Lists

Lists are pretty self explanatory, they work exactly how you'd expect them to.

Functionality
​Nevertheless, they're an incredibly useful resource in programming, so this article will cover how they work.

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Starting point
One thing you must remember about lists, is that they start at position zero. So if a list has four entries, the final entry will be position 3. This can be confusing at first.

GML
Player_List = ds_list_create();

Python
Player_List = list()
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Just call the list creation function, and a list will magically be created! ​

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​GML
ds_list_add( Player_List, "Jake" );

Python
Player_List.append( "Jake" );
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​Super easy stuff, right? :D

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GML
ds_list_add( Player_List, "Bob", "Dave" );

Python
Player_List.extend( [ "Bob", "Dave" ] )
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To save space and processing time, you can add multiple entries to a list in one swoop.

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GML
Name = ds_list_find_value( Player_List, 1 );

Python
Name = Player_List[ 1 ]
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In this case, you'd get "Bob", as that's what's at position 1.
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Requesting a position outside the list will return undefined in GML, and will give an error in python.

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GML
Pos = ds_list_find_index( Player_List, "Dave" );

Python
Pos = Player_List.index( "Dave" )

You can find the position of an entry in a list. Here, position 2 will be returned, as that's where Dave is at.

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Be careful here!

​In GML, if you search for an entry that's not in the list, you'll be returned with position -1, which is fine.

But in python, you'll get an error message!

​You can either use a try statement, or you can use the next function I'm about to explain!
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This function is exclusive to Python, but if you need it in GML don't worry, I've got you covered :D
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GML (My script linked above)
​Total = ds_list_count( Player_List, "Sam" );

Python
​Total = Player_List.count( "Sam" )
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Here, Total =  zero, because "Sam" isn't in the list. If an entry occurs zero times in a list, you know not to search for them!

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GML
​ds_list_delete( Player_List, 1 );

Python
del( Player_List[ 1 ] )
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Simply enter the position on the list to delete. ​If you don't know the position, you can find it with the search code above! 

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GML
ds_list_insert( Player_List, 1, "Bob" );
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Python
Player_List.insert( 1, "Bob" )
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Bob is back! It's almost like he never was deleted.

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GML
Size = ​ds_list_size( Player_List );

Python
Size = len( Player_List )
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GML
​ds_list_shuffle( Player_List );

Python
Player_List.shuffle()
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Remember, this doesn't guarantee every entry will be in a new position! There's a chance that a new random position will be the same position as before.

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GML
ds_list_clear( Player_List );

Python
Player_List.clear()

This deletes all the entries in the list, but doesn't actually delete the list itself. 

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GML
ds_list_destroy( Player_List );

Python
del( Player_List )
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The only difference between the two, is that you're deleting the variable in python. You can't delete variables in GML.

​Instead, you're deleting the structure itself.

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Thank you for reading, I hope you enjoyed this article!