extracting elements from a list of lists

• To: mathgroup at smc.vnet.net
• Subject: [mg5811] extracting elements from a list of lists
• From: Olivier Georg <olivier.georg at studi.epfl.ch>
• Date: Wed, 22 Jan 1997 00:44:15 -0500
• Organization: EPF Lausanne
• Sender: owner-wri-mathgroup at wolfram.com

```Hi,

Suppose I have lists within a list, like:

myList = {{a,b}, {c,d}}

and I want to extract some element (let's say the d).
I can request:

myList[[2,2]].

Now suppose what I have the index of the element as
the list {2,2}.  Then I can do:

Fold[Part, myList, {2,2}]

Is it correct to suppose that it will first return the
2nd sublist, and then extract the second element from it?
How efficient is it?  This may be a crucial point
if I have long lists, I think.  Then isn't there a
better way of doing this?

Olivier
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```

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