Dplyr join on by=(a = b), where a and b are variables containing strings?

by

You can use 

myfn <- function(xname, yname) {
    data(iris)
    inner_join(iris, iris, by=setNames(yname, xname))
}

The suggested syntax in the ?inner_join documentation of 

by = c("a"="b")   # same as by = c(a="b")

is slightly misleading because both those values aren’t proper character values. You’re actually created a named character vector. To dynamically set the values to the left of the equals sign is different from those on the right. You can use setNames() to set the names of the vector dynamically.

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