elixirdev
How can I get immediate greater and lesser value of a number
value = 7
jobs = [1, 4, 9, 3, 8, 6, 2]
output should be 6,8
i have large and too many lists. please suggest me optimised solutions.
Marked As Solved
mudasobwa
jobs = [1, 4, 9, 3, 8, 6, 2]
num = 7
Enum.reduce(jobs, {nil, nil}, fn
e, {nil, max} when e < num -> {e, max}
e, {min, nil} when e > num -> {min, e}
e, {min, max} when e > min and e < num -> {e, max}
e, {min, max} when e < max and e > num -> {min, e}
_, min_max -> min_max
end)
The idea is you walk through the list narrowing down the difference. Maybe this looks shorter:
Enum.reduce(jobs, {nil, nil}, fn
e, {min, max} when (is_nil(min) or e > min) and e < num -> {e, max}
e, {min, max} when (is_nil(max) or e < max) and e > num -> {min, e}
_, min_max -> min_max
end)
Also Liked
NobbZ
So for any given n, do you always want to check if n-1 and n+1 are in the list, or do you search those x for that holds that there is no y greather than x and lesser than n (and the other way round for the other side)?
edit
Perhaps my last sentence could be better phrased as “…or do you want to search for the greatest number smaller than n as well as the smallest number greater than n?”
another edit
If it is the first, I’d roughly do
def search(n, list) do
Enum.filter(list, & &1 in [n-1, n+1])
endmudasobwa
Yeah, I know. I would even go with my first snippet because I value clarity way more than brevity.
Popular in Questions
Other popular topics
Latest on Elixir Forum
Sponsor Spotlight
Catch errors, track performance, monitor hosts and more.
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!"