Re: [R] Any container in R?

From: Duncan Murdoch <>
Date: Mon 01 Jan 2007 - 17:36:12 GMT

On 1/1/2007 11:22 AM, Feng Qiu wrote:
> Hi Duncan:
> Thanks for your hints.
> I'm trying to collect distinct elements in one column in a matrix.
> If there is a map, I can easily build up such a collection. While if using
> list, I have to check by myself if this element already exists in the
> collection every time I examine a new entry in the column.

You might want to use the unique() function, or duplicated(), rather than doing this yourself.

Duncan Murdoch

> Best,
> Feng
> ----- Original Message -----
> From: "Duncan Murdoch" <>
> To: "Feng Qiu" <>
> Cc: <>
> Sent: Monday, January 01, 2007 10:37 AM
> Subject: Re: [R] Any container in R?

>> On 1/1/2007 10:17 AM, Feng Qiu wrote:
>>> R has list and array to contain elements. But does R have more powerful 
>>> container, such as "map" as in C++ STL?  or is there such a package?
>> In what way are maps more powerful than lists?  You can use names to index 
>> lists.
>> The other container in R is the environment; they have fairly strange 
>> semantics, though.
>> Duncan Murdoch

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