Is there a way to remove a specific instance of an item from a string? For example, if I have the string:
"kiwi, durian, and, starfruit"
how can I remove the final comma only? I need a solution that will remove the last comma from the string no matter how many items the string contains.
Couldn't find anything at all on this by Googling around (at least not for Ruby without Rails. If you're using Rails, it's easy--just use the array.to_sentence method.)
You could reverse the string, sub a comma for "", and reverse it again.
But rindexis nice too:
str = "kiwi, durian, and, starfruit"
str.slice!(str.rindex(","))
p str # => "kiwi, durian, and starfruit"
[]= is better.
sub and gsub.
"," for me. The only answer that worked was the one I marked as correct. Thanks for your help!str.You could use sub like this:
"kiwi, durian, and, starfruit".sub(/,([^,]*)\z/, '\1')
#=> "kiwi, durian, and starfruit"
$1 doesn't do here what you think it does. You want '\1'. Also what about non-word chars?gsub is slower than sub.How about:
"kiwi, durian, and, starfruit".sub /(.*),/, '\1'
#=> "kiwi, durian, and starfruit"
it works because the .* is greedy
sub is faster than gsub, relying on a regex is costly unless the regex is anchored. And, even then, they tend to lose-out to using the built-in methods.String to array split on the commas, then re join all but the last items with a comma and add the final part of the array back on.
string = "kiwi, durian, and, starfruit"
array = string.split","
pre = array.slice(0,array.length - 1).join","
post = array[array.length - 1]
output = pre + post
p = output
There being five answers over nine hours, all that's left are crumbs. Here's one:
str = "kiwi, durian, and, starfruit"
str[str[/.*,/].size-1] = ''
str #=> "kiwi, durian, and tarfruit"
If the string always includes "and" you could use gsub.
new_string = "kiwi, durian, and, starfruit".gsub("and,", "and")
Otherwise you could write a function like this:
def strip_last_comma string
spt_str = string.split(",")
string = spt_str[0..spt_str.size-2].join(",") + spt_str.last
end
gsub will always run slower than using sub when you're only replacing one thing.sub only tries to replace once, where gsub will try at least once more and if the string being searched is really long and the first hit was at the start, the resulting second search will waste CPU.