I was given a file of size 46KB full of names (around ~5000), in the format as shown below:
"MARY","PATRICIA","LINDA","BARBARA","ELIZABETH"..."DARRELL","ALONSO"
I wonder if my code below is optimal in doing what I want, which is to translate this txt file into an array of names.
array = []
File.readlines('names.txt').each do |l|
array << l.delete("\"").split(",")
end
array.flatten
Yes it is, it takes 0.372798 seconds to run on my computer for a 50 MB file, for a 46KB file this runs in the blink of an eye.
Anyway as this is Codereview I suggest an equally fast but higher level version of your code:
def get_names(filename)
File.read(filename).tr('"', '').split(',')
end
def rand_string(len) (0...len).map { (65 + rand(26)).chr }.join end def gen_file names = (1..10000).map{|x| '"'+rand_string(x)+'"'}.join(',') File.write("names.txt", names) end
\$\endgroup\$
You can also do
def get_names(filename)
File.read(filename).scan(/[a-z\s]+/i)
end
In this case, the scan looks for contiguous runs of letters and spaces, and captures those. So instead of removing quotes and splitting on commas, we're capturing stuff that isn't a comma or quote.
Don't know if it's faster, though (haven't tried it). Just presenting an alternative.
My first concern is correctness, not speed. The input string is quoted for a reason, presumably to allow for the possibility of a literal comma within one of the names, e.g. "MARY, QUEEN OF SCOTS". Granted, it would be weird for that situation to actually happen, but I think it's poor practice to disregard the quotes completely.
Therefore, I would go with @Snowbody's approach. I would refine it a bit by stripping the double-quotes from just the first and last items of each line, based on the reasoning that modifying short strings should be faster than copying the entire line.
File.readlines('names.txt').flat_map do |line|
line_names = line.split('","')
line_names[0].delete!('"')
line_names[-1].chomp!(',')
line_names[-1].chomp!('"')
line_names
end
This may or may not be faster:
def get_names(filename)
('",' + File.read(filename) + ',"').split('","')
end
due to the initial insert possibly reallocating.
