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    <p>It's always difficult if you are primarily familiar with only one programming language when you try to learn another that works differently, because you expect to think through a problem in a different way, and these incorrect expectations cause problems. It would be very difficult to have an introductory guide that is appropriate for students coming from each of the other languages ('you're going to think you should do X, but in R, you should do Y'). However, I can assure you that R was not designed to be ambiguous. </p> <p>Mostly, you are simply going to have to get an introductory guide and plod through it. At first, it will be a lot of work, and frustrating, but that's the only way. In the end, it will get easier. Perhaps I can tell you a couple of things to jumpstart the process: </p> <ul> <li>a <code>list</code> is just an ordered set of elements. This can be of any length, and contain any old type of thing. For example, <code>x &lt;- list(5, "word", TRUE)</code>. </li> <li>a <code>vector</code> is also an ordered set of elements. Although it can be of any length, the elements must all be of the same type. For example, <code>x &lt;- c(3,5,4)</code>, <code>x &lt;- c("letter", "word", "a phrase")</code>, <code>x &lt;- c(TRUE, FALSE, FALSE, TRUE)</code>. </li> <li>a <code>matrix</code> is a vector of vectors, where all component vectors are of the same length and type. For example, <code>x &lt;- matrix(c("a", "b", "c", "d"), ncol=2)</code>. </li> <li>a <code>data.frame</code> is a list of vectors, where all component vectors are of the same length, but do NOT have to be of the same type. For example, <code>x &lt;- data.frame(category=c("blue", "green"), amount=c(5, 30), condition.met=c(TRUE, FALSE))</code>. </li> </ul> <hr> <p><em>(response to comments:)</em> </p> <ul> <li>The function <a href="http://stat.ethz.ch/R-manual/R-patched/library/base/html/c.html" rel="nofollow noreferrer">?c</a> is for <em>concatenation</em>; <code>c(c("a", "b"), c("c", "d"))</code>, will not create a matrix, but a longer vector from two shorter vectors. The function <a href="http://stat.ethz.ch/R-manual/R-patched/library/base/html/cbind.html" rel="nofollow noreferrer">?cbind</a> (to bind columns together), or <code>rbind()</code> (to bind rows together), will create a matrix. </li> <li>I don't know of a single function that will output the type of any object. The closest thing is probably <a href="http://stat.ethz.ch/R-manual/R-patched/library/base/html/class.html" rel="nofollow noreferrer">?class</a>, but this will sometimes give, e.g., "integer", where I think you want "vector". There are also <code>mode()</code>, and <code>typeof()</code>, which are related, but aren't quite what you're looking for. Find out more about the distinctions among these <a href="https://stats.stackexchange.com/questions/3212/mode-class-and-type-of-r-objects">here</a> and <a href="https://stackoverflow.com/questions/6258004/r-types-and-classes-of-variables">here</a>. To check whether an object is a <em>specific</em> type you can use <code>is.&lt;specific type&gt;()</code>, e.g., <a href="http://rss.acs.unt.edu/Rdoc/library/base/html/vector.html" rel="nofollow noreferrer">?is.vector</a>. </li> <li>To <em>coerce</em> (i.e., 'cast') an object to a specific type, you can use <code>as.vector()</code>, but this will only work if the conditions (e.g., noted above) are met. </li> </ul>
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    1. POLearning R for someone used to MATLAB, and confusion with R data types
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    1. CO+1 As someone who knew Matlab reasonably well when I came to R (though I had used S a bit many years earlier), I'd definitely suggest getting to grips with what R lists are and how they work. In some sense they're very much the generic workhorse of R. Thinking I didn't need to worry about them much probably held up my progress with R far more than I'd care to admit. In particular, *data frames* make more sense when you realize they're lists. The other big thing is to get to grips with *writing little functions as arguments for other functions*; this is a standard paradigm in R.
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    2. COThanks. So I assume c(c("a","b"),c("c","d")) should be the same object as the matrix you defined? Also, is there a function that outputs what type an object is? By type, I mean list/vector/matrix/dataframe (not double/integer...). Another question: Is it possible to cast between these types? For example, if I define x <- list(1,2,3), can I cast it to a vector?
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