参考资料 [How to remove items from a list while iterating?]( 开始原始列表创建新列表倒序遍历列表推导式结束 通过上面的流程图,我们可以清晰地了解在Python循环中删除元素的三种方法,希望能帮助读者更好地理解和应用这些技巧。祝大家编程愉快!
Theremove()function will return a value error if an item is not in the list. Therefore, it is important to add an exception to handle such scenarios. The code below shows an example of catching the error for items not in the list. ...
importsocket#Imported sockets moduleimportsystry:#Create an AF_INET (IPv4), STREAM socket (TCP)tcp_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)exceptsocket.error, e:print'Error occurred while creating socket. Error code: '+str(e[0]) +' , Error message : '+ e[1] sys.ex...
每次while循环的时候,都会去检查list的长度(i <len(num_list)),这样,就避免了索引溢出,然后,在符合条件,删除元素[2]之后,手动把当前下标索引-1,以使下一次循环的时候,通过-1后的下标索引取出来的元素是[3],而不是略过[3]。 当然,这还不是最优解,所以,我搜索到了通用的解决方案:1、倒序循环遍历;2、遍...
list_loop_while.py #!/usr/bin/python vals = [1, 2, 3, 4, 5, 6, 7] n = len(vals) i = 0 mysum = 0 while i < n: mysum += vals[i] i += 1 print(f'The sum is {mysum}') The example calculate the sum of values in the list and prints it to the terminal. ...
foritemina[:]:ifeven(item):a.remove(item)# --> a = [1, 3] What NOT to do¶ Do not loop over the same list and modify it while iterating! This is the same code as above except that here we don't loop over a copy. Removing an item will shift all following items one place...
gender = userList[2] userList[3] = 88888 # error! access out of range, this is different with Matlab userList.append(8888) # add new elements "male" in userList # search userList[2] = 'female' # can modify the element (the memory address not change) userList.remove(8888)...
Because Python dictionaries are mutable, you can remove existing key-value pairs from them as needed. In the following example, you remove an item selectively, according to its specific value. Note that to safely shrink a dictionary while iterating through it, you need to use a copy:...
foriterating_varinsequence: statements(s) ex:使用内置enumerate函数进行遍历 forindex, iteminenumerate(sequence): process(index, item) 为什么 for-loop 可以使用未定义的变量? 循环开始时这个变量就被定义了,当然每次循环它都会被重新定义一次。 while 循环: ...
> Deleting a list item while iterating/迭代列表时删除元素list_1 = [1, 2, 3, 4] list_2 = [1, 2, 3, 4] list_3 = [1, 2, 3, 4] list_4 = [1, 2, 3, 4] for idx, item in enumerate(list_1): del item for idx, item in enumerate(list_2): list_2.remove(item) for ...