How to remove last element from a List<String>

Question

I have a requirement to exclude last element from a list. For example if my list is like this:

List<String> str=new List<String>{'2023, 2024, 2025, 2026, 2027'}; 

I need a new list which will have only till 2026.

If I have a list :

List<String> = new List<String>{'2023, 2024'};

I need a new list which will have only 2023.

I created a new List<string> str1 = new List<string>();

I tried to use the traditional for loop but it seems to be not working.

for(Integer i=0; i< (str.size()-1); i++){
   str1.add(str(i));
}

Error: Method does not exist or incorrect signature: void str(Integer) from the type myApexClass

Any way to add the desired output to the new List str1, please suggest.

Answer 1

You could use .remove(index) to remove the last element from a list. The index of the last element is always size() - 1.

List<String> years = new List<String>{ '2023', '2024', '2025', '2026', '2027' };
years.remove(years.size() -1 );
System.debug(years); // Print (2023, 2024, 2025, 2026)

Please note that .remove(index) returns the elment being removed, so writing years = years.remove(years.size() -1 ); would result in the following error:

Illegal assignment from String to List

Once you call .remove(index) the size of the list changes.

The for-loop idea is fine, but you should use .get(index) or the square bracket notation to get the element of index i, that's why you got

Method does not exist or incorrect signature: void str(Integer)

List<String> years = new List<String>{ '2023', '2024', '2025', '2026', '2027' };
List<String> years2 = new List<String>();
Integer lastElementIndex = years.size() - 1;
for(Integer i=0; i<lastElementIndex; i++){
   years2.add(years.get(i)); // or years2.add(years[i]);
}
System.debug(years2);