plotly R: bar chart with two axes - r

Question

Is it possible to have two axes for a bar chart using plotly for R?
The code is modified from plotly bar chart example
library(plotly)
x <- c('January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December')
y1 <- c(20, 14, 25, 16, 18, 22, 19, 15, 12, 16, 14, 17)/10
y2 <- c(19, 14, 22, 14, 16, 19, 15, 14, 10, 12, 12, 16)
data <- data.frame(x, y1, y2)
#The default order will be alphabetized unless specified as below:
data$x <- factor(data$x, levels = data[["x"]])
p <- plot_ly(data, x = ~x, y = ~y1, type = 'bar', name = 'Primary Product', marker = list(color = 'rgb(49,130,189)')) %>%
add_trace(y = ~y2, name = 'Secondary Product', marker = list(color = 'rgb(204,204,204)')) %>%
layout(xaxis = list(title = "", tickangle = -45),
yaxis = list(title = ""),
margin = list(b = 100),
barmode = 'group')
p
This gives:
Values for the primary product are much smaller than secondary product - my purpose is to compare proportions by month, while still having y-axes show the actual values rather than a normalised value so it looks like this (mocked up):
I have tried plotly help to add another axis, here's the code. However, it doesn't seem to do anything, the resulting chart is the same as first one.
library(plotly)
x <- c('January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December')
y_1 <- c(20, 14, 25, 16, 18, 22, 19, 15, 12, 16, 14, 17)/10
y_2 <- c(19, 14, 22, 14, 16, 19, 15, 14, 10, 12, 12, 16)
data <- data.frame(x, y_1, y_2)
#The default order will be alphabetized unless specified as below:
data$x <- factor(data$x, levels = data[["x"]])
ay <- list(
tickfont = list(color = "red"),
overlaying = "y",
side = "right",
title = "second y axis"
)
p <- plot_ly(data, x = ~x, y = ~y_1, type = 'bar', name = 'Primary Product', marker = list(color = 'rgb(49,130,189)')) %>%
add_trace(y = ~y_2, name = 'Secondary Product', marker = list(color = 'rgb(204,204,204)'), axis = "y2") %>%
layout(yaxis2 = ay,
xaxis = list(title = "", tickangle = -45),
yaxis = list(title = ""),
margin = list(b = 100),
barmode = 'group')
p
Update 9 Aug 2018
MLavoie posted this code, which is similar to the attempt, however it gives a stacked bar chart - which is not the intended result.
data$x <- factor(data$x, levels = data[["x"]])
ay <- list(
tickfont = list(color = "red"),
overlaying = "y",
side = "right",
title = "second y axis"
)
p <- plot_ly() %>%
add_bars(data, x = ~x, y = ~y1, name = 'Primary Product', marker = list(color = 'rgb(49,130,189)')) %>%
add_bars(data, x = ~x, y = ~y2, name = 'Secondary Product', marker = list(color = 'rgb(204,204,204)'), yaxis = "y2") %>%
layout(yaxis2 = ay,
xaxis = list(title = "", tickangle = -45),
yaxis = list(title = ""),
margin = list(b = 100),
barmode = 'group')
p

Answer 1

I played with this answer and found the following derivative to give the best result.
This is the resulting plot:
library(plotly)
library(dplyr)
x <- c('January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December')
y1 <- c(20, 14, 25, 16, 18, 22, 19, 15, 12, 16, 14, 17)/10
y2 <- c(19, 14, 22, 14, 16, 19, 15, 14, 10, 12, 12, 16)
data <- data.frame(x, y1, y2)
data$x <- factor(data$x, levels = data[["x"]])
ay <- list(
overlaying = "y",
side = "right",
title = "Right Hand Axis"
)
p <- plot_ly() %>%
add_bars(data, x = ~x, y = ~y1, name = 'Primary Product (LHS)',
marker = list(color = 'rgb(49,130,189)'), offsetgroup = 1) %>%
add_bars(data, x = ~x, y = ~y2, name = 'Secondary Product (RHS)',
marker = list(color = 'rgb(204,204,204)'), yaxis = "y2", offsetgroup = 2) %>%
layout(yaxis2 = ay,
xaxis = list(title = "Time Period", tickangle = -45),
yaxis = list(title = "Left Hand Axis"),
margin = list(b = 100),
barmode = 'group',
legend = list(x = 1.1, y = 1))
p

Answer 2

I think you have a few typos, but this work.
data$x <- factor(data$x, levels = data[["x"]])
ay <- list(
tickfont = list(color = "red"),
overlaying = "y",
side = "right",
title = "second y axis"
)
p <- plot_ly() %>%
add_bars(data, x = ~x, y = ~y1, name = 'Primary Product', marker = list(color = 'rgb(49,130,189)')) %>%
add_bars(data, x = ~x, y = ~y2, name = 'Secondary Product', marker = list(color = 'rgb(204,204,204)'), yaxis = "y2") %>%
layout(yaxis2 = ay,
xaxis = list(title = "", tickangle = -45),
yaxis = list(title = ""),
margin = list(b = 100),
barmode = 'group')
p

Answer 3

A solution is to create two extra traces. Here is an example in Python :
This code is based on the code of the following separate question : Plotly Python: Align X-Axes in a grouped bar chart with multiple Y-axis

Answer 4

According to the discussion here, this should work.
x <- c('January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December')
y1 <- c(20, 14, 25, 16, 18, 22, 19, 15, 12, 16, 14, 17)/10
y2 <- c(19, 14, 22, 14, 16, 19, 15, 14, 10, 12, 12, 16)
data <- data.frame(x, y1, y2)
data$x <- factor(data$x, levels = data[["x"]])
ay <- list(
tickfont = list(color = "red"),
overlaying = "y",
side = "right",
title = "second y axis"
)
p <- plot_ly() %>%
add_bars(data, x = ~x, y = ~y1, name = 'Primary Product',
marker = list(color = 'rgb(49,130,189)'), offsetgroup = 1) %>%
add_bars(data, x = ~x, y = ~y2, name = 'Secondary Product',
marker = list(color = 'rgb(204,204,204)'), yaxis = "y2", offsetgroup = 2) %>%
layout(yaxis2 = ay,
xaxis = list(title = "", tickangle = -45),
yaxis = list(title = ""),
margin = list(b = 100),
barmode = 'group')
p
The attribute offsetgroup allows you to have more control over how the cross-trace offset and width values are computed.
Resulting plot