How to set a cycle so that an IndexError error is not produced

Question

The check function has two parameters: param - the number of elements in the list and num - the list itself. First, we check whether the number of specified elements in the list matches the number that was entered by the user. Next, I have the following task: I have to see if there are identical elements in the list and delete one of them. I get the error IndexError: list index out of range in line 13. Help please, it is very necessary. Thank!

def check(param, num): if (param != len(num)): print(param) print(len(num)) return False else: a = len(num) for i in range(a): for j in range(a): if (i == j): continue else: if (num[i] == num[j]): num.pop(j) return num c = 9 d = [2, 1, 3, 2, 9, 1, 2, 3, 1] print(check(c, d))

It should return a list in which there are no identical elements if the previous condition is met.
If the number of items in the list corresponds to the stated?
This is followed by the next branch of the function in which the deletion of identical elements in the list is assumed.

Accepted Answer · 2018-10-21T11:19:05

Error in this block:

 a = len(num) for i in range(a): for j in range(a): if (i == j): continue else: if (num[i] == num[j]): num.pop(j)

The fact is that after num.pop(j) , which removes elements from the list, the number of elements in the list decreases and the variable a does not change, so there will come a moment when the value of j or i in the cycle exceeds the number of elements present in the list .

As it seems to me, the solution might look like this:

 def check(param, num): if len(num) == param: return list(sorted(set(num), key=lambda s: num.index(s))) else: print('Заявленное количество элементов %s\n' 'не соответвует реальному %s' % (param, len(num))) return False

Solution via loop (with output formatting did not bother):

 def check(param: int, num: list): if param == len(num): for _ in range(len(num)): for j in range(len(num)): if num.count(num[j]) > 1: num.pop(j) break print(num) return True else: return False

Yes, I realized that there was an error in this block, I even indicated a line.

How to set a cycle so that an IndexError error is not produced

1 answer 1

Error in this block:

As it seems to me, the solution might look like this:

Solution via loop (with output formatting did not bother):

More articles: