[R] barplot that displays sums of values of 2 y colums grouped by different variables

[kenneth dyson]

Thanks everyone.

Got it to work like this, if anyone is interested:

import the data with readr, taking in only the columns that have numeric 
values ("n" and "y") and the column with the groups ("city").

aggregate the data by the group ("city") so that each variable has a sum:

|sum_data <-aggregate(.~City__c,data=raw_data,sum)|

reshape the data so that the groups are now variables (there will be 3 
columns: "city", "variable", "value"):

|library(reshape2)library(ggplot2)sums <-melt(sum_data)|

plot using ggplot:

|ggplot(sums,aes(x =city,y=value,fill =variable,ymax 
=1000))+geom_bar(stat="identity",width=.8,position ="dodge")|


On 2018-01-15 6:01 PM, Jeff Newmiller wrote:
> It is not generally advisable to get too fancy with stat functions in 
> ggplot... things can easily get more complicated than ggplot is ready 
> to handle when it comes to calculations. It is better to create data 
> that corresponds directly to the graphical representations you are 
> mapping them to.
>
> Read [1] for more on this philosophy.
>
> [1] H. Wickham, Tidy Data, Journal of Statistical Software, vol. 59, 
> no. 10, pp. 123, Sep. 2014. http://www.jstatsoft.org/v59/i10/
>
> #---
> library(ggplot2) # ggplot
> library(dplyr)   # `%>%`, group_by, summarise
> #> Attaching package: 'dplyr'
> #> The following objects are masked from 'package:stats':
> #>
> #>     filter, lag
> #> The following objects are masked from 'package:base':
> #>
> #>     intersect, setdiff, setequal, union
> library(tidyr)   # gather
>
> dta <- read.table( text =
> "city n y
> mon 100 200
> tor 209 300
> edm 98 87
> mon 20 76
> tor 50 96
> edm 62 27
> ", header = TRUE )
>
> dta2 <- (   dta
>         %>% group_by( city )
>         %>% summarise( n = sum( n )
>                      , y = sum( y )
>                      )
>         %>% gather( Response, value, -city )
>         )
>
> ggplot( dta2, aes( x=city, y=value, fill = Response ) ) +
>     geom_bar( stat="identity", position="dodge" )
>
> #' ![](https://i.imgur.com/cosFf3B.png)
> #---
>
> On Mon, 15 Jan 2018, kenneth dyson wrote:
>
>> I am trying to create a barplot displaying the sums of 2 columns of 
>> data grouped by a variable. the data is set up like this:
>>
>> "city" "n" "y" <br>
>> mon 100 200 <br>
>> tor 209 300 <br>
>> edm 98 87 <br>
>> mon 20 76 <br>
>> tor 50 96 <br>
>> edm 62 27 <br>
>>
>> the resulting plot should have city as the x-axis, 2 bars per city, 1 
>> representing the sum of "n" in that city, the other the sum of "y" in 
>> that city.
>>
>> If possible also show the sum in each bar as a label?
>>
>> I aggregated the data into sums like this:
>>
>> sum_data <- aggregate(. ~ City,data=raw_data,sum)
>>
>> this gave me the sums per city as I wanted but for some reason 1 of 
>> the cities is missing in the output.
>>
>> Using this code for the plot:
>>
>> ggplot(sum_data,aes(x = City,y = n)) + geom_bar(aes(fill = y),stat = 
>> "identity",position = "dodge")
>>
>> gave be a bar plot with one bar per city showing the sum of y as a 
>> color gradient. not what I expected given the "dodge" command in 
>> geom_bar.
>>
>> Thanks.
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide 
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
> --------------------------------------------------------------------------- 
>
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