Understanding `sep` and `collapse` in R using `paste()

pasteUsingSepAndCollapseInR.R

# The difference between the `sep` and `collapse` arguments
# in paste can be thought of like this:
# 
# paste can accept multiple *vectors* as input, and will
# concatenate the ith entries of each vector pairwise 
# (or tuplewise), if it can.
# 
# When you pass paste multiple vectors, sep defines what
# separates the entries in those tuple-wise concatenations.
# 
# When you pass paste a *collapse* value, it will return
# any concatenated pairs as part of a single length-1 
# character vector, with the tuples separated by 
# the string you passed to `collapse`

x <- c("a", "b", "c", "d")
y <- c("w", "x", "y", "z")

# The statement below will return
# "a%%w" "b%%x" "c%%y" "d%%z"
# A tuple of character concatenations, where within
# each tuple, the concatenations are separated by the sep
# argument
paste(x, y, sep="%%")

# The statement below this will return
# "a%%w,b%%x,c%%y,d%%z"
# It's the same tuple-wise concatenation as above,
# but this time there's the additional step of reducing
# the output to a vector of length one and shoving the 
# collapse value between the entries. Note how in the output
# there are four instances of "%%", but only three of "," 
paste(x, y, sep="%%", collapse=",")

# To confirm our conjecture, we can swap the sep and 
# collapse arguments. The statement below will return
# "a,w%%b,x%%c,y%%d,z"
paste(x, y, sep=",", collapse="%%")

Thanks

This bugged me for quite awhile. Thanks for the very good explanation in your comments.

Thanks

Clean example. Thanks

thanks!much understandable

Thanks a lot, after read severals time, finally I understood.

that's really clear! thx!

nice and clear. thanks.

That's well put!

thanks

while(1){
print("Thanks")
}

Thank you!

Great work, thanks,

This is great and works for me, tho for others I think explaining %% when you introduce that notation would be useful

Thank you!

Much obliged

thanks

Awesome! Example at the end seals it. thanks!

Wow.... Thanks !!!

Thank you!

Thank you!

Thank you! very informative!

Nice explanation, to add further, try running this

length(paste(x,y,sep = "%%",collapse=","))

Output: 1 (Returns a single character)
and this

length(paste(x,y,sep = "%%"))

Output: 4 (Returns character with length 4)

@Anant-mishra1729, you may need to edit the second code without the "collapse" to give the expected result, for the sake of new R users length(paste(x,y,sep = "%%"))

aah thanks