为了防止IndexError: list index out of range,请使用以下语法: mylist = [1, 2, 3, 4] # With None as default value: value = mylist and mylist[-1] # With specified default value (option 1): value = mylist and mylist[-1] or 'default' # With specified default value (option 2): ...
如果列表中 没有找到 要查询的数据元素 , 报 ValueError 错误 ; List#index 函数原型 : def index(self, *args, **kwargs): # real signature unknown """ Return first index of value. 返回值的第一个索引。 Raises ValueError if the value is not present. 如果值不存在则引发ValueError。 """ pass...
L.pop([index]) -> item -- remove and return item at index (default last). Raises IndexError if list is empty or index is out of range. """ pass (7)def remove(self, value): 移除列表中的指定值第一个 # real signature unknown; restored from __doc__ """ L.remove(value) -- re...
4、L.index(value, [start, [stop]]) -> integer -- return first index of value 从列表中找出某个值第一个匹配项的索引位置,如果没有找到对象则抛出异常 >>> list3 = ['zhangsan','lishi','laowang'] >>> list3.index('lishi') 1 >>> list3.index('lishi',2,3) Traceback (most recent c...
| list(iterable) -> new list initialized from iterable's items | | Methods defined here:各种方法的使用 | 1.__add__(...)列表相加,相当于连接 | x.__add__(y) <==> x+y | 例:方法1: 方法2:(两种方法结果一样,对于后面的介绍,只对一种举例介绍 ...
>>> initial_value=0 >>> list_length=5 >>> sample_list=[initial_value]*list_length >>> print sample_list [0, 0, 0, 0, 0] >>> sample_list=[initial_value for i in range(10)] >>> print sample_list [0, 0, 0, 0, 0, 0, 0, 0, 0, 0] ...
调用tuple#index 函数 , 可以查找 元组 中指定元素 对应的下标索引 ; 函数原型如下 : 代码语言:javascript 代码运行次数:0 运行 AI代码解释 defindex(self,*args,**kwargs):# real signature unknown""" Return first indexofvalue.Raises ValueErrorifthe value is not present.""" ...
iterator = iter(iterable) value = next(iterator) iter()函数接收一个可迭代对象作为参数,返回的是可迭代对象的迭代器。 next()函数接收迭代器对象为参数,返回从迭代器获取的值,并将迭代器往下推进一位。next()函数的迭代器参数可以是iter()函数的返回值,也可以是其他途径获得的迭代器。例如: my_list = [...
Return Value from List index() The index() method returns the index of the given element in the list. If the element is not found, a ValueError exception is raised. Note: The index() method only returns the first occurrence of the matching element. Example 1: Find the index of the ele...
If the value is not found in the sequence, the function raises a ValueError. For example, if we have a list[1, 2, 3, 4, 5], we can find the index of the value3by callinglist.index(3), which will return the value2(since3is the third element in the list, and indexing starts ...