Add a `+ guides(colour = guide_legend(override.aes = list(size=10)))` to the plot. You can play with the `size` argument. 

I want to insert data into 3 tables with a single query.  
My tables looks like below:

    CREATE TABLE sample (
       id        bigserial PRIMARY KEY,
       lastname  varchar(20),
       firstname varchar(20)
    );

    CREATE TABLE sample1(
       user_id    bigserial PRIMARY KEY,
       sample_id  bigint REFERENCES sample,
       adddetails varchar(20)
    );
    
    CREATE TABLE sample2(
       id      bigserial PRIMARY KEY,
       user_id bigint REFERENCES sample1,
       value   varchar(10)
    );

I will get a key in return for every insertion and I need to insert that key in the next table.  
My query is:

    insert into sample(firstname,lastname) values(&#39;fai55&#39;,&#39;shaggk&#39;) RETURNING id;
    insert into sample1(sample_id, adddetails) values($id,&#39;ss&#39;) RETURNING user_id;
    insert into sample2(user_id, value) values($id,&#39;ss&#39;) RETURNING id;

But if I run single queries they just return values to me and I cannot reuse them in the next query immediately.

How to achieve this?

Insert data in 3 tables at a time using Postgres

I have several [Express][1] applications, and I see that in some modules, [`res.end()`][2] is called at the end of a request handler (after [`res.send`][3] or [`res.json`][4]), while in others, it isn&#39;t called.

For example:

    app.get(&#39;/test&#39;, function(req, res) {
        res.send(&#39;Test&#39;, 200);
    });

or:

    app.get(&#39;/test&#39;, function(req, res) {
        res.send(&#39;Test&#39;, 200);
        res.end();
    });


Both cases work, but I&#39;m afraid about leaks or running out file descriptors or something like that, when I run many requests. Which one is &quot;more correct&quot;?

  [1]: http://expressjs.com/
  [2]: http://expressjs.com/4x/api.html#res.end
  [3]: http://expressjs.com/4x/api.html#res.send
  [4]: http://expressjs.com/4x/api.html#res.json

Must res.end() be called in express with node.js?

I have thousands of points in one figure and set `size = 1`. However, the point size in the legend is reduced too. How to increase the point size in the legend?

For example.

    num &lt;- 10000
    set.seed(1)
    df &lt;- data.frame(x = seq(1, num), y = runif(num), z = rep(1:2, each = num / 2))
    df$z &lt;- factor(df$z)
    library(ggplot2)
    p &lt;- ggplot(df, aes(x, y, colour = z)) + geom_point(size = 1)
    p

![The size of points in legend][1]

  [1]: http://i.stack.imgur.com/1W6GX.png

How to increase the size of points in legend of ggplot2?

I have thousands of points in one figure and set <code>size = 1</code>. However, the point size in the legend is reduced too. How to increase the point size in the legend?
For example.
<pre><code class="hljs language-scss">num &#x3C;- 10000
set.seed(1)
df &#x3C;- data.frame(x = seq(1, num), y = runif(num), z = rep(1:2, each = num / 2))
df$z &#x3C;- factor(df$z)
library(ggplot2)
p &#x3C;- ggplot(df, aes(x, y, colour = z)) + geom_point(size = 1)
p
</code></pre>
<img src="http://i.stack.imgur.com/1W6GX.png" alt="The size of points in legend">

Let&#39;s say I have a list like this:

    x = list(list(1,2), list(3,4), list(5,6))

I would like a list that contains only the first elements of the nested list. I can do this by returning another list like so

    x1 = lapply(x, function(l) l[[1]])

Is there shortcut notation for this?

Select first element of nested list

I&#39;m trying to install R using Homebrew. I ran these commands which are recommended elsewhere on SO:

    brew tap homebrew/science
    brew install R

For `brew tap homebrew/science`, I&#39;m receiving this error:

    Error: Already tapped!

For the second command, I receive this:

    Error: No available formula for r 

Any suggestions?



Installing R with Homebrew

I&#39;ve been reading the `ggplot2` documentation for both functions. I was wondering what were the differences and what would be right situation for using each function (`facet_wrap()` and `facet_grid()`). 

    library(ggplot2)

    p &lt;- qplot(displ, hwy, data = mpg)
    p + facet_wrap(~ cyl)
    
    p + facet_grid(~ cyl)

I provide this small example to serve as starting point. The difference seems to be wrap makes the plots more autonomous and grid makes one plot all together.


What&#39;s the difference between facet_wrap() and facet_grid() in ggplot2?

**Edit:** This question has been marked as duplicated, but the responses [here][1] have been tried and did not work because the case in question is a line chart, not a bar chart. Applying those methods produces a chart with 5 lines, 1 for each year - not useful. Did anyone who voted to mark as duplicate actually try those approaches on the sample dataset supplied with this question? If so please post as an answer.

**Original Question:**

There&#39;s a feature in Excel pivot charts which allows multilevel categorical axes.I&#39;m trying to find a way to do the same thing with `ggplot` (or any other plotting package in R).

Consider the following dataset:

    set.seed(1)
    df=data.frame(year=rep(2009:2013,each=4),
                  quarter=rep(c(&quot;Q1&quot;,&quot;Q2&quot;,&quot;Q3&quot;,&quot;Q4&quot;),5),
                  sales=40:59+rnorm(20,sd=5))

If this is imported to an Excel pivot table, it is straightforward to create the following chart:

![][2]

Note how the x-axis has two levels, one for quarter and one for the grouping variable, year. Are multilevel axes possible with `ggplot`?

NB: There is a hack with facets that produces something similar, but this is not what I&#39;m looking for.

    library(ggplot2)
    ggplot(df) +
      geom_line(aes(x=quarter,y=sales,group=year))+
      facet_grid(.~year,scales=&quot;free&quot;)

![][3]


  [1]: https://stackoverflow.com/questions/18165863/ggplot2-labels-of-grouping-values-below-the-plot
  [2]: http://i.stack.imgur.com/XBDhQ.png
  [3]: http://i.stack.imgur.com/s4yXK.png

Multi-row x-axis labels in ggplot line chart

I would like to divide each **row** of a matrix by a fixed vector. For example 

    mat&lt;-matrix(1,ncol=2,nrow=2,TRUE)
    dev&lt;-c(5,10)

Giving `mat/dev` divides each **column** by `dev`. 

         [,1] [,2]
    [1,]  0.2  0.2
    [2,]  0.1  0.1

However, I would like to have this as a result, i.e. do the operation **row-wise** :

    rbind(mat[1,]/dev, mat[2,]/dev)

         [,1] [,2]
    [1,]  0.2  0.1
    [2,]  0.2  0.1

Is there an explicit command to get there?



How to divide each row of a matrix by elements of a vector in R

By using R, is it possible to place 2 ggplot together (i.e., on the same plot)? I wish to show a trend from 2 different data frames and instead of putting them one next to the other, I&#39;d like to integrate them together in one plot and only to change the color of one of them (the black dot).

To be more specific, I have the following 2 visuals:

    ggplot(visual1, aes(ISSUE_DATE,COUNTED)) + geom_point() + geom_smooth(fill=&quot;blue&quot;, colour=&quot;darkblue&quot;, size=1)

and

    ggplot(visual2, aes(ISSUE_DATE,COUNTED)) + geom_point() + geom_smooth(fill=&quot;red&quot;, colour=&quot;red&quot;, size=1)

They look like this (both have black dots and I&#39;ll need to change one of them to something different):


![enter image description here][1]


and

![enter image description here][2]


  [1]: http://i.stack.imgur.com/sDdJm.png
  [2]: http://i.stack.imgur.com/DBNLZ.png

How to combine 2 plots (ggplot) into one plot?

I would like to automatically wrap my labels in ggplot2, i.e. insert line breaks of long labels. [Here][1] is written how to write a function (1) for it, but sadly I do not know where to put `labeller=label_wrap` in my code (2).

(1) function by hadley

    label_wrap &lt;- function(variable, value) {
      lapply(strwrap(as.character(value), width=25, simplify=FALSE), 
             paste, collapse=&quot;\n&quot;)
    }

    
(2) code example

    df = data.frame(x = c(&quot;label&quot;, &quot;long label&quot;, &quot;very, very long label&quot;), 
                    y = c(10, 15, 20))

    ggplot(df, aes(x, y)) + geom_bar(stat=&quot;identity&quot;)
[![Histogram with long label not wrapped][2]][2]

I&#39;d like to wrap some of the longer labels here.

  [1]: https://github.com/hadley/ggplot2/wiki/labeller
  [2]: http://i.stack.imgur.com/BBPRW.png

Wrap long axis labels via labeller=label_wrap in ggplot2

I have a ggplot command

    ggplot( rates.by.groups, aes(x=name, y=rate, colour=majr, group=majr) )

inside a function. But I would like to be able to use a parameter of the function to pick out the column to use as colour and group. I.e. I would like something like this

    f &lt;- function( column ) {
        ...
        ggplot( rates.by.groups, aes(x=name, y=rate, colour= ??? , group=??? ) )
    }

So that the column used in the ggplot is determined by the parameter. E.g. for f(&quot;majr&quot;) we get the effect of

    ggplot( rates.by.groups, aes(x=name, y=rate, colour=majr, group=majr) )

but for f(&quot;gender&quot;) we get the effect of

      ggplot( rates.by.groups, aes(x=name, y=rate, colour=gender, group=gender) )

Some things I tried:

    ggplot( rates.by.groups, aes(x=name, y=rate, colour= columnName , group=columnName ) )


did not work. Nor did 

    e &lt;- environment() 
    ggplot( rates.by.groups, aes(x=name, y=rate, colour= columnName , group=columnName ), environment=e )

Content Type	Original Author	Original Content on Stackoverflow
Question	Bangyou	View Question on Stackoverflow
Solution 1 - R	TheComeOnMan	View Answer on Stackoverflow

How to increase the size of points in legend of ggplot2?

R Problem Overview

R Solutions

Solution 1 - R

Must res.end() be called in express with node.js?

Insert data in 3 tables at a time using Postgres

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