gabrielgiordano
Version comparison with built-in comparison keywords "3.3.15.1" > "3.3.15.0"
Hello community!
I’ve been comparing some version string binaries with the built-in comparison keywords, and the results seems about right.
I assume that the kind of data type Elixir is comparing in those cases are bitstrings, right?
Do you think this is a reliable way to compare that kind of version pattern, or am I missing something?
iex(1)> "3.0.0.0.0" > "3.3.15.0"
false
iex(2)> "3.0.0.0.0" > "3.3.15.0"
false
iex(3)> "3.3.15.0" > "3.3.15.0"
false
iex(4)> "3.3.15.1" > "3.3.15.0"
true
iex(5)> "3.3.15.1" > "3.3.15.0"
true
iex(6)> "3.3.14.9" > "3.3.15.0"
false
iex(7)> "3.3.0.0.0.0" > "3.3.15.0"
false
iex(8)> "3.3.0.0.0.0" > "3.4"
false
By the way, I’ve checked the Version module, but the version pattern doesn’t entirely comply with SemVer, so if we use it, we’ll need to handle our version before 
Marked As Solved
LostKobrakai
If this is only numbers (no prereleases) then you use lists of numbers to compare. Their sort order should match what I imagine you want the versions to sort by:
[3, 14] > [3, 13, 9]
true
Also Liked
APB9785
def string_to_version(s) do
s
|> String.split(".")
|> Enum.map(&String.to_integer/1)
end
This would give you integer lists like in LostKobraKai’s post
APB9785
For versions, I would expect version 2 to be lower than version 15 
hauleth
How does Version do not comply with SemVer? Especially that your versions mentioned there aren’t really SemVer compatible, as have more segments than 3 (major, minor, and patch).
If you want to compare them:
def parse_ver(str) do
str
|> String.split(".")
|> Enum.map(&String.to_integer/1)
end
def compare([a | as], [b | bs]) when a == b, do: compare(as, bs)
def compare([], []), do: {:ok, :equal}
def compare([a | _], [b | _]) when a > b, do: {:ok, :greater}
def compare([a | _], [b | _]) when a < b, do: {:ok, :lesser}
def compare(_, _), do: {:error, :incomparable}
Popular in Questions
Other popular topics
Latest on Elixir Forum
Sponsor Spotlight
Supporting innovation across the BEAM ecosystem.
Categories:
Sub Categories:
Forums
Our Sponsors
Build Elixir applications with speed and confidence.
Supporting innovation across the BEAM ecosystem.
We build reliable cloud platforms for business-critical systems.
Catch errors, track performance, monitor hosts and more.
Practical resources that improve the lives of professional developers.
Develop your skills with books, videos, and courses.
Enabling companies to succeed by building software people love.
Courses that'll move you from confusion to "Aha, now I get it!"