Fastest Way to Parse this String in Ruby

Question

I am currently looking for the fastest way to parse a string in Ruby. The string has the format:

"#{String1}>#{String2}(#{Integer})", for example "Hello>World(25)"

and I am looking to retrieve the values of String1, String2, and Integer out of it. My current way of doing it is just

s1 = "Hello"
s2 = "World"
i = 25
str = "#{s1}>#{s2}(#{i})"
str = str.split('>')
newStr = str[1].split('(')
str[1] = newStr[0]
str[2] = newStr[1].chomp(')').to_i
print(str)   # => ["Hello", "World", 25]`

I am looking for any way faster than this to speed up my program. Thanks.

Ashik Salman · Accepted Answer · 2018-03-14 07:03:31Z

2

String partition method is even faster than split method.

str = "Hello>World(25)"

a, _, b = str.partition('>')
b, _, c = b.partition('(')
c = c.to_i

puts a, b, c

answered Mar 14, 2018 at 7:03

Ashik Salman

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1 Comment

engineersmnky Over a year ago

This is indeed the fastest way

Simple Lime · Accepted Answer · 2018-03-14 03:37:02Z

1

If you want speed over readability, you're probably really close to the fastest you're going to get. I was able to shave a little bit of time off of your implementation by passing the optional limit parameter to split and omitting the chomp(')') which isn't needed:

  # Way #1
  str = str.split('>', 2)
  newStr = str[1].split('(', 2)
  str[1] = newStr[0]
  str[2] = newStr[1].to_i

or, at right about the same speed (it's faster in some runs, slower in others):

  # Way #2
  str = str.split(/[>(]/, 3)
  str[2] = str[2].to_i

answered Mar 14, 2018 at 3:37

Simple Lime

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1 Comment

zeus54 Over a year ago

Way #1 worked perfectly, chopped off ~5ms off of my average runtime. Way #2 added ~15ms to it however. Either way, way #1 answered my question perfectly. Thanks.

Roma149 · Accepted Answer · 2018-03-13 23:36:01Z

1

You could use regex capture groups to obtain these values:

str = "Hello>World(25)"
s1, s2, i = str.match(/(\w+)>(\w+)\((\d+)\)/i).captures

answered Mar 13, 2018 at 23:36

Roma149

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zeus54 Over a year ago

I just tested this method, and while it is much easier to read, it slows down the execution of my program by ~12%

Zoran · Accepted Answer · 2018-03-13 23:30:48Z

0

You can use regex inside your #split method to achieve the same result:

string = "Hello>World(25)"
result = string.split(/[>,()]/)
result[-1] = result[-1].to_i

result
# => ["Hello", "World", 25]

Hope this helps!

edited Mar 13, 2018 at 23:30

answered Mar 13, 2018 at 23:19

Zoran

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1 Comment

zeus54 Over a year ago

I just tested this method, and while it is much easier to read, it slows down the execution of my program by ~9%

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