title: sum of values for multiple rows with same name in r
body: <p>how to perform a sum of values for multiple rows with the same name in r and render a chart in plotly.i have tried a couple of methods like aggregate and tapply, none of them seems to be working for me, could anyone tell me where I am going wrong. </p>
  
  <pre><code>library(dplyr)
      #&gt; 
      #&gt; Attaching package: 'dplyr'
      #&gt; The following objects are masked from 'package:stats':
      #&gt; 
      #&gt;     filter, lag
      #&gt; The following objects are masked from 'package:base':
      #&gt; 
      #&gt;     intersect, setdiff, setequal, union
      library(shiny)
      library(plotly)
      #&gt; Loading required package: ggplot2
      #&gt; 
      #&gt; Attaching package: 'plotly'
      #&gt; The following object is masked from 'package:ggplot2':
      #&gt; 
      #&gt;     last_plot
      #&gt; The following object is masked from 'package:stats':
      #&gt; 
      #&gt;     filter
      #&gt; The following object is masked from 'package:graphics':
      #&gt; 
      #&gt;     layout
      cdata1&lt;-data.frame(stringsAsFactors=FALSE,
                       names = c("a", "a", "a", "a", "a", "a", "a", "a", "b", "b", "b", "b",
                                 "b", "c", "c", "c", "d", "d", "d"),
                       values = c(12, 32, 43, 45, 21, 21, 21, 32, 43, 54, 65, 76, 87, 80, 78,
                                  68, 68, 67, 57)
      )
  
      ui&lt;-fluidPage(fluidRow(plotlyOutput("id1")),
                    fluidRow(plotlyOutput("id2"))
      )
  
  
  
      server&lt;-function(input,output){
  
        output$id1&lt;-renderPlotly({
  
          # a&lt;-aggregate(cdata1$X2014,by=list(cdata1$States.UTs),FUN=sum)
          # plot_ly(cdata1,x=cdata1$States.UTs,y=cdata1$X2014)
          cdata1 %&gt;%
            group_by(grp = rleid(cdata1$names)) %&gt;% 
            summarise(names = first(cdata1$names), 
                      values = sum(cdata1$values)) %&gt;%
            ungroup %&gt;%
            select(-grp)
          plot_ly(cdata1,x=cdata1$names,y=cdata1$values)
        })
  
      }
      shinyApp(ui,server)
  </code></pre>