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str.count("\n") is 1.3-170 times faster than str.lines.count or str.each_line.count depending on the string size #220
Description
str.count("\n") is 1.3-170 times faster than str.lines.count or str.each_line.count (ref: https://serpapi.com/blog/lines-count-failed-deployments/). The speed difference grows with the lines count.
$ ruby tmp/string_count_benchmark.rb
Warming up --------------------------------------
String#count('\n') 86.000 i/100ms
String#lines.size 1.000 i/100ms
String#lines.count 1.000 i/100ms
String#each_line.count
1.000 i/100ms
Calculating -------------------------------------
String#count('\n') 771.031 (± 6.6%) i/s - 3.870k in 5.041849s
String#lines.size 4.785 (± 0.0%) i/s - 24.000 in 5.037242s
String#lines.count 4.513 (± 0.0%) i/s - 23.000 in 5.112095s
String#each_line.count
4.763 (± 0.0%) i/s - 24.000 in 5.075882s
Comparison:
String#count('\n'): 771.0 i/s
String#lines.size: 4.8 i/s - 161.12x (± 0.00) slower
String#each_line.count: 4.8 i/s - 161.87x (± 0.00) slower
String#lines.count: 4.5 i/s - 170.86x (± 0.00) slowerBenchmark code:
require "benchmark/ips"
HTML = "\nruby\n" * 1024 * 1024
def fastest
HTML.count("\n")
end
def faster
HTML.each_line.count
end
def fast
HTML.lines.length
end
def slow
HTML.lines.size
end
Benchmark.ips do |x|
x.report("String#count('\\n')") { fastest }
x.report("String#lines.size") { faster }
x.report("String#lines.count") { fast }
x.report("String#each_line.count") { slow }
x.compare!
endI'd like to add this benchmark to fast-ruby. Wdyt?
Based on our updates to the @guilhermesimoes' very helpful gist: https://gist.github.com/guilhermesimoes/d69e547884e556c3dc95?permalink_comment_id=4687645#gistcomment-4687645
Activity
ilyazub commentedon Oct 26, 2023
@JuanVqz @etagwerker what do you think about a benchmark for
String#countvsString#lines.countvsString#each_line.count?JuanVqz commentedon Oct 26, 2023
This seems a Rails related benchmark, I wonder if we are adding framework-related benchmarks
ilyazub commentedon Oct 27, 2023
It doesn't depend on Rails (ruby/ruby#4001 (comment)). I updated the benchmark code to work with the plain Ruby.
ilyazub commentedon Oct 31, 2023
@JuanVqz I updated the benchmark code above to work with the plain Ruby.
What do you think?
ixti commentedon Nov 21, 2023
IMHO using
$/is bad - it's less obvious than"\n". More than that,$/can be redefined, so the code may become broken.[-]`str.count($/)` is 1.3x faster than `str.lines.count` or `str.each_line.count`[/-][+]`str.count("\n")` is 1.3x faster than `str.lines.count` or `str.each_line.count`[/+]ilyazub commentedon Nov 21, 2023
@ixti Sounds good. The performance difference is in the
String#countvs other methods.$/vs\ndid't impact performance here.[-]`str.count("\n")` is 1.3x faster than `str.lines.count` or `str.each_line.count`[/-][+]`str.count("\n")` is 1.3-170 times faster than `str.lines.count` or `str.each_line.count` depending on the string size[/+]