Count the number of instances of a string of text in an entire dataframe

I have a dataframe and I want to count the number of instances of a particular string of text.

For example in the below dataframe:

library(tidyverse)

df<-iris%>%
    select(Species)%>%
    distinct()%>%
    mutate(Species2=Species)%>%
    mutate(Species3=Species)

I want to count the number of times "setosa" occurs

Using length(grep("setosa", df$Species)) I can get the counts of setosa in a specific column but
how can I do this to the whole dataframe?

I tried length(grep("setosa", df)) which comes back as zero

Any suggestions?

>Solution :

Assuming you just want total count, rather than count by column, your code works if you convert the dataframe to a matrix first:

length(grep("setosa", as.matrix(df)))

which returns 3.

Note: unlike unlist() this also works when columns have different classes:

length(grep("OJ", as.matrix(ToothGrowth)))