You got this error because `p` values are numeric in your data frame but in this case for the `fill=` you need discrete values as bars are stacked and will be colored according to `p`. Just use `as.factor()` around `p`.

    ggplot(BCIcor,aes(x=cor,fill=as.factor(p)))+geom_histogram(binwidth = 0.2)

In a table xyz I have a row called components and a labref row which has labref number as shown here
    
Table xyz

    labref             component
    NDQA201303001          a
    NDQA201303001          a
    NDQA201303001          a
    NDQA201303001          a
    NDQA201303001          b
    NDQA201303001          b
    NDQA201303001          b
    NDQA201303001          b
    NDQA201303001          c
    NDQA201303001          c
    NDQA201303001          c
    NDQA201303001          c

I want to group the components then count the rows returned which equals to 3, I have written the below SQL query but it does not help achieve my goal instead it returns 4 for each component

    SELECT DISTINCT component, COUNT( component ) 
    FROM `xyz`
    WHERE labref = &#39;NDQA201303001&#39;
    GROUP BY component

The query returns

Table xyz


    labref         component   COUNT(component)       
    NDQA201303001   a           4
    NDQA201303001   b           4
    NDQA201303001   c           4

 
What I want to achieve now is that from the above result, the rows are counted and 3  is returned as the number of rows, Any workaround is appreciated


Counting number of grouped rows in mysql

I am trying to use the report viewer in asp.net and have uploaded my site. However, when my page containing the report viewer is loaded, it shows the following error:
 
&gt; Could not load file or assembly &#39;Microsoft.ReportViewer.WebForms, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91&#39; or one of its dependencies. The located assembly&#39;s manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)


This is my first time deploying an ASP.NET website, so I&#39;m not sure what the problem is.

Could not load file or assembly &#39;Microsoft.ReportViewer.WebForms&#39;

When using `geom_histogram` there is error 

    unit(tic_pos.c, &quot;mm&quot;) : &#39;x&#39; and &#39;units&#39; must have length &gt; 0. 

Why?

    p4&lt;-ggplot(BCIcor,aes(x=cor))+geom_histogram(binwidth = 0.2)    
This showed a black bar chart. However, when I wanted to group the data by `p` to make the plot colorful, I added `fill=p`,

    p4&lt;-ggplot(BCIcor,aes(x=cor,fill=p))+geom_histogram(binwidth = 0.2)
The I got the following:

    error :&quot;unit(tic_pos.c, &quot;mm&quot;) : &#39;x&#39; and &#39;units&#39; must have length &gt; 0&quot;.

What&#39;s wrong??

The data frame is: 

 

 

      cor        pvalue   p 
    
    1  0.87882370 0.049710 2       
    2 -0.83041880 0.081660 1         
    3 -0.12989750 0.835100 1        
    4 -0.75309860 0.141700 1        
    5 -0.88553450 0.045680 2



When using &quot;geom_histogram&quot; there is error &quot;unit(tic_pos.c, &quot;mm&quot;) : &#39;x&#39; and &#39;units&#39; must have length &gt; 0&quot;. Why

When using <code>geom_histogram</code> there is error
<pre><code class="hljs language-perl">unit(tic_pos.c, "mm") : 'x' and 'units' must have length > 0. 
</code></pre>
Why?
<pre><code class="hljs language-scss">p4&#x3C;-ggplot(BCIcor,aes(x=cor))+geom_histogram(binwidth = 0.2) 
</code></pre>
This showed a black bar chart. However, when I wanted to group the data by <code>p</code> to make the plot colorful, I added <code>fill=p</code>,
<pre><code class="hljs language-scss">p4&#x3C;-ggplot(BCIcor,aes(x=cor,fill=p))+geom_histogram(binwidth = 0.2)
</code></pre>
The I got the following:
<pre><code class="hljs language-go">error :"unit(tic_pos.c, "mm") : 'x' and 'units' must have length > 0".
</code></pre>
What's wrong??
The data frame is:
<pre><code class="hljs language-css"> cor pvalue p 

1 0.87882370 0.049710 2 
2 -0.83041880 0.081660 1 
3 -0.12989750 0.835100 1 
4 -0.75309860 0.141700 1 
5 -0.88553450 0.045680 2
</code></pre>

Assume I have a `data.table` containing some baseball players:

    library(plyr)
    library(data.table)

    bdt &lt;- as.data.table(baseball)

For each group (given by player &#39;id&#39;), I want to select rows corresponding to the maximum number of games &#39;g&#39;. This is straightforward in `plyr`:

    ddply(baseball, &quot;id&quot;, subset, g == max(g))

What&#39;s the equivalent code for `data.table`?

I tried:

    setkey(bdt, &quot;id&quot;) 
    bdt[g == max(g)]  # only one row
    bdt[g == max(g), by = id]  # Error: &#39;by&#39; or &#39;keyby&#39; is supplied but not j
    bdt[, .SD[g == max(g)]] # only one row

This works:

    bdt[, .SD[g == max(g)], by = id] 


But it&#39;s is only 30% faster than `plyr`, suggesting it&#39;s probably not idiomatic.

Subset rows corresponding to max value by group using data.table

I have a need that I imagine could be satisfied by `aggregate` or `reshape`, but I can&#39;t quite figure out.

I have a list of names (`brand`), and accompanying ID number (`id`).  This data is in long form, so names can have multiple ID&#39;s.  I&#39;d like to de-dupicate by the name (`brand`) and concatenate the multiple possible `id`&#39;s into a string separated by a comment.

For example: 

    brand            id 
    RadioShack	     2308
    Rag &amp; Bone	     4466
    Ragu	         1830
    Ragu	         4518
    Ralph Lauren	 1638
    Ralph Lauren	 2719
    Ralph Lauren	 2720
    Ralph Lauren	 2721
    Ralph Lauren	 2722 

should become:

    RadioShack	     2308
    Rag &amp; Bone	     4466
    Ragu	         1830,4518
    Ralph Lauren	 1638,2719,2720,2721,2722

How would I accomplish this?

Aggregating by unique identifier and concatenating related values into a string

I&#39;m trying to control the position of a plot when converting to PDF using knitr and pandoc. My .Rmd file looks this:

    # My report
    
    Some text some text some text some text some text some text some text some text some text
    
    
    ```{r myplot, echo=FALSE, fig.pos=&quot;placeHere&quot;, results=&#39;hide&#39;}
    
    library(ggplot2)
    
    ggplot(mtcars, aes(mpg, drat)) + geom_point()
    
    ```
    
    Some text some text some text some text some text some text some text some text some text
    
    \usepackage{graphicx}
    \begin{figure}[placeHere]
      \centering
        \includegraphics[width=0.5\textwidth]{placeHere}
    \end{figure}
    
    Some text some text some text some text some text some text some text some text some text


I&#39;m converting to PDF using the functions provided here: http://quantifyingmemory.blogspot.co.uk/2013/02/reproducible-research-with-r-knitr.html

How can I place the plot between the second and third blocks of text? The latex code is not working as it currently stands.

**EDIT:** This is what I&#39;m trying now.

    # My report
    
       ```{r setup, include=FALSE}
    # set global chunk options
    opts_chunk$set(cache=FALSE)
    library(ggplot2)
    ```
    
    ```{r, echo=FALSE, fig.height=3}
    
    ggplot(mtcars, aes(disp, hp)) + geom_point()
    
    
    ```
    
    
    
    Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some textSome text Some text Some text 
    
    Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some textSome text Some text Some text 
    
    
    Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some textSome text Some text Some text 
    
    
    Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some textSome text Some text Some text 
    
    
    ```{r, echo=FALSE, fig.height=3}
    
    
    
    ggplot(mtcars, aes(vs, am)) + geom_point()
    
    
    ```
    
    
    
    Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some textSome text Some text Some text 
    
    Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some textSome text Some text Some text 
    
    
    Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some textSome text Some text Some text 
    
    
    ```{r, echo=FALSE, fig.height=6}
    
    
    
    ggplot(mtcars, aes(disp, cyl)) + geom_point()
    
    ```
    
    
    ```{r, echo=FALSE, fig.height=6}
    
    ggplot(mtcars, aes(hp, qsec)) + geom_point()
    
    
    ```
    
    
    Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some textSome text Some text Some text 
    
    
    
    
    ```{r, echo=FALSE, fig.height=3}
    
    ggplot(mtcars, aes(hp, wt)) + geom_point()
    
    ```
    
    
    
    Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some textSome text Some text Some text 
    
    
    
    ```{r, echo=FALSE, fig.height=5}
    
    ggplot(mtcars, aes(mpg, drat)) + geom_point()
    
    ```
    
    
    
    
    Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some text Some textSome text Some text Some text 

Figure position in markdown when converting to PDF with knitr and pandoc

What&#39;s the correct way to remove multiple columns from a data.table?  I&#39;m currently using the code below, but was getting unexpected behavior when I accidentally repeated one of the column names.  I wasn&#39;t sure if this was a bug, or if I shouldn&#39;t be removing columns this way.
   
    library(data.table)
    DT &lt;- data.table(x = letters, y = letters, z = letters)
    DT[ ,c(&quot;x&quot;,&quot;y&quot;) := NULL]
    names(DT)
    [1] &quot;z&quot;

The above works fine, but

    DT &lt;- data.table(x = letters, y = letters, z = letters)
    DT[ ,c(&quot;x&quot;,&quot;x&quot;) := NULL]
    names(DT)
    [1] &quot;z&quot;

Remove multiple columns from data.table

If I have a data frame

    set.seed(12345) 
    df=data.frame(a=rnorm(5),b=rnorm(5))

I can add a row by e.g.

`df[6,] =c(5,6)`

If I now do the equivalent in data.table

    library(data.table)
    dt=data.table(df)
    dt[6,]=c(5,6)

It fails with an error. What is the right way to insert a row into a data.table?


Insert a row in a data.table

I&#39;ve been battling to order and plot a simple dataframe as a bar chart in ggplot2.  

I want to plot the data as it appears, so that the values (&#39;count&#39; variable) for the corresponding categories (e.g. &#39;humans&#39;, &#39;male&#39;) are plotted from high to low. 

I&#39;ve followed other threads on this site asking similar questions, but can&#39;t get this to work!

    ## Dataset (mesh2)

    #Category			        Count

    #Humans				62

    #Male				40

    #Female				38

    #Adult				37

    #Middle Aged			30

    #Liver/anatomy &amp; histology	        29

    #Organ Size			        29

    #Adolescent			        28

    #Child				21

    #Liver/radiography*		        20

    #Liver Transplantation*		20

    #Tomography, X-Ray Computed	        20

    #Body Weight			18

    #Child, Preschool		        18

    #Living Donors*			18

    #Infant				16

    #Aged				14

    #Body Surface Area		        14

    #Regression Analysis		11

    #Hepatectomy			10

    ## read in data (mesh2) as object (mesh2)

    mesh2 &lt;- read.csv(&quot;mesh2.csv&quot;, header = T)

    ## order data by count of mesh variable

    mesh2$cat2 &lt;- order(mesh2$Category, mesh2$Count, decreasing=TRUE)

    ## Barplot created in ggplot2

    library(ggplot2)

    mesh2p &lt;- ggplot(mesh2, aes(x=cat2, y=Count)) + geom_bar (stat=&quot;identity&quot;) +     scale_x_continuous(breaks=c(1:20), labels=c(&quot;Humans&quot;, &quot;Male&quot;, &quot;Female&quot;, &quot;Adult&quot;, &quot;MAged&quot;,   &quot;Liver anat &amp; hist&quot;, &quot;Organ Size&quot;, &quot;Adolescent&quot;,	&quot;Child&quot;, &quot;Liver radiog&quot;, &quot;Liver Transplnt&quot;, &quot;Tomog X-Ray Computed&quot;, &quot;Body Weight&quot;, &quot;Child Preschool&quot;, &quot;Living Donors&quot;, &quot;Infant&quot;, &quot;Aged&quot;, &quot;BSA&quot;,	&quot;Regression Analysis&quot;, &quot;Hepatectomy&quot;))+ theme (axis.text.x=element_text(angle=45, hjust=1))

Plot data in descending order as appears in data frame

I am trying to plot multiple plots using `ggplot2`, arranging them using `grid.arrange()`.
Since I managed to find someone describing the exact problem I have, I have quoted from the problem description from [link](https://groups.google.com/forum/?fromgroups#!topic/ggplot2/AsIcHtouIyY):




When I use `ggsave()` after `grid.arrange()`, i.e.

&gt;     grid.arrange(sgcir1,sgcir2,sgcir3,ncol=2,nrow=2)
&gt;     ggsave(&quot;sgcirNIR.jpg&quot;)


I do not save the grid plot but the last individual ggplot. Is there any
way of actually saving the plot as displayed by `grid.arrange()` using
`ggsave()` or something similar?
Other than using the older way


&gt;     jpeg(&quot;sgcirNIR.jpg&quot;)
&gt;     grid.arrange(sgcir1,sgcir2,sgcir3,ncol=2,nrow=2)
&gt;     dev.off()

The same link gives the solution below:

    require(grid)
    require(gridExtra)
    p &lt;- arrangeGrob(qplot(1,1), textGrob(&quot;test&quot;))
    grid.draw(p) # interactive device
    ggsave(&quot;saving.pdf&quot;, p) # need to specify what to save explicitly

However, I can&#39;t figure out how to use `ggsave()` to save the output of the `grid.arrange()` call in the following code, which is taken from [link](https://github.com/hadley/ggplot2/wiki/Share-a-legend-between-two-ggplot2-graphs):

    library(ggplot2)
    library(gridExtra)
    dsamp &lt;- diamonds[sample(nrow(diamonds), 1000), ] 
    
    p1 &lt;- qplot(carat, price, data=dsamp, colour=clarity)
    p2 &lt;- qplot(carat, price, data=dsamp, colour=clarity, geom=&quot;path&quot;)
    
    g_legend&lt;-function(a.gplot){
    tmp &lt;- ggplot_gtable(ggplot_build(a.gplot))
    leg &lt;- which(sapply(tmp$grobs, function(x) x$name) == &quot;guide-box&quot;)
    legend &lt;- tmp$grobs[[leg]]
    return(legend)}
    
    legend &lt;- g_legend(p1)
    lwidth &lt;- sum(legend$width)
    
    ## using grid.arrange for convenience
    ## could also manually push viewports
    grid.arrange(arrangeGrob(p1 + theme(legend.position=&quot;none&quot;),
                                            p2 + theme(legend.position=&quot;none&quot;),
                                            main =&quot;this is a title&quot;,
                                            left = &quot;This is my global Y-axis title&quot;), legend, 
                         widths=unit.c(unit(1, &quot;npc&quot;) - lwidth, lwidth), nrow=1)
    
    # What code to put here to save output of grid.arrange()?

Saving grid.arrange() plot to file

I cannot figure out how to manually set up a legend for this plot. All I really want is a simple legend to the right that uses the three colors and has a name next to each.

![enter image description here][1]

The current code looks like this: 

    a &lt;-c(&quot;S1&quot;,&quot;S2&quot;,&quot;S3&quot;,&quot;S4&quot;,&quot;S5&quot;,&quot;S6&quot;,&quot;S7&quot;,&quot;S8&quot;,&quot;S9&quot;) #names
    b &lt;-c(0.23,0.26,0.55,0.56,0.36,0.23,0.18,0.06,0.04) #mean t0
    c &lt;-c(0.64,0.6,0.81,1.4,0.89,0.55,0.48,0.22,0.09) #mean t1
    d &lt;-c(0.20,0.23,0.52,0.53,0.33,0.20,0.15,0.04,0.03) #SD low t0
    e &lt;-c(0.26,0.29,0.58,.59,0.39,0.26,0.21,0.08,0.05) #SD high t0
    f &lt;-c(0.67,0.63,0.86,1.44,0.93,0.59,0.51,0.25,0.10) #SD high t1
    g &lt;-c(0.61,0.57,0.78,1.36,0.85,0.53,0.45,0.19,0.08) #SD low t1
    h &lt;-c(0.41,0.34,0.26,0.84,0.53,0.32,0.30,0.16,0.05) #absolute change
    
    data &lt;- data.frame(a,b,c,d,e,f,g,h)
    
    ggplot(data=data,aes(a)) + 
      geom_bar(stat=&quot;identity&quot;, aes(y=h),fill=&quot;#62c76b&quot;,colour=&quot;#333333&quot;)+ #green
      geom_line(aes(y=b,group=1),size=1.0,colour=&quot;#f04546&quot;) +   #red
      geom_point(aes(y=b),size=3, colour=&quot;#f04546&quot;) +           #red
      geom_errorbar(aes(ymin=d, ymax=e), colour=&quot;#f04546&quot;, width=0.1, size=.8) + 
      geom_line(aes(y=c,group=1),size=1.0,colour=&quot;#3591d1&quot;) +   #blue 
      geom_point(aes(y=c),size=3, colour=&quot;#3591d1&quot;) +           #blue
      geom_errorbar(aes(ymin=f, ymax=g), colour=&quot;#3591d1&quot;, width=0.1, size=.8) + 
      ylab(&quot;Symptom severity&quot;) + xlab(&quot;PHQ-9 symptoms&quot;) +
      ylim(0,1.6) +
      theme_bw() +
      theme(axis.title.x = element_text(size = 15, vjust=-.2)) +
      theme(axis.title.y = element_text(size = 15, vjust=0.3))




  [1]: http://i.stack.imgur.com/xYukB.png

Construct a manual legend for a complicated plot

I have a data set from which I have to make several dozen plots. 
The data consists of 30 Groups and several measurements within each group. 

Most plots will not use all the groups at once. 

My goal is to have one single color pallete for the set of groups such that any given group is the same color across all graphs. 
In the example below, this would mean that `Group C` is the same color in `Plot 1` and in `Plot 2`. 

My question is how to go about this.  

I&#39;ve tried several variations of scale_fill_manual  (and scal_color_manual, when appropriate).  While the colors are chosen from the designated pallete, 
I cannot seem to index the pallette by the group, or some other way to &quot;skip&quot; over the colors corresponding to a missing group

I also thought to try to add the color information as a column of the data being plotted, but I&#39;m unsure how to then use this column as the color for the group. 

![Plot Example][2]


    library(ggplot2)
    library(data.table)

    # SAMPLE DATA: 
    DT1 &lt;- data.table(Name=c(&quot;C_sub1&quot;, &quot;A_sub1&quot;, &quot;A_sub2&quot;), Value=c(2,5,3), Group=c(&quot;C&quot;, &quot;A&quot;, &quot;A&quot;), key=&quot;Group&quot;)
    DT2 &lt;- data.table(Name=c(&quot;A_sub1&quot;, &quot;B_sub1&quot;, &quot;C_sub1&quot;, &quot;C_sub2&quot;), Value=c(4,3,6,3), Group=c(&quot;A&quot;, &quot;B&quot;, &quot;C&quot;, &quot;C&quot;), key=&quot;Group&quot;)

    # SAMPLE Color Pallette  
    ColorsDT &lt;-  data.table(Group=LETTERS[1:5], Color=c(&quot;#333BFF&quot;, &quot;#CC6600&quot;, &quot;#9633FF&quot;, &quot;#E2FF33&quot;, &quot;#E3DB71&quot;), key=&quot;Group&quot;)

    # Add a column for Color, according to the Group
    DT1[ColorsDT, Color := i.Color]
    DT2[ColorsDT, Color := i.Color]

    # A Basic Plot
    simplePlot &lt;- function(DT, tit) 
      ggplot(DT ,aes(x=Name, y=Value, fill=Group)) +
       geom_bar(stat=&quot;identity&quot;) + xlab(&quot;&quot;) + ggtitle(tit)
        # Tried sevearl variations of: 
        #  + scale_fill_manual(values=ColorsDT$Color)


    # Plot Them
    grid.arrange(ncol=2,  simplePlot(DT1, tit=&quot;Plot 1&quot;),  simplePlot(DT2, tit=&quot;Plot 2&quot;))


  [2]: http://i.stack.imgur.com/3NQ7D.png

Manually setting group colors for ggplot2

Using geom_text to label outlying points of scatter plot. 
By definition, these points tend to be close to the canvas edges: there is usually at least one word that overlaps the canvas edge, rendering it useless.

Clearly this can be solved manually in the case below using `+ xlim(c(1.5, 4.5))`:

    # test
    df &lt;- data.frame(word = c(&quot;bicycle&quot;, &quot;tricycle&quot;, &quot;quadricycle&quot;),
                     n.wheels = c(2,3,4),
                     utility = c(10,6,7))
    ggplot(data=df, aes(x=n.wheels, y=utility, label=word))  + geom_text() + xlim(c(1.5, 4.5))

![trike][1]

This is not ideal though, as 

 1. It&#39;s not automated, so slows down the process if many plots are to be produced
 2. It&#39;s not accurate, meaning the distance between the edge of the word and the edge of the canvas is not equal in every case.

Searches for this problem reveal no solutions, and Hadley Wickham seems to be content with labels being cut in half in ggplot2&#39;s [help page][2] (I know Hadley, they&#39;re just an examples ;)


  [1]: http://i.stack.imgur.com/LMcD1.png
  [2]: http://docs.ggplot2.org/current/geom_text.html

Content Type	Original Author	Original Content on Stackoverflow
Question	Jada	View Question on Stackoverflow
Solution 1 - R	Didzis Elferts	View Answer on Stackoverflow

When using "geom_histogram" there is error "unit(tic_pos.c, "mm") : 'x' and 'units' must have length > 0". Why

R Problem Overview

R Solutions

Solution 1 - R

Could not load file or assembly 'Microsoft.ReportViewer.WebForms'

Counting number of grouped rows in mysql

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