`mylist[c(5,7,9)]` should do it.

You want the sublists returned as sublists of the result list; you don&#39;t use `[[]]` (or rather, the function is `[[`) for that -- as Dason mentions in comments, `[[` grabs the element.

When I rotate my screen, the WebView reloads the whole page. I can&#39;t have this since some of my content contains dynamic/random material. Currently when rotated the screen reloads the original URL from the loadUrl() method. 

Any idea what&#39;s wrong with my code? 

***MainActivity.java***


    package com.mark.myapp;
    
    import android.app.Activity;
    import android.os.Bundle;
    import android.util.Log;
    import android.view.KeyEvent;
    import android.view.Menu;
    import android.webkit.WebView;
    import android.webkit.WebViewClient;
    
    public class MainActivity extends Activity {
    
    	WebView web;
    	String webURL = &quot;http://www.google.co.uk/&quot;;
    	
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            
            if (savedInstanceState != null)
                ((WebView)findViewById(R.id.web)).restoreState(savedInstanceState);
            
            web = (WebView) findViewById(R.id.web);
            web.getSettings().setJavaScriptEnabled(true);
            web.loadUrl(webURL);
            web.setPadding(0, 0, 0, 0);
            web.getSettings().setLoadWithOverviewMode(true);
            web.getSettings().setUseWideViewPort(true);
            web.getSettings().setSupportZoom(true);
            web.getSettings().setBuiltInZoomControls(true);
            
            web.setWebViewClient(new HelloWebViewClient());
        }
    
        @Override
        public boolean onCreateOptionsMenu(Menu menu) {
            getMenuInflater().inflate(R.menu.activity_main, menu);
            return true;
        }
        
        private class HelloWebViewClient extends WebViewClient {
        	public boolean shouldOverrideUrlLoading(WebView web, String url) {
        		web.loadUrl(url);
        		return true;
        	}
        }
        
        public boolean onKeyDown(int keyCode, KeyEvent event) {
        	if ((keyCode == KeyEvent.KEYCODE_BACK) &amp;&amp; web.canGoBack()) {
        		web.goBack();
        		return true;
        	}
        	return super.onKeyDown(keyCode, event);
        }
        
    }

***AndroidManifest.xml***

    &lt;manifest xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
        package=&quot;com.mark.myapp&quot;
        android:versionCode=&quot;1&quot;
        android:versionName=&quot;1.0&quot; &gt;
    
        &lt;uses-sdk
            android:minSdkVersion=&quot;8&quot;
            android:targetSdkVersion=&quot;15&quot; /&gt;
    
        &lt;application
            android:icon=&quot;@drawable/ic_launcher&quot;
            android:label=&quot;@string/app_name&quot;
            android:theme=&quot;@style/AppTheme&quot; &gt;
            &lt;activity
                android:name=&quot;.MainActivity&quot;
               
              	android:configChanges=&quot;orientation|keyboardHidden&quot;&gt;
                &lt;intent-filter&gt;
                    &lt;action android:name=&quot;android.intent.action.MAIN&quot; /&gt;
    
                    &lt;category android:name=&quot;android.intent.category.LAUNCHER&quot; /&gt;
                &lt;/intent-filter&gt;
            &lt;/activity&gt;
        &lt;/application&gt;
    	&lt;uses-permission android:name=&quot;android.permission.INTERNET&quot;/&gt;
    &lt;/manifest&gt;

Android - Preventing WebView reload on Rotate

I need to execute **ssh** from **windows command line** by providing password in a non interactive manner. I could implement the key based authentication and able to execute the ssh commands just like 

    ssh &lt;user&gt;@&lt;host&gt; &lt;command&gt;

Is there any commands like 

    ssh &lt;user&gt;@&lt;host&gt; -P &lt;password&gt; &lt;command&gt;

[![enter image description here][1]][1]

I don&#39;t know if it is feasible. However, there can be some work around for the same. Throw me some ideas to accomplish the same. 


  [1]: http://i.stack.imgur.com/j08GP.png

Execute ssh with password authentication via windows command prompt

I have a list in R some 10,000 elements long. Say I want to select only elements, 5, 7, and 9. I&#39;m not sure how I would do that without a for loop.


I want to do something like `mylist[[c(5,7,9]]` but that doesn&#39;t work. I&#39;ve also tried the `lapply` function but haven&#39;t been able to get that working either.


Select multiple elements from a list

<p>I have a list in R some 10,000 elements long. Say I want to select only elements, 5, 7, and 9. I'm not sure how I would do that without a for loop.</p>
<p>I want to do something like <code>mylist[[c(5,7,9]]</code> but that doesn't work. I've also tried the <code>lapply</code> function but haven't been able to get that working either.</p>


Is there a Python function similar to the expand.grid() function in R ? Thanks in advance.

(EDIT) Below are the description of this R function and an example.

    Create a Data Frame from All Combinations of Factors
    
    Description:
    
         Create a data frame from all combinations of the supplied vectors
         or factors.  

    &gt; x &lt;- 1:3
    &gt; y &lt;- 1:3
    &gt; expand.grid(x,y)
      Var1 Var2
    1    1    1
    2    2    1
    3    3    1
    4    1    2
    5    2    2
    6    3    2
    7    1    3
    8    2    3
    9    3    3

(EDIT2) Below is an example with the rpy package. I would like to get the same output object but without using R :

    &gt;&gt;&gt; from rpy import *
    &gt;&gt;&gt; a = [1,2,3]
    &gt;&gt;&gt; b = [5,7,9]
    &gt;&gt;&gt; r.assign(&quot;a&quot;,a)
    [1, 2, 3]
    &gt;&gt;&gt; r.assign(&quot;b&quot;,b)
    [5, 7, 9]
    &gt;&gt;&gt; r(&quot;expand.grid(a,b)&quot;)
    {&#39;Var1&#39;: [1, 2, 3, 1, 2, 3, 1, 2, 3], &#39;Var2&#39;: [5, 5, 5, 7, 7, 7, 9, 9, 9]}

**EDIT 02/09/2012:** I&#39;m really lost with Python. Lev Levitsky&#39;s code given in his answer does not work for me:

    &gt;&gt;&gt; a = [1,2,3]
    &gt;&gt;&gt; b = [5,7,9]
    &gt;&gt;&gt; expandgrid(a, b)
    Traceback (most recent call last):
      File &quot;&lt;stdin&gt;&quot;, line 1, in &lt;module&gt;
      File &quot;&lt;stdin&gt;&quot;, line 2, in expandgrid
    NameError: global name &#39;itertools&#39; is not defined

However the itertools module seems to be installed (typing `from itertools import *` does not return any error message)

R expand.grid() function in Python

Please point out the point that I am missing:  

**openSUSE 11.3**

----------


    xx@linux-y3pi:~/Desktop/R&gt; sudo R CMD INSTALL rgdal_0.7-12.tar.gz 
    root&#39;s password:
    * installing to library ‘/usr/lib64/R/library’
    * installing *source* package ‘rgdal’ ...
    ** package ‘rgdal’ successfully unpacked and MD5 sums checked
    configure: gdal-config: gdal-config
    checking gdal-config usability... ./configure: line 1353: gdal-config: command not found
    no
    Error: gdal-config not found
    The gdal-config script distributed with GDAL could not be found.
    If you have not installed the GDAL libraries, you can
    download the source from  http://www.gdal.org/
    If you have installed the GDAL libraries, then make sure that
    gdal-config is in your path. Try typing gdal-config at a
    shell prompt and see if it runs. If not, use:
     --configure-args=&#39;--with-gdal-config=/usr/local/bin/gdal-config&#39;
    with appropriate values for your installation.
    
    ERROR: configuration failed for package ‘rgdal’
    * removing ‘/usr/lib64/R/library/rgdal’


----------

    xx@linux-y3pi:~/Desktop/R&gt; whereis gdal-config
    gdal-config: /usr/local/bin/gdal-config
    
    xx@linux-y3pi:~/Desktop/R&gt; gdal-config 
    Usage: gdal-config [OPTIONS]
    Options:
     [--prefix[=DIR]]
     [--libs]
     [--dep-libs]
     [--cflags]
     [--datadir]
     [--version]
     [--ogr-enabled]
     [--formats]
     xx@linux-y3pi:~/Desktop/R&gt;


----------


    &gt; sessionInfo()
    R version 2.15.1 (2012-06-22)
    Platform: x86_64-unknown-linux-gnu (64-bit)
    
    locale:
     [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
     [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
     [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
     [7] LC_PAPER=C                 LC_NAME=C                 
     [9] LC_ADDRESS=C               LC_TELEPHONE=C            
    [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       
    
    attached base packages:
    [1] stats     graphics  grDevices utils     datasets  methods   base     
    &gt; 


----------

    xx@linux-y3pi:~/Desktop/R&gt; gdal-config --version
    1.9.0

    xx@linux-y3pi:~/Desktop/R&gt; proj
    Rel. 4.8.0, 6 March 2012
    usage: proj [ -beEfiIlormsStTvVwW [args] ] [ +opts[=arg] ] [ files ]


----------

    linux-y3pi:~ # $PATH
    bash: /home/xx/qtsdk-2010.05/qt/bin/:/home/xx/qtsdk-2010.05/bin:/home/xx/qtsdk-2010.05/qt/bin:/home/xx/qtsdk-2010.05/qt/bin/:/home/xx/qtsdk-2010.05/bin:/usr/lib64/mpi/gcc/openmpi/bin:/home/xx/bin:/usr/local/bin:/usr/bin:/sbin:/usr/sbin:/bin:/usr/bin/X11:/usr/X11R6/bin:/usr/games: No such file or directory



Error: gdal-config not found while installing R dependent packages whereas gdal is installed

The data.table has a nice feature that suppresses output to the head and tail of the table.

Is it possible to view / print more than 100 rows at once?

    library(data.table)
    ## Convert the ubiquitous &quot;iris&quot; data to a data.table
    dtIris = as.data.table(iris)
    ## Printing 100 rows is possible
    dtIris[1:100, ]
    ## Printing 101 rows is truncated
    dtIris[1:101, ]

I often have data.table results that are somewhat large (e.g. 200 rows) that I just want to view.


Possible to print more than 100 rows of a data.table?

In R, I have an operation which creates some `Inf` values when I transform a dataframe.  

I would like to turn these `Inf` values into `NA` values.  The code I have is slow for large data, is there a faster way of doing this? 

Say I have the following dataframe: 

    dat &lt;- data.frame(a=c(1, Inf), b=c(Inf, 3), d=c(&quot;a&quot;,&quot;b&quot;))

The following works in a single case: 

     dat[,1][is.infinite(dat[,1])] = NA

So I generalized it with following loop

    cf_DFinf2NA &lt;- function(x)
    {
    	for (i in 1:ncol(x)){
    		  x[,i][is.infinite(x[,i])] = NA
    	}
    	return(x)
    }

But I don&#39;t think that this is really using the power of R. 

Cleaning `Inf` values from an R dataframe

I want to write `trycatch` code to deal with error in downloading from the web.

    url &lt;- c(
        &quot;http://stat.ethz.ch/R-manual/R-devel/library/base/html/connections.html&quot;,
        &quot;http://en.wikipedia.org/wiki/Xz&quot;)
    y &lt;- mapply(readLines, con=url)
    
These two statements run successfully. Below, I create a non-exist web address:

    url &lt;- c(&quot;xxxxx&quot;, &quot;http://en.wikipedia.org/wiki/Xz&quot;)
    
`url[1]` does not exist. How does one write a `trycatch` loop (function) so that:  
  
1. When the URL is wrong, the output will be: &quot;web URL is wrong, can&#39;t get&quot;.  
2. When the URL is wrong, the code does not stop, but continues to download until the end of the list of URLs?

How to write trycatch in R

Given a list of integers, I want to find which number is the closest to a number I give in input:

    &gt;&gt;&gt; myList = [4, 1, 88, 44, 3]
    &gt;&gt;&gt; myNumber = 5
    &gt;&gt;&gt; takeClosest(myList, myNumber)
    ...
    4

Is there any quick way to do this?

From list of integers, get number closest to a given value

I have a list like below where the first element is the id and the other is a string:

    [(1, u&#39;abc&#39;), (2, u&#39;def&#39;)]

I want to create a list of ids only from this list of tuples as below:

    [1,2]

I&#39;ll use this list in `__in` so it needs to be a list of integer values.

How to get first element in a list of tuples?

Is it possible to call method that is defined in `Activity` from `ListAdapter`?

(I want to make a `Button` in `list&#39;s` row and when this button is clicked, it should perform the method, that is defined in corresponding Activity. I tried to set `onClickListener` in my `ListAdapter` but I don&#39;t know how to call this method, what&#39;s its path...) 

when I used `Activity.this.method()` I get the following error:

    No enclosing instance of the type Activity is accessible in scope

Any Idea ?

Call Activity method from adapter

Is there a way to slice only the first and last item in a list?

For example; If this is my list:

    &gt;&gt;&gt; some_list
    [&#39;1&#39;, &#39;B&#39;, &#39;3&#39;, &#39;D&#39;, &#39;5&#39;, &#39;F&#39;]

I *want* to do this (obviously `[0,-1]` is not valid syntax):

    &gt;&gt;&gt; first_item, last_item = some_list[0,-1]
    &gt;&gt;&gt; print first_item
    &#39;1&#39;
    &gt;&gt;&gt; print last_item
    &#39;F&#39;

Some things I have tried:

    In [3]: some_list[::-1]
    Out[3]: [&#39;F&#39;, &#39;5&#39;, &#39;D&#39;, &#39;3&#39;, &#39;B&#39;, &#39;1&#39;]

    In [4]: some_list[-1:1:-1]
    Out[4]: [&#39;F&#39;, &#39;5&#39;, &#39;D&#39;, &#39;3&#39;]
    
    In [5]: some_list[0:-1:-1]
    Out[5]: []
    ...



Python slice first and last element in list

I have a `List&lt;Thing&gt;` and I would like to pass it to a method declared `doIt(final Thing... things)`.  Is there a way to do that?

The code looks *something* like this:

    public doIt(final Thing... things)
    {
        // things get done here
    }

    List&lt;Thing&gt; things = /* initialized with all my things */;

    doIt(things);

That code obviously doesn&#39;t work because `doIt()` takes `Thing` not `List&lt;Thing&gt;`. 

Is there a way to pass in a List as the varargs?

**This is in an Android App, but I don&#39;t see why the solution will not apply to anything Java**

Passing a List in as varargs

I&#39;m familiar with being able to extract columns from an R data frame (or matrix) like so:

    df.2 &lt;- df[, c(&quot;name1&quot;, &quot;name2&quot;, &quot;name3&quot;)]

But can one use a `!` or other tool to select *all but those listed columns*?

For background, I have a data frame with quite a few column vectors and I&#39;d like to avoid:

- Typing out the majority of the names when I could just remove a minority
- Using the much shorter `df.2 &lt;- df[, c(1,3,5)]` because when my .csv file changes, my code goes to heck since the numbering isn&#39;t the same anymore. I&#39;m new to R and think I&#39;ve learned the hard way not to use number vectors for larger df&#39;s that might change.

I tried:

    df.2 &lt;- df[, !c(&quot;name1&quot;, &quot;name2&quot;, &quot;name3&quot;)]
    df.2 &lt;- df[, !=c(&quot;name1&quot;, &quot;name2&quot;, &quot;name3&quot;)]

And just as I was typing this, found out that this works:

    df.2 &lt;- df[, !names(df) %in% c(&quot;name1&quot;, &quot;name2&quot;, &quot;name3&quot;)]

Is there a better way than this last one?

Selecting columns in R data frame based on those *not* in a vector

I want to select rows from a data frame based on partial match of a string in a column, e.g. column &#39;x&#39; contains the string &quot;hsa&quot;. Using `sqldf` - _if_ it had a `like` syntax - I would do something like:

`select * from &lt;&gt; where x like &#39;hsa&#39;`.

Unfortunately, `sqldf` does not support that syntax.

Or similarly:

    selectedRows &lt;- df[ , df$x %like% &quot;hsa-&quot;]

Which of course doesn&#39;t work.

Can somebody please help me with this? 



Selecting data frame rows based on partial string match in a column

I&#39;ve been encountering what I think is a bug.  It&#39;s not a big deal, but I&#39;m curious if anyone else has seen this.  Unfortunately, my data is confidential, so I have to make up an example, and it&#39;s not going to be very helpful.

When subsetting my data, I occassionally get mysterious NA rows that aren&#39;t in my original data frame.  Even the rownames are NA.  EG:

    example &lt;- data.frame(&quot;var1&quot;=c(&quot;A&quot;, &quot;B&quot;, &quot;A&quot;), &quot;var2&quot;=c(&quot;X&quot;, &quot;Y&quot;, &quot;Z&quot;))
    example

      var1 var2
    1    A    X
    2    B    Y
    3    A    Z

then I run:

    example[example$var1==&quot;A&quot;,]

      var1 var2
    1    A    X
    3    A    Z
    NA&lt;NA&gt; &lt;NA&gt;

Of course, the example above does not actually give you this mysterious NA row; I am adding it here to illustrate the problem I&#39;m having with my data.

Maybe it has to do with the fact that I&#39;m importing my original data set using &lt;a href=&quot;http://cran.r-project.org/web/packages/xlsx/xlsx.pdf&quot;&gt;Google&#39;s read.xlsx package &lt;/a&gt; and then executing wide to long reshape before subsetting.

Thanks

Subsetting R data frame results in mysterious NA rows

I have two data sets that are supposed to be the same size but aren&#39;t. I need to trim the values from A that are not in B and vice versa in order to eliminate noise from a graph that&#39;s going into a report. (Don&#39;t worry, this data isn&#39;t being permanently deleted!)

I have read the following:

 - https://stackoverflow.com/questions/12208090/selecting-columns-in-r-data-frame-based-on-those-not-in-a-vector
 - http://www.ats.ucla.edu/stat/r/faq/subset_R.htm
 - https://stackoverflow.com/questions/4935479/how-to-combine-multiple-conditions-to-subset-a-data-frame-using-or

But I&#39;m still not able to get this to work right. Here&#39;s my code:

    bg2011missingFromBeg &lt;- setdiff(x=eg2011$ID, y=bg2011$ID)
    #attempt 1
    eg2011cleaned &lt;- subset(eg2011, ID != bg2011missingFromBeg)
    #attempt 2
    eg2011cleaned &lt;- eg2011[!eg2011$ID %in% bg2011missingFromBeg]

The first try just eliminates the first value in the resulting setdiff vector. The second try yields and unwieldy error:

    Error in `[.data.frame`(eg2012, !eg2012$ID %in% bg2012missingFromBeg) 
    :  undefined columns selected


Subset rows in a data frame based on a vector of values

I have a problem to plot a subset of a data frame with ggplot2. My df is like:

```r
df = data.frame(ID = c(&#39;P1&#39;, &#39;P1&#39;, &#39;P2&#39;, &#39;P2&#39;, &#39;P3&#39;, &#39;P3&#39;),
                Value1 = c(100, 120, 300, 400, 130, 140),
                Value2 = c(12, 13, 11, 16, 15, 12))
```

How can I now plot `Value1` vs `Value2` only for `ID`s `&#39;P1&#39;` and `&#39;P3&#39;`?
For example I tried:

```r
ggplot(subset(df,ID==&quot;P1 &amp; P3&quot;) +
  geom_line(aes(Value1, Value2, group=ID, colour=ID)))
```

but I always receive an error.

Content Type	Original Author	Original Content on Stackoverflow
Question	user1357015	View Question on Stackoverflow
Solution 1 - R	Glen_b	View Answer on Stackoverflow

Select multiple elements from a list

R Problem Overview

R Solutions

Solution 1 - R

Execute ssh with password authentication via windows command prompt

Android - Preventing WebView reload on Rotate

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