I'm trying to convert an array into a hash by using some matching. Before converting the array into a hash, I want to merge the values like this
"Desc,X1XXSC,C,CCCC4524,xxxs,xswd"
and create a hash from it. The rule is that, first value of the array is the key in Hash, in array there are repeating keys, for those keys I need to merge values and place it under one key. "Desc:" are keys. My program looks like this.
p 'test sample application'
str = "Desc:X1:C:CCCC:Desc:XXSC:xxxs:xswd:C:4524"
arr = Array.new
arr = str.split(":")
p arr
test_hash = Hash[*arr]
p test_hash
I could not find a way to figure it out. If any one can guide me, It will be thankful.
Functional approach with Facets:
require 'facets'
str.split(":").each_slice(2).map_by { |k, v| [k, v] }.mash { |k, vs| [k, vs.join] }
#=> {"Desc"=>"X1XXSC", "C"=>"CCCC4524", "xxxs"=>"xswd"}
Not that you cannot do it without Facets, but it's longer because of some basic abstractions missing in the core:
Hash[str.split(":").each_slice(2).group_by(&:first).map { |k, gs| [k, gs.map(&:last).join] }]
#=> {"Desc"=>"X1XXSC", "C"=>"CCCC4524", "xxxs"=>"xswd"}
A small variation on #Sergio Tulentsev's solution:
str = "Desc:X1:C:CCCC:Desc:XXSC:xxxs:xswd:C:4524"
str.split(':').each_slice(2).each_with_object(Hash.new{""}){|(k,v),h| h[k] += v}
# => {"Desc"=>"X1XXSC", "C"=>"CCCC4524", "xxxs"=>"xswd"}
str.split(':') results in an array; there is no need for initializing with arr = Array.new
each_slice(2) feeds the elements of this array two by two to a block or to the method following it, like in this case.
each_with_object takes those two elements (as an array) and passes them on to a block, together with an object, specified by:
(Hash.new{""}) This object is an empty Hash with special behaviour: when a key is not found then it will respond with a value of "" (instead of the usual nil).
{|(k,v),h| h[k] += v} This is the block of code which does all the work. It takes the array with the two elements and deconstructs it into two strings, assigned to k and v; the special hash is assigned to h. h[k] asks the hash for the value of key "Desc". It responds with "", to which "X1" is added. This is repeated until all elements are processed.
I believe you're looking for each_slice and each_with_object here
str = "Desc:X1:C:CCCC:Desc:XXSC:xxxs:xswd:C:4524"
hash = str.split(':').each_slice(2).each_with_object({}) do |(key, value), memo|
memo[key] ||= ''
memo[key] += value
end
hash # => {"Desc"=>"X1XXSC", "C"=>"CCCC4524", "xxxs"=>"xswd"}
Enumerable#slice_before is a good way to go.
str = "Desc:X1:C:CCCC:Desc:XXSC:xxxs:xswd:C:4524"
a = ["Desc","C","xxxs"] # collect the keys in a separate collection.
str.split(":").slice_before(""){|i| a.include? i}
# => [["Desc", "X1"], ["C", "CCCC"], ["Desc", "XXSC"], ["xxxs", "xswd"], ["C", "4524"]]
hsh = str.split(":").slice_before(""){|i| a.include? i}.each_with_object(Hash.new("")) do |i,h|
h[i[0]] += i[1]
end
hsh
# => {"Desc"=>"X1XXSC", "C"=>"CCCC4524", "xxxs"=>"xswd"}
Related
I have read the xls and have formed these three hashes
hash1=[{'name'=>'Firstname',
'Locator'=>'id=xxx',
'Action'=>'TypeAndWait'},
{'name'=>'Password',
'Locator'=>'id=yyy',
'Action'=>'TypeAndTab'}]
Second Hash
hash2=[{'Test Name'=>'Example',
'TestNumber'=>'Test1'},
{'Test Name'=>'Example',
'TestNumber'=>'Test2'}]
My Thrid Hash
hash3=[{'name'=>'Firstname',
'Test1'=>'four',
'Test2'=>'Five',
'Test3'=>'Six'},
{'name'=>'Password',
'Test1'=>'Vicky',
'Test2'=>'Sujin',
'Test3'=>'Sivaram'}]
Now my resultant hash is
result={"Example"=>
{"Test1"=>
{'Firstname'=>
["id=xxx","four", "TypeAndWait"],
'Password'=>
["id=yyy","Vicky", "TypeAndTab"]},
"Test2"=>
{'Firstname'=>
["id=xxx","Five", "TypeAndWait"],
'Password'=>
["id=yyy","Sujin", "TypeAndTab"]}}}
I have gotten this result, but I had to write 60 lines of code in my program, but I don't think I have to write such a long program when I use Ruby, I strongly believe some easy way to achieve this. Can some one help me?
The second hash determines the which testcase has to be read, for an example, test3 is not present in the second testcase so resultant hash doesn't have test3.
We are given three arrays, which I've renamed arr1, arr2 and arr3. (hash1, hash2 and hash3 are not especially good names for arrays. :-))
arr1 = [{'name'=>'Firstname', 'Locator'=>'id=xxx', 'Action'=>'TypeAndWait'},
{'name'=>'Password', 'Locator'=>'id=yyy', 'Action'=>'TypeAndTab'}]
arr2 = [{'Test Name'=>'Example', 'TestNumber'=>'Test1'},
{'Test Name'=>'Example', 'TestNumber'=>'Test2'}]
arr3=[{'name'=>'Firstname', 'Test1'=>'four', 'Test2'=>'Five', 'Test3'=>'Six'},
{'name'=>'Password', 'Test1'=>'Vicky', 'Test2'=>'Sujin', 'Test3'=>'Sivaram'}]
The drivers are the values "Test1" and "Test2" in the hashes that are elements of arr2. Nothing else in that array is needed, so let's extract those values (of which there could be any number, but here there are just two).
a2 = arr2.map { |h| h['TestNumber'] }
#=> ["Test1", "Test2"]
Next we need to rearrange the information in arr3 by creating a hash whose keys are the elements of a2.
h3 = a2.each_with_object({}) { |test,h|
h[test] = arr3.each_with_object({}) { |f,g| g[f['name']] = f[test] } }
#=> {"Test1"=>{"Firstname"=>"four", "Password"=>"Vicky"},
# "Test2"=>{"Firstname"=>"Five", "Password"=>"Sujin"}}
Next we need to rearrange the content of arr1 by creating a hash whose keys match the keys of values of h3.
h1 = arr1.each_with_object({}) { |g,h| h[g['name']] = g.reject { |k,_| k == 'name' } }
#=> {"Firstname"=>{"Locator"=>"id=xxx", "Action"=>"TypeAndWait"},
# "Password"=>{"Locator"=>"id=yyy", "Action"=>"TypeAndTab"}}
It is now a simple matter of extracting information from these three objects.
{ 'Example'=>
a2.each_with_object({}) do |test,h|
h[test] = h3[test].each_with_object({}) do |(k,v),g|
f = h1[k]
g[k] = [f['Locator'], v, f['Action']]
end
end
}
#=> {"Example"=>
# {"Test1"=>{"Firstname"=>["id=xxx", "four", "TypeAndWait"],
# "Password"=>["id=yyy", "Vicky", "TypeAndTab"]},
# "Test2"=>{"Firstname"=>["id=xxx", "Five", "TypeAndWait"],
# "Password"=>["id=yyy", "Sujin", "TypeAndTab"]}}}
What do you call hash{1-2-3} are arrays in the first place. Also, I am pretty sure you have mistyped hash1#Locator and/or hash3#name. The code below works for this exact data, but it should not be hard to update it to reflect any changes.
hash2.
map(&:values).
group_by(&:shift).
map do |k, v|
[k, v.flatten.map do |k, v|
[k, hash3.map do |h3|
# lookup a hash from hash1
h1 = hash1.find do |h1|
h3['name'].start_with?(h1['Locator'])
end
# can it be nil btw?
[
h1['name'],
[
h3['name'][/.*(?=-id)/],
h3[k],
h1['Action']
]
]
end.to_h]
end.to_h]
end.to_h
I'm trying to increment all values of a hash by a given amount and return the hash. I am expecting:
add_to_value({"a" => 1, "c" => 2,"b"=> 3}, 1)
# => {"a" => 2, "c" => 3,"b"=> 4}
I'm thinking:
def add_to_value(hash, x)
hash.each {|key,value| value + x}
end
This returns:
{"a"=>1, "b"=>3, "c"=>2}
Why is hash sorted alphabetically?
You're super close, without any extra gems needed:
def add_to_value(hash, x)
hash.each {|key,value| hash[key] += x }
end
Just iterate the hash and update each value-by-key. #each returns the object being iterated on, so the result will be the original hash, which has been modified in place.
If you want a copy of the original hash, you can do that pretty easily, too:
def add_to_value(hash, x)
hash.each.with_object({}) {|(key, value), out| out[key] = value + x }
end
That'll define a new empty hash, pass it to the block, where it collects the new values. The new hash is returned from #with_object, and is thus returned out of add_to_value.
You can do the following to increment values:
hash = {}
{"a" => 1, "c" => 2,"b"=> 3}.each {|k,v| hash[k]=v+1}
hash
=>{"a"=>2, "c"=>3, "b"=>4}
And the hash will be sorted as you want.
The problem becomes trivial if you use certain gems, such as y_support. Type in your command line gem install y_support, and enjoy the extended hash iterators:
require 'y_support/core_ext/hash'
h = { "a"=>1, "c"=>3, "b"=>2 }
h.with_values do |v| v + 1 end
#=> {"a"=>2, "c"=>4, "b"=>3}
As for your sorting problem, I was unable to reproduce it.
Of course, a less elegant solution is possible without installing a gem:
h.each_with_object Hash.new do |(k, v), h| h[k] = v + 1 end
The gem also gives you Hash#with_keys (which modifies keys) and Hash#modify (which modifies both keys and values, kind of mapping from hash to hash), and banged versions Hash#with_values!, #with_keys! that modify the hash in place.
Is it possible to expose the key/value pair from an array of hashes in the parameter of the block?
array = [{:a=>'a'}, {:b=>'b'}] # an array of hashes
array.each {|key, value| puts "#{key},#{value}"}
array.map {|key, value| "(#{key},#{value})"}
array.inject([]) {|accum, (key,value)| key == :a ? value : accum}
Currently the results of the code block parameters |key, value| are (hash, nil)
I would like to get (symbol, string) in the declaration of the |key,value| parameters. Is this possible or am I stuck having to pass in a hash and extracting the key/value pair myself?
I know that passing a hash instead of an array will automatically give access to the key/value pair, but much of Ruby returns arrays.
UPDATE: It seems possible with arrays, but not hashes?
a = [['a','b'],['c','d']]
a.each {|(x,y)| puts "#{x}=>#{y}"} # => a=>b
# => c=>d
a.each {|x| p x} # => ["a", "b"]
# => ["c", "d"]
Ok.. If I catch you wright :
array = [{:a=>'a'}, {:b=>'b'}]
array.map {|k,v| [k,v]}
# => [[{:a=>"a"}, nil], [{:b=>"b"}, nil]]
you are getting above. But you want [[:a,"a"], [:b,"b"]] . No It is not possible. With #each or #map, when you have array of hashes like you given,you can't assign the block parameter k,v as :a,"a" and :b,"b" with each pass.
More simply try on your IRB,you will get to see the effect:
k,v = {:a=>'a'}
p k,v
# >> {:a=>"a"}
# >> nil
How to push inputs into a value of a hash? My problem is that I got multiple keys and all of them reference arrays.
{"A"=>["C"], "B"=>["E"], "C"=>["D"], "D"=>["B"]}
How can I push another String onto one of these? For example I want to add a "Z" to the array of key "A"?
Currently I either overwrite the former array or all data is in one.
Its about converting a Array ["AB3", "DC2", "FG4", "AC1", "AF4"] into a hash with {"A"=>["B", "C", "F"]}.
Any command <<, push, unshift will do a job
if h["A"]
h["A"] << "Z"
else
h["A"] = ["Z"]
end
You said your original problem is converting the array ["AB3", "DC2", "FG4", "AC1", "AF4"] into the hash {"A"=>["B", "C", "F"]}, which can be done like this:
Hash[a.group_by { |s| s[0] }.map { |k, v| [k, v.map { |s| s[1] }] }]
Or like this:
a.inject(Hash.new{|h, k| h[k]=[]}) { |h, s| h[s[0]] << s[1] ; h }
Note that Hash.new{|h, k| h[k]=[]} creates an array with a default value of [] (an empty array), so you'll always be able to use << to add elements to it.
Better approach:
Add a new class method in Hash as below:
class Hash
def add (k,v)
unless self.key?k
self[k] = [v]
else
self[k] = self[k] << v
end
self
end
end
h={}
h.add('A','B') #=> {"A"=>["B"]}
h.add('A','C') #=> {"A"=>["B", "C"]}
h.add('B','X') #=> {"A"=>["B", "C"], "B"=>["X"]}
Done.
This can be even more idiomatic according to your precise problem; say, you want to send multiple values at once, then code can be DRY-ed to handle multiple arguments.
Hope this helps.
All the best.
I'm looking to perform a conversion of the values in a Ruby hash from String to Integer.
I thought this would be fairly similar to the way you perform a conversion in a Ruby array (using the map method), but I have not been able to find an elegant solution that doesn't involve converting the hash to an array, flattening it, etc.
Is there a clean solution to do this?
Eg. From
x = { "a" => "1", "b" => "2", "c"=> "3" }
To
x = { "a" => 1, "b" => 2, "c" => 3 }
To avoid modifying the original Hash (unlike the existing answers), I'd use
newhash = x.reduce({}) do |h, (k, v)|
h[k] = v.to_i and h
end
If you're using Ruby 1.9, you can also use Enumerable#each_with_object to achieve the same effect a bit more cleanly.
newhash = x.each_with_object({}) do |(k, v), h|
h[k] = v.to_i
end
If you want to, you can also extract the logic into a module and extend the Hash class with it.
module HMap
def hmap
self.each_with_object({}) do |(k, v), h|
h[k] = yield(k, v)
end
end
end
class Hash
include HMap
end
Now you can use
newhash = x.hmap { |k, v| v.to_i } # => {"a"=>1, "b"=>2, "c"=>3}
My preferred solution:
Hash[x.map { |k, v| [k, v.to_i]}] #=> {"a"=>1, "b"=>2, "c"=>3}
A somewhat wasteful one (has to iterate over the values twice):
Hash[x.keys.zip(x.values.map(&:to_i))] #=> {"a"=>1, "b"=>2, "c"=>3}
Try this:
x.each{|k,v| x[k]=v.to_i}
p.keys.map { |key| p[key] = p[key].to_i }