%c% is just a short operator implementation for paste(x, y, separator="").
x %c% y
second string, which will be pasted behind the first one.
R-Core does not consider it a good idea to use + as an operator not being commutative. So we use c here.
See the discussion: https://stat.ethz.ch/pipermail/r-devel/2006-August/039013.html
Still the paste syntax seems sometimes clumsy in daily life and so %c% might spare some keys.
returns the concatenation as string.
Andri Signorell <firstname.lastname@example.org>
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"foo" %c% "bar" # works with numerics as well 345 %c% 457