We can get the index of the first element in our list using the index() function.first_index = my_list.index('a') print(first_index) # 0As you can see, my_list.index('a') returns the index of the first element ‘a’ in my_list, which is 0....
Thepop()method is another way to remove an element from a list in Python. By default,pop()removes and returns the last element from the list. However, we can also specify the index of the element to be removed. So, here we will use the index number of the first element to remove i...
list_1 = list_2 = list_3 = list_4 = ['I','am','very','happy'] dellist_1[0]# list_1 == ['am', 'very', 'happy'] list_2.remove('I')# list_2 == ['am', 'very', 'happy'] list_3.pop()# list_3 == ['I'...
first_element = my_list[0] # 结果: 1 last_element = my_list[-1] # 结果: 4 修改列表元素 通过索引直接赋值来修改元素。 my_list[1] = 10 # my_list 变为 [1, 10, 3, 4] 添加元素append extend insert append(x): 在列表末尾添加一个元素 x。 extend(iterable): 将一个可迭代对象的元素...
So I’m going to construct a list of numbers. 我要称之为数字。 I’m going to call it numbers. 我将使用数字2、4、6和8。 And I’ll use numbers 2, 4, 6, and 8. 假设我想提取或访问列表中的第一个元素。 Imagine I wanted to extract, or access, the first element of my list. 我要...
alist[-1:] # will return an empty list astr = '' astr[-1] # will generate an IndexError exception whereas astr[-1:] # will return an empty str 1. 2. 3. 4. 5. 6. 区别在于返回空列表对象或空str对象更像是“异常元素”,而不是异常对象。
定义:列表就是用中括号包围、逗号隔开的任何东西(称作元素element),没有数量,长度限制。用中括号[]加序号访问列表元素的方法就是索引index,索引就是列表元素所在的位置,索引从0 而不是1 开始,第二个元素索引为1,第三个索引为2,依次类推。 列表元素访问 ...
老Python带你从浅入深探究List 列表 Python中的列表(list)是最常用的数据类型之一。 Python中的列表可以存储任意类型的数据,这与其他语言中的数组(array)不同。 被存入列表中的内容可称之为元素(element)或者数据项(data item)亦或是值(value)。 虽然Python列表支持存储任意类型的数据项,但不建议这么做,事实上...
Write a Python program to find the index of the first element in the given list that satisfies the provided testing function. Use a list comprehension, enumerate() and next() to return the index of the first element in nums for which fn returns True. ...
of the first element greater than 'n' in the list.n=73print("\nIndex of the first element which is greater than",n,"in the said list:")print(first_index(nums,n))# Set the value 'n' to 21 and print a message indicating the index of the first element greater than 'n' in the...