You can set *repos* in your *.Rprofile* to restore your choice every time you start R

**Edit:** to be more precise:

Add 

    options(repos=structure(c(CRAN=&quot;YOUR FAVORITE MIRROR&quot;)))

to your *.Rprofile*

---

Alternatively, you can set the mirror site-wide in your `Rprofile.site`. The location of the file is given by `?Startup`:

&gt; The
     path of this file is taken from the value of the `R_PROFILE`
     environment variable (after tilde expansion).  If this variable is
     unset, the default is `R_HOME/etc/Rprofile.site`, which is used if
     it exists (which it does not in a &#39;factory-fresh&#39; installation).

So do `Sys.getenv(&quot;R_PROFILE&quot;)` for the first option, or `Sys.getenv(&quot;R_HOME&quot;)` or `R.home()` for the second option. On macOS, the location of the second is `/Library/Frameworks/R.framework/Resources/etc/`.

The file may not exist, or you may see the following lines commented out :


    # set a CRAN mirror
    # local({r &lt;- getOption(&quot;repos&quot;)
    #       r[&quot;CRAN&quot;] &lt;- &quot;http://my.local.cran&quot;
    #       options(repos=r)})

So remove the comment marks and change &quot;http://my.local.cran&quot; to the correct website, e.g.:

```r
local({r &lt;- getOption(&quot;repos&quot;)
       r[&quot;CRAN&quot;] &lt;- &quot;http://cran.r-project.org&quot;
       options(repos=r)})
```


As far as I know, `private` is the default *everywhere* in C# (meaning that if I don&#39;t write `public`, `protected`, `internal`, etc. it will be `private` by default). (Please correct me if I am wrong.)

So, what&#39;s the reason to write that keyword, or why does it even exist for members?

For example, when an event handler is auto-generated it looks like this:

    private void RatTrap_MouseEnter(object sender, CheeseEventArgs e)
    {
        
    }

But why does it even write private if that&#39;s implied and default? Just so that novice developers (who don&#39;t know it&#39;s the C# default) know that it&#39;s private? Or is there a difference for the compiler?

Moreover, is there a case where writing &quot;private&quot; (alone) *will* change the accessibility of the member?


Any reason to write the &quot;private&quot; keyword in C#?

Here&#39;s  my code:

    include &#39;conn.php&#39;;
    $conn = new Connection();
    $query = &#39;SELECT EmailVerified, Blocked FROM users WHERE Email = ? AND SLA = ? AND `Password` = ?&#39;;
    $stmt = $conn-&gt;mysqli-&gt;prepare($query);
    $stmt-&gt;bind_param(&#39;sss&#39;, $_POST[&#39;EmailID&#39;], $_POST[&#39;SLA&#39;], $_POST[&#39;Password&#39;]);
    $stmt-&gt;execute();
    $result = $stmt-&gt;get_result();

I get the error on last line as: **Call to undefined method mysqli_stmt::get_result()**

Here is the code for conn.php:

    define(&#39;SERVER&#39;, &#39;localhost&#39;);
    define(&#39;USER&#39;, &#39;root&#39;);
    define(&#39;PASS&#39;, &#39;xxxx&#39;);
    define(&#39;DB&#39;, &#39;xxxx&#39;);
    class Connection{
        /**
         * @var Resource 
         */
        var $mysqli = null;
    
        function __construct(){
            try{
                if(!$this-&gt;mysqli){
                    $this-&gt;mysqli = new MySQLi(SERVER, USER, PASS, DB);
                    if(!$this-&gt;mysqli)
                        throw new Exception(&#39;Could not create connection using MySQLi&#39;, &#39;NO_CONNECTION&#39;);
                }
            }
            catch(Exception $ex){
                echo &quot;ERROR: &quot;.$e-&gt;getMessage();
            }
        }
    }

If I write this line: 

    if(!stmt) echo &#39;Statement prepared&#39;; else echo &#39;Statement NOT prepared&#39;;

It prints **&#39;Statement NOT prepared&#39;**. If I run the query directly in the IDE replacing ? marks with values, it works fine. Please note that $conn object works fine in other queries in the project.

Any help please.......

Call to undefined method mysqli_stmt::get_result

How can I set a specific CRAN mirror permanently in R?

I want to set it permanently in my laptop so that when I do `install.packages()`, it won&#39;t ask me again which mirror to choose.

Set default CRAN mirror permanent in R

<p>How can I set a specific CRAN mirror permanently in R?</p>
<p>I want to set it permanently in my laptop so that when I do <code>install.packages()</code>, it won't ask me again which mirror to choose.</p>


`.SD` looks useful but I do not really know what I am doing with it. What does it stand for? Why is there a preceding period (full stop). What is happening when I use it?

I read: 
*`.SD` is a `data.table` containing the subset of `x`&#39;s data for each group, excluding the group column(s). It can be used when grouping by `i`, when grouping by `by`, keyed `by`, and _ad hoc_ `by`*

Does that mean that the daughter `data.table`s is held in memory for the next operation?

What does .SD stand for in data.table in R

Is there a way of creating scatterplots with marginal histograms just like in the sample below in `ggplot2`? In Matlab it is the `scatterhist()` function and there exist equivalents for R as well. However, I haven&#39;t seen it for ggplot2.

![scatterplot with marginal histograms][1]

I started an attempt by creating the single graphs but don&#39;t know how to arrange them properly.

     require(ggplot2)
     x&lt;-rnorm(300)
     y&lt;-rt(300,df=2)
     xy&lt;-data.frame(x,y)
         xhist &lt;- qplot(x, geom=&quot;histogram&quot;) + scale_x_continuous(limits=c(min(x),max(x))) + opts(axis.text.x = theme_blank(), axis.title.x=theme_blank(), axis.ticks = theme_blank(), aspect.ratio = 5/16, axis.text.y = theme_blank(), axis.title.y=theme_blank(), background.colour=&quot;white&quot;)
         yhist &lt;- qplot(y, geom=&quot;histogram&quot;) + coord_flip() + opts(background.fill = &quot;white&quot;, background.color =&quot;black&quot;)

         yhist &lt;- yhist + scale_x_continuous(limits=c(min(x),max(x))) + opts(axis.text.x = theme_blank(), axis.title.x=theme_blank(), axis.ticks = theme_blank(), aspect.ratio = 16/5, axis.text.y = theme_blank(), axis.title.y=theme_blank() )


         scatter &lt;- qplot(x,y, data=xy)  + scale_x_continuous(limits=c(min(x),max(x))) + scale_y_continuous(limits=c(min(y),max(y)))
    none &lt;- qplot(x,y, data=xy) + geom_blank()


and arranging them with the function posted [here][2]. But to make  long story short: Is there a way of creating these graphs?


  [1]: http://i.stack.imgur.com/uKiQS.jpg
  [2]: http://gettinggeneticsdone.blogspot.com/2010/03/arrange-multiple-ggplot2-plots-in-same.html

Scatterplot with marginal histograms in ggplot2

What are the main differences between vector and list data types in R? What are the advantages or disadvantages of using (or not) these two data types?

I would appreciate seeing examples that demonstrate the use cases of the data types.

What are the differences between vector and list data types in R?

I have a character string and what to extract the information inside of multiple parentheses.  Currently I can extract the information from the last parenthesis with the code below.  How would I do it so it extracts multiple parentheses and returns as a vector? 

    j &lt;- &quot;What kind of cheese isn&#39;t your cheese? (wonder) Nacho cheese! (groan) (Laugh)&quot;                                                          
    sub(&quot;\\).*&quot;, &quot;&quot;, sub(&quot;.*\\(&quot;, &quot;&quot;, j)) 

Current output is:

    [1] &quot;Laugh&quot;

Desired output is:

    [1] &quot;wonder&quot; &quot;groan&quot;  &quot;Laugh&quot; 

Extract info inside all parenthesis in R

The &quot;[Writing R Extensions][1]&quot; manual provides the following guidance on when to use Imports or Depends:

&gt; The general rules are
&gt;     
&gt; - Packages whose namespace only is needed to load the package using library(pkgname) must be listed in the ‘Imports’ field and not in the
&gt; ‘Depends’ field.
&gt; - Packages that need to be attached to successfully load the package using library(pkgname) must be listed in the ‘Depends’ field, only.

Can someone provide a bit more clarity on this?  How do I know when my package only needs namespaces loaded versus when I need a package to be attached?  What are examples of both?  I think the typical package is just a collection of functions that sometimes call functions in other packages (where some bit of work has already been coded-up).  Is this scenario 1 or 2 above?

**Edit**

I wrote a [blog post] with a section on this specific topic (search for &#39;Imports v Depends&#39;).  The visuals make it a lot easier to understand.

  [1]: http://cran.r-project.org/doc/manuals/R-exts.html#The-DESCRIPTION-file
[blog post]: http://blog.obeautifulcode.com/R/How-R-Searches-And-Finds-Stuff/ 

Better explanation of when to use Imports/Depends

Suppose I need to install a number of packages on a (Linux) machine that does not have an internet connection. Let&#39;s say that I downloaded a copy of cran and burned it on a DVD that I bring to the offline location:

    wget ftp://cran.r-project.org/pub/R/src/contrib/*.tar.gz

I can even add a PACKAGES file that contains an overview of all the source packages and their dependencies:

    library(tools)
    write_PACKAGES()

How could I use this offline to install a source package in such a way that dependencies are resolved and installed from the local files as well? For example, someone wants to install package ggplot2, which has a fairly deep dependency structure. Assume the source package of ggplot2 and all of its dependencies are available as source packages in the current working directory. If I do:

    install.packages(&quot;ggplot2_0.9.1.tar.gz&quot;, repos=NULL)

This results in an error, because the dependencies are not resolved at all. Alternatively: 

    install.packages(list.files(pattern=&quot;*.tar.gz&quot;), repos=NULL)

However this also ignores the dependency structure, and tries to install packages in alphabetical order, which will also fail. 

I looked into `available.packages` and `contrib.url` but I just can&#39;t find an example of installing a source package from a local file including it&#39;s dependencies.



Offline install of R package and dependencies

I&#39;m trying to install a package through the R prompt by doing the following:

    install.packages(&#39;RMySQL&#39;)

But the output is as follows: 

    --- Please select a CRAN mirror for use in this session ---

And nothing else! I can&#39;t find a solution to this very basic problem. What am I supposed to type in order to select a CRAN mirror? 

EDIT: 

OS: Mac-OS X 10.6.8
R Version: 2.15.0

How to select a CRAN mirror in R

I develop a package in R and when I check and build it in my local computer it works properly. But when I tried it in CRAN, I get a package dependencies error. My package depends on two functions of other packages.  

If I list the other packages under the `description` using `Depends` or `imports`, will it be automatically installed with the new package? Or do I need to explicitly invoke the function `install.packages(&quot;packagename&quot;)` under the function that I&#39;ve used the other packages. if this all is wrong, what is the best way to solve package dependencies in `R` inorder to pass the `R CMD check` and `build` test and submit to CRAN?

Thank you.


How to tell CRAN to install package dependencies automatically?

When I run `R CMD check --as-cran`  on my package, the one note I still get is:

    checking CRAN incoming feasibility ... NOTE 
    Maintainer:[my name] &lt;my email&gt;

I can&#39;t seem to find a good explanation of this note, although I haven&#39;t read anything that tells my I should be concerned about it.  As anyone else run into this?  Is there anything I can do that will clear the note?

checking CRAN incoming feasibility ... NOTE Maintainer

I have built an R package, i.e. I have the mypackage.tar.gz file. This package depends on several other packages, all downloadable and installable from any CRAN mirror.

Now I want to install this package on a system where the dependencies are not yet installed, and I would like that the dependencies will be downloaded and installed automatically when I install my package.

I tried:

    install.packages(&quot;mypackage.tar.gz&quot;,type=&quot;source&quot;,dependencies=TRUE,repos=&quot;http://a.cran.mirror&quot;)

but it searches for `mypackage.tar.gz` on the mirror (and obviously it does not find), while if I set `repos=NULL` it correctly tries to install the local package file (as documented), but obviously it does not find the dependencies packages.

**So my question is: is there a way to perform a &#39;mixed&#39; installation (local package with online dependencies) or the only way to do is to manually install all the dependencies?**




Install a local R package with dependencies from CRAN mirror

I have a data set of stock prices that have already been rounded to 2 decimal places `(1234.56)`.  I am now trying to round to a specific value which is different for each stock.  Here are some examples:

    Current Stock Price         Minimum Tick Increment       Desired Output
      123.45                            .50                      123.50
      155.03                            .10                      155.00
      138.24                            .50                      138.00
      129.94                            .10                      129.90
       ...                              ...                       ...

I&#39;m not really sure how to do this but am open to suggestions.

R round to nearest .5 or .1

I am trying to load a csv file that has 14 columns like this:

    StartDate, var1, var2, var3, ..., var14

when I issue this command:

    systems &lt;- read.table(&quot;http://getfile.pl?test.csv&quot;, header = TRUE, sep = &quot;,&quot;)

I get an error message.
&gt; duplicate row.names are not allowed

It seems to me that the first column name is causing the issue. When I manually download the file and remove the `StartDate` name from the file, R successfully reads the file and replaces the first column name with `X`. Can someone tell me what is going on? The file is a (comma separated) csv file.

duplicate &#39;row.names&#39; are not allowed error

Let&#39;s say that I have a date in R and it&#39;s formatted as follows.

       date      
    2012-02-01 
    2012-02-01
    2012-02-02

Is there any way in R to add another column with the day of the week associated with the date? The dataset is really large, so it would not make sense to go through manually and make the changes.

    df = data.frame(date=c(&quot;2012-02-01&quot;, &quot;2012-02-01&quot;, &quot;2012-02-02&quot;)) 

So after adding the days, it would end up looking like:

       date       day
    2012-02-01   Wednesday
    2012-02-01   Wednesday
    2012-02-02   Thursday

Is this possible? Can anyone point me to a package that will allow me to do this?
Just trying to automatically generate the day by the date.


Find the day of a week

I would like to change the format (class) of some columns of my data.frame object (`mydf`) from *charactor* to *factor*.

I don&#39;t want to do this when I&#39;m reading the text file by `read.table()` function.

Any help would be appreciated.

Convert data.frame column format from character to factor

The following code is obviously wrong.  What&#39;s the problem?

    i &lt;- 0.1
    i &lt;- i + 0.05
    i
    ## [1] 0.15
    if(i==0.15) cat(&quot;i equals 0.15&quot;) else cat(&quot;i does not equal 0.15&quot;)
    ## i does not equal 0.15

Content Type	Original Author	Original Content on Stackoverflow
Question	719016	View Question on Stackoverflow
Solution 1 - R	rinni	View Answer on Stackoverflow

Set default CRAN mirror permanent in R

R Problem Overview

R Solutions

Solution 1 - R

Call to undefined method mysqli_stmt::get_result

Any reason to write the "private" keyword in C#?

Attributions