L.__sizeof__() -- size of L in memory, in bytes """
        pass

    __hash__ = None

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