Cyclomatic Complexity of R Code
Cyclomatic complexity is a software metric (measurement), used to indicate the complexity of a program. It is a quantitative measure of the number of linearly independent paths through a program’s source code. It was developed by Thomas J. McCabe, Sr. in 1976.
devtools::install_github("Gaborcsardi/cyclocomp")library(cyclocomp)cyclocomp takes quoted R expressions or function objects, and returns
a single integer, the cyclomatic complexity of the expression or
function.
cyclocomp(quote( if (condition) "foo" else "bar" ))#> [1] 2
cyclocomp(quote( while (condition) { loop } ))#> [1] 3
cyclocomp(
function(arg) { calulate(this); and(that) }
)#> [1] 1
cyclocomp(ls)#> [1] 10
cyclocomp(cyclocomp)#> [1] 1
Some more examples for the R control structures. A simple if first:
cyclocomp(quote({
if (condition) this
}))#> [1] 2
An if with an else branch:
cyclocomp(quote({
if (condition) this else that
}))#> [1] 2
Loops:
cyclocomp(quote({
for (var in seq) expr
}))#> [1] 3
cyclocomp(quote({
while (cond) expr
}))#> [1] 3
cyclocomp(quote({
repeat expr
}))#> [1] 2
break and next statements add to the complexity:
cyclocomp(quote({
for (var in seq) {
this
break
that
}
}))#> [1] 4
cyclocomp(quote({
for (var in seq) {
this
next
that
}
}))#> [1] 4
Multiple (explicit or implicit) return calls also add to the
complexity:
f <- function(arg) {
if (arg) {
return("this")
} else {
return("that")
}
"Otherwise return me"
}
cyclocomp(f)#> [1] 4
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