I'm trying to refactor the following:
def method_name
array = ["abcdef", "ghijkl", "mnopqr"]
collector1 = ""
collector2 = ""
collector3 = ""
array.each do |string|
collector1 += string[0..1]
collector2 += string[2..3]
collector3 += string[4..5]
end
x = collector1 + "\n" + collector2 + "\n" + collector3
# "abghmn\ncdijop\nefklqr"
end
Are there any more efficient ways to write this? Or perhaps a different enumerable that will achieve the same result?
"abghmn\ncdijop\nefklqr" is the desired output!
Thanks!!
def method_name
array = ["abcdef", "ghijkl", "mnopqr"]
array.map { |s| s.chars.each_slice(2).to_a }.transpose.map(&:join).join("\n")
end
You could write the following.
array = ["abcdef", "ghijkl", "mnopqr"]
ranges = [0..1, 2..3, 4..5]
ranges.map { |r| array.map { |s| s[r] }.join }.join('\n')
#=> "abghmn\\ncdijop\\nefklqr"
or
ranges.map { |r| array.reduce('') { |t,s| t + s[r] } }.join('\n')
#=> "abghmn\\ncdijop\\nefklqr"
I have a number of ranges that I want merge together if they overlap. The way I’m currently doing this is by using Sets.
This is working. However, when I attempt the same code with a larger ranges as follows, I get a `stack level too deep (SystemStackError).
require 'set'
ranges = [Range.new(73, 856), Range.new(82, 1145), Range.new(116, 2914), Range.new(3203, 3241)]
set = Set.new
ranges.each { |r| set << r.to_set }
set.flatten!
sets_subsets = set.divide { |i, j| (i - j).abs == 1 } # this line causes the error
puts sets_subsets
The line that is failing is taken directly from the Ruby Set Documentation.
I would appreciate it if anyone could suggest a fix or an alternative that works for the above example
EDIT
I have put the full code I’m using here:
Basically it is used to add html tags to an amino acid sequence according to some features.
require 'set'
def calculate_formatting_classes(hsps, signalp)
merged_hsps = merge_ranges(hsps)
sp = format_signalp(merged_hsps, signalp)
hsp_class = (merged_hsps - sp[1]) - sp[0]
rank_format_positions(sp, hsp_class)
end
def merge_ranges(ranges)
set = Set.new
ranges.each { |r| set << r.to_set }
set.flatten
end
def format_signalp(merged_hsps, sp)
sp_class = sp - merged_hsps
sp_hsp_class = sp & merged_hsps # overlap regions between sp & merged_hsp
[sp_class, sp_hsp_class]
end
def rank_format_positions(sp, hsp_class)
results = []
results += sets_to_hash(sp[0], 'sp')
results += sets_to_hash(sp[1], 'sphsp')
results += sets_to_hash(hsp_class, 'hsp')
results.sort_by { |s| s[:pos] }
end
def sets_to_hash(set = nil, cl)
return nil if set.nil?
hashes = []
merged_set = set.divide { |i, j| (i - j).abs == 1 }
merged_set.each do |s|
hashes << { pos: s.min.to_i - 1, insert: "<span class=#{cl}>" }
hashes << { pos: s.max.to_i - 0.1, insert: '</span>' } # for ordering
end
hashes
end
working_hsp = [Range.new(7, 136), Range.new(143, 178)]
not_working_hsp = [Range.new(73, 856), Range.new(82, 1145),
Range.new(116, 2914), Range.new(3203, 3241)]
sp = Range.new(1, 20).to_set
# working
results = calculate_formatting_classes(working_hsp, sp)
# Not Working
# results = calculate_formatting_classes(not_working_hsp, sp)
puts results
Here is one way to do this:
ranges = [Range.new(73, 856), Range.new(82, 1145),
Range.new(116, 2914), Range.new(3203, 3241)]
ranges.size.times do
ranges = ranges.sort_by(&:begin)
t = ranges.each_cons(2).to_a
t.each do |r1, r2|
if (r2.cover? r1.begin) || (r2.cover? r1.end) ||
(r1.cover? r2.begin) || (r1.cover? r2.end)
ranges << Range.new([r1.begin, r2.begin].min, [r1.end, r2.end].max)
ranges.delete(r1)
ranges.delete(r2)
t.delete [r1,r2]
end
end
end
p ranges
#=> [73..2914, 3203..3241]
The other answers aren't bad, but I prefer a simple recursive approach:
def merge_ranges(*ranges)
range, *rest = ranges
return if range.nil?
# Find the index of the first range in `rest` that overlaps this one
other_idx = rest.find_index do |other|
range.cover?(other.begin) || other.cover?(range.begin)
end
if other_idx
# An overlapping range was found; remove it from `rest` and merge
# it with this one
other = rest.slice!(other_idx)
merged = ([range.begin, other.begin].min)..([range.end, other.end].max)
# Try again with the merged range and the remaining `rest`
merge_ranges(merged, *rest)
else
# No overlapping range was found; move on
[ range, *merge_ranges(*rest) ]
end
end
Note: This code assumes each range is ascending (e.g. 10..5 will break it).
Usage:
ranges = [ 73..856, 82..1145, 116..2914, 3203..3241 ]
p merge_ranges(*ranges)
# => [73..2914, 3203..3241]
ranges = [ 0..10, 5..20, 30..50, 45..80, 50..90, 100..101, 101..200 ]
p merge_ranges(*ranges)
# => [0..20, 30..90, 100..200]
I believe your resulting set has too many items (2881) to be used with divide, which if I understood correctly, would require 2881^2881 iterations, which is such a big number (8,7927981983090337174360463368808e+9966) that running it would take nearly forever even if you didn't get stack level too deep error.
Without using sets, you can use this code to merge the ranges:
module RangeMerger
def merge(range_b)
if cover?(range_b.first) && cover?(range_b.last)
self
elsif cover?(range_b.first)
self.class.new(first, range_b.last)
elsif cover?(range_b.last)
self.class.new(range_b.first, last)
else
nil # Unmergable
end
end
end
module ArrayRangePusher
def <<(item)
if item.kind_of?(Range)
item.extend RangeMerger
each_with_index do |own_item, idx|
own_item.extend RangeMerger
if new_range = own_item.merge(item)
self[idx] = new_range
return self
end
end
end
super
end
end
ranges = [Range.new(73, 856), Range.new(82, 1145), Range.new(116, 2914), Range.new(3203, 3241)]
new_ranges = Array.new
new_ranges.extend ArrayRangePusher
ranges.each do |range|
new_ranges << range
end
puts ranges.inspect
puts new_ranges.inspect
This will output:
[73..856, 82..1145, 116..2914, 3203..3241]
[73..2914, 3203..3241]
which I believe is the intended output for your original problem. It's a bit ugly, but I'm a bit rusty at the moment.
Edit: I don't think this has anything to do with your original problem before the edits which was about merging ranges.
str = 'put returns between paragraph put returns between paragraph put returns between paragraph'
def word_count(string)
resut= []
return result = string.split.inject(Hash.new(0)) { |h,v| h[v] += 1; h }
end
def parse_word(word)
word.gsub!(/[^a-zA-Z0-9]/, " ")
word.downcase!
#yoo= word
end
result =word_count(str)
print result, "\n\n"
res2 = result.select { |pair| pair[1] > 1 } `#Error coming`
I am getting OutPut
**
OutPut
**
{"put"=>3, "returns"=>3, "between"=>3, "paragraph"=>3}
I need OutPut Like this
**
OutPut
**
{"put"=>3, "returns"=>3, "between"=>3, "paragraph"=>3}
and
put: 3
returns: 3
between: 3
but the main problem is that he gave us the code to do that but i cant able to understand it
I am not getting this what this code will do can anyone help me ...And modify it so it can work
The following processes the first paragraph of put returns ... Note that ss is an array of those words that occur at least twice in this paragraph.
nect = ss.select { |p| p[1] > 1 }
nect .sort.each do |key, count|
puts "#{key}: #{count}"
end
module WordCount
def self.word_count(s)
count_frequency(words_from_string(s))
end
def self.word_count_from_file(filename)
s = File.open(filename) { |file| file.read }
word_count(s)
end
def self.words_from_string(s)
s.downcase.scan(/[\w']+/)
end
def self.count_frequency(words)
counts = Hash.new(0)
for word in words
counts[word] += 1
end
# counts.to_a.sort {|a,b| b[1] <=> a[1]}
# sort by decreasing count, then lexicographically
counts.to_a.sort do |a,b|
[b[1],a[0]] <=> [a[1],b[0]]
end
end
end
def word_count(s)
WordCount.word_count(s)
end
I have the following implementation of a linked list in Ruby:
class Node
attr_accessor :data, :next
def initialize(data = nil)
#data = data
#next = nil
end
end
class LinkedList
def initialize(items)
#head = Node.new(items.shift)
items.inject(#head) { |last, data| #tail = last.next = Node.new(data) }
end
def iterate
return nil if #head.nil?
entry = #head
until entry.nil?
yield entry
entry = entry.next
end
end
def equal?(other_list)
#How do I check if all the data for all the elements in one list are the same in the other one?
end
end
I have tried using the .iterate like this:
def equals?(other_list)
other_list.iterate do |ol|
self.iterate do |sl|
if ol.data != sl.data
return false
end
end
end
return true
end
But this is doing a nested approach. I fail to see how to do it.
You can't do it easily with the methods you have defined currently, as there is no way to access a single next element. Also, it would be extremely useful if you implemented each instead of iterate, which then gives you the whole power of the Enumerable mixin.
class LinkedList
include Enumerable # THIS allows you to use `zip` :)
class Node # THIS because you didn't give us your Node
attr_accessor :next, :value
def initialize(value)
#value = value
#next = nil
end
end
def initialize(items)
#head = Node.new(items.shift)
items.inject(#head) { |last, data| #tail = last.next = Node.new(data) }
end
def each
return enum_for(__method__) unless block_given? # THIS allows block or blockless calls
return if #head.nil?
entry = #head
until entry.nil?
yield entry.value # THIS yields node values instead of nodes
entry = entry.next
end
end
def ==(other_list)
# and finally THIS - get pairs from self and other, and make sure all are equal
zip(other_list).all? { |a, b| a == b }
end
end
a = LinkedList.new([1, 2, 3])
b = LinkedList.new([1, 2, 3])
c = LinkedList.new([1, 2])
puts a == b # => true
puts a == c # => false
EDIT: I missed this on the first run through: equal? is supposed to be referential identity, i.e. two variables are equal? if they contain the reference to the same object. You should not redefine that method, even though it is possible. Rather, == is the general common-language meaning of "equal" as in "having the same value", so I changed it to that.
I think there is something wrong with your initialize method in LinkedList, regardless could this be what you need
...
def equal?(other_list)
other_index = 0
cur_index = 0
hash = Hash.new
other_list.iterate do |ol|
hash[ol.data.data] = other_index
other_index += 1
end
self.iterate do |node|
return false if hash[node.data.data] != cur_index
return false if !hash.has_key?(node.data.data)
cur_index += 1
end
return true
end
...
Assuming this is how you use your code
a = Node.new(1)
b = Node.new(2)
c = Node.new(3)
listA = [a,b,c]
aa = Node.new(1)
bb = Node.new(2)
cc = Node.new(3)
listB = [aa,bb,cc]
linkA = LinkedList.new(listA)
linkB = LinkedList.new(listB)
puts linkA.equal?(linkB)
I'm new to ruby i would like to know how can i split element containing special character.
I have the following array :
my_array = ["sh.please-word", ".things-to-do" , "#cool-stuff", "span.please-word-not"]
my_array.slice!(0..1)
puts my_array
=>#cool-stuff
=>span.please-word
i want it to split array elements that doesn't start with either a dot(.) or a (#) and return the list like this:
.please-word
.things-to-do
#cool_stuff
.please-word-not
i tried to use the slice method for a string which works perfectly, but when i try with the array element it doesn't work.
this is what i have done so far.
list_of_selectors = []
file = File.open("my.txt")
file.each_line do |line|
list_of_selectors << line.split(' {')[0] if line.start_with? '.' or line.start_with? '#'
end
while line = file.gets
puts line
end
i = 0
while i < list_of_selectors.length
puts "#{list_of_selectors[i]}"
i += 1
end
list = []
list_of_selectors.each { |x|
list.push(x.to_s.split(' '))
}
list_of_selectors = list
puts list_of_selectors
list_of_selectors.map! { |e| e[/[.#].*/]}
puts list_of_selectors
result_array = my_array.map { |x| x[/[.#].*/] }
# => [".please-word", ".things-to-do", "#cool-stuff", ".please-word-not"]
The above uses a regular expression to extract the text, beginning with either a dot(.) or a hashtag (#), and return it in the resulting array.