R plotly barplot, sort by value

Question

I have a barplot with categories on X axis and counts on Y. Is there a way to sort the bars in descending order on values of Y? this is the sample code ``` Animals <- c("giraffes", "orangutans", "monkeys") Count <- c(20, 14, 23) data <- data.frame(Animals, Count) data <- arrange(data,desc(Count)) plot_ly(data, x = ~Animals, y = ~Count, type = 'bar', name = 'SF Zoo') ``` Despite of arranging the data by count before the plot, I still get bars sorted alphabetically by animal names. thanks, Manoj

Accepted Answer

A couple things:

- Look at `str(data)`, your `Animals` character vector is coerced to a factor unless you specify `stringsAsFactors = FALSE` in your call to `data.frame`. The levels of this factor are alphabetic by default.

- Even if `Animals` is made to be a character vector in `data`, `plot_ly` doesn't know what to do with character variables and so will coerce them to factors.

You need to set factor level order to get the descending order you are looking for.

```
Animals <- c("giraffes", "orangutans", "monkeys")
Count <- c(20, 14, 23)
data <- data.frame(Animals, Count, stringsAsFactors = FALSE)
data$Animals <- factor(data$Animals, levels = unique(data$Animals)[order(data$Count, decreasing = TRUE)])
plot_ly(data, x = ~Animals, y = ~Count, type = "bar", name = 'SF Zoo')
```

R plotly barplot, sort by value

Solution

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