[Tutor] I want some help with arrays...
Alan Gauld
alan.gauld at btinternet.com
Fri May 18 00:48:01 CEST 2007
"Alan Gilfoy" <agilfoy at frontiernet.net> wrote
>>>> array = [["1.1", "1.2"], ["2.1", "2.2"]]
>>>> array[1[2]]
This is trying to get the second element of 1.
But one doesn't have a second element, hence the error.
Just add an extra bracket:
array[1][2]
But that won;t work either because the index starts at 0 so it needs
to be:
array[0][1]
> When I nest the slices ( array[1[2]] ) I get that error message.
Note that this is not slicing. Slicing is extracting a subsection
of an array (or list) using the end points as indices
Thus:
lst = [1,3,5,7,9]
slice = lst[2:4]
will put the 3rd and 4th elements into slice(zero indexing)
Thats quite different to indexing to select a single value.
Finally, you can use layout when defining your multi
dimensional data to make it more obvious:
table = [ [1,2,3],
[4,5,6],
[7,8,9] ]
print table[1][1] #---> 5
You will get some more on data types including arrays and other
classic data structures in my tutorial under the Raw Materials topic.
Look for the Collections heading about 40% through and it extends
to the Files heading about 80% through...
--
Alan Gauld
Author of the Learn to Program web site
http://www.freenetpages.co.uk/hp/alan.gauld
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