I have an array in Ruby which has values as follows
xs = %w(2.0.0.1
2.0.0.6
2.0.1.10
2.0.1.5
2.0.0.8)
and so on. I want to sort the array such that the final result should be something like this :
ys = %w(2.0.0.1
2.0.0.6
2.0.0.8
2.0.1.5
2.0.1.10)
I have tried using the array.sort function, but it places "2.0.1.10" before "2.0.1.5". I am not sure why that happens
Using a Schwartzian transform (Enumerable#sort_by), and taking advantage of the lexicographical order defined by an array of integers (Array#<=>):
sorted_ips = ips.sort_by { |ip| ip.split(".").map(&:to_i) }
Can you please explain a bit more elaborately
You cannot compare strings containing numbers: "2" > "1", yes, but "11" < "2" because strings are compared lexicographically, like words in a dictionary. Therefore, you must convert the ip into something than can be compared (array of integers): ip.split(".").map(&:to_i). For example "1.2.10.3" is converted to [1, 2, 10, 3]. Let's call this transformation f.
You could now use Enumerable#sort: ips.sort { |ip1, ip2| f(ip1) <=> f(ip2) }, but check always if the higher abstraction Enumerable#sort_by can be used instead. In this case: ips.sort_by { |ip| f(ip) }. You can read it as "take the ips and sort them by the order defined by the f mapping".
Split your data into chunks by splitting on '.'. There is no standard function to do it as such so you need to write a custom sort to perform this.
And the behaviour you said about 2.0.1.10 before 2.0.1.5 is expected because it is taking the data as strings and doing ASCII comparisons, leading to the result that you see.
arr1 = "2.0.0.1".split('.')
arr2 = "2.0.0.6".split('.')
Compare both arr1 and arr2 element by element, for all the data in your input.
Related
I need to create functionality which is going to process the dictionary (dictionary.txt file). The goal is to find all six-letter words that are built of two concatenated smaller words e.g.:
con + vex => convex
tail + or => tailor
we + aver => weaver
Of course, there may be some words inside the file that are not 6 letters long, but these can be easily sifted out using a simple method:
def cleanup_file
file_data = File.read('dictrionary.txt').split
file_data.reject! { |word| word.size < 6 }
end
But now comes the problem - how to find if the other strings in the array are made of two connected smaller words ?
[Edit]
Sample dictionary.txt file here
Thinking just in a pseudo code solution, but you should:
Iterate every line of the dictionary and store the words in 6 different arrays by the length of each word.
Make sure that all words are downcased, there are no duplicates and all the values are sorted, so later you could properly use .bsearch in the arrays.
Iterate the length-6 array (for example convex) and look for a match of the first character of the current word in the length-1 array (c for the given example) and in the length-5 array (onvex). If there's a match, save the words.
Then keep looking in the length-2 and length-4 arrays for matches (co and nvex correspondingly) and save a match.
Finally, look both parts of the string in the length-3 array (con and vex) and save any match
Look for the next 6 characters string until you've finished.
Most likely there are better ways to solve this, like in the first iteration inserting each word in its corresponding array using .bsearch_index to sort and not inserting duplicates in the same iteration, but most of the workload is going to be in the 2nd iteration and binary searches work in O(log n) time, so I guess it should work quick enough.
Suppose the dictionary is as follows.
dictionary = [
"a", "abased", "act", "action", "animal", "ape", "apeman",
"art", "assertion", "bar", "barbed", "barhop", "based", "be",
"become", "bed", "come", "hop", "ion", "man"
]
I assume that, like most dictionaries, dictionary is sorted.
First compute the following hash.
by_len = dictionary.each_with_object({}) do |w,h|
len = w.length
(h[len] ||= []) << w if len < 7
end
#=> {1=>["a"],
# 6=>["abased", "action", "animal", "apeman", "barbed",
# "barhop", "become"],
# 3=>["act", "ape", "art", "bar", "bed", "hop", "ion", "man"],
# 5=>["based"],
# 2=>["be"],
# 4=>["come"]}
Each key is a word length (1-6) and each value is an array of words from dictionary whose length is the value of the key.
Next I will define a helper function that returns true or false depending on whether a given array of words (list) contains a given word (word).
def found?(list, word)
w = list.bsearch { |w| w >= word }
w && w == word
end
For example:
found?(by_len[3], "art")
#=> true
found?(by_len[3], "any")
#=> false
See Array#bsearch.
We now extract the words of interest:
by_len[6].select { |w| (1..5).any? { |i|
found?(by_len[i], w[0,i]) && found?(by_len[6-i], w[i..-1]) } }
#=> ["abased", "action", "apeman", "barbed", "barhop", "become"]
In my web page there are 5 values given in the text field(like $10, $20, $30, $40 and $50) and I am trying to sum the values using ruby and selenium WebDriver.
Here is my code:
def get_sum_of_all_elements()
#logger.info("Searching element #{value1, value2, value3, value4, value5}");
allelements = #driver.find_elements(:id = "lbl_val_")
#logger.info("Total Elements Found with locator #{locator} are : #{allelements.size}");
if allelements.start_with?("$")
allelements = "((allelements))".tr('$', '') #removing '$' sign from values
iSum =0
allelements.each do|i|
iSum += i
end
end
end
I am expecting to see output as 150. Do I need to store values in an array?
Any help would be appreciated.
There a couple of things you should modify in your code to make it work:
Fix how arguments are passed to find_elements; it should be id: "lbl_val_".
find_elements returns an array of WebDriver::Element objects, so you must check the value for each object.
The string "Searching element #{value1, value2, value3, value4, value5}" is not valid since you are trying to interpolate the value of 5 variables chained with a comma. You either need to interplate only the variable (keeping commas as strings) or use square brackets ([]) to interpolate an array.
Now your code should look something like this1:
def get_sum_of_all_elements
#logger.info("Searching element #{[value1, value2, value3, value4, value5]}")
allelements = #driver.find_elements(id: "lbl_val_")
#logger.info("Total Elements Found with locator #{locator} are : #{allelements.size}");
if allelements.all? { |elem| elem.value.start_with?("$") }
elements = allelements.map { |elem| elem.value.tr('$', '').to_i }
elements.reduce(:+)
end
end
A few things to note:
Parenthesis (()) were removed in method definition, ruby doesn't need them when no arguments are passed.
There is no longer need to assign the final value to a variable (e.g iSum) since ruby will return the result of last evaluated code.
If any value doesn't start with "$", it will return false. You could change this by adding a default value after if block.
Semicolons (;) were removed, you don't need them in ruby (unless you want to chain multiple statements in a singe line).
One more thing, the variables value1, value2, value3, value4, value5 and locator doesn't seem to be set anywhere in your method; you must set them within your method (or pass them as arguments) or you will get an error.
1 This considers the same logic that you seemed to be looking for in your code, that is, sum all values only if all of them start with "$".
It's hard to say exactly what you are trying to do, but this might help. I assume you have an array of string values with dollar signs:
>> allelements = ["$10", "$20", "$30", "$40", "$50"]
=> ["$10", "$20", "$30", "$40", "$50"]
We can make a new array stripping out all non-numeric characters and transforming the string values to integers:
>> integers = allelements.map { |e| e.gsub(/[^\d]/, '').to_i }
=> [10, 20, 30, 40, 50]
Now use inject to sum the values:
>> integers.inject(:+)
=> 150
how to write a code snippet Ruby that will flatten an array of arbitrarily nested arrays of integers into a flat array of integers. e.g. [[1,2,[3]],4] -> [1,2,3,4]. Please don't use any built-in flatten functions in either language.
Here's one solution without using the built-in flatten method. It involves recursion
def flattify(array)
array.each_with_object([]) do |element, flattened|
flattened.push *(element.is_a?(Array) ? flattify(element) : element)
end
end
I tested this out in irb.
flattify([[1,2,[3],4])
=> [1,2,3,4]
arr = [[1,2,[3]],4]
If, as in you example, arr contains only numbers, you could (as opposed to "should") do this:
eval "[#{arr.to_s.delete('[]')}]"
=> [1, 2, 3, 4]
Often in my tasks I've got to read previously defined amount of numbers in line and of course I know how they are separated. For example, let's say it'd be two coordinates separated with space. Here is what I actually do to read this line:
line = gets.split(' ').map(&:to_i)
It's fine, but I either have to call line[0] .. line[1] or add two lines for a = line[0] ...
Is there any way to read defined amount of numbers and assign them to variables, not an array?
EDIT/TL:DR: In the other words: I'm looking for Ruby's scanf("%d %d", &x, &y);
Just do this:
x, y = gets.split(' ').map(&:to_i)
puts "x: #{x}"
puts "y: #{y}"
If you do not know how many values will be in the string you cannot assign each value to a local variable. That's because you cannot use parallel assignment (see my comment on #K's answer) and, since Ruby v1.9, you cannot define local variables dynamically (e.g, eval("x=1") doesn't work).
You can assign the values to instance variables dynamically, like so:
arr = gets.chomp.split(/\s+/)
or
arr = gets.split(/\s+/).map(&:to_i)
depending on your needs.
Suppose
arr = [1, 2, 3, 4]
Then:
arr.each_with_index { |x,i| instance_variable_set("#my_var#{i}", x) }
instance_variable_get(:#my_var0) #=> 1
instance_variable_get(:#my_var1) #=> 2
instance_variable_get(:#my_var2) #=> 3
instance_variable_get(:#my_var3) #=> 4
But why would you want to do this?
Edit:
You know that gets will return a string that contains two substrings representing integers, separated by one or more spaces, and you wish to assign those two integers to variables x and y.
I expect you don't mind if unnamed temporary arrays are created, you just don't want any named arrays, such as:
arr = gets.map(&:to_i)
x,y = arr
If, however, you want to do this without creating any arrays, this might work:
s = gets #=> "1 -2\n"
x = s[/(-?\d+)\s/,1].to_i #=> 1
y = s[/\s(-?\d+)/,1].to_i #=> -2
I say "might" because I don't know if Ruby is creating any arrays in the background for her own use.
Alternatively, you could use positive lookarounds and no capture groups:
x = s[/-?\d+(?=\s)/].to_i #=> 1
y = s[/(?<=\s)-?\d+/].to_i #=> -2
I'm having a problem with lua's table.concat, and suspect it is just my ignorance, but cannot find a verbose answer to why I'm getting this behavior.
> t1 = {"foo", "bar", "nod"}
> t2 = {["foo"]="one", ["bar"]="two", ["nod"]="yes"}
> table.concat(t1)
foobarnod
> table.concat(t2)
The table.concat run on t2 provides no results. I suspect this is because the keys are strings instead of integers (index values), but I'm not sure why that matters.
I'm looking for A) why table.concat doesn't accept string keys, and/or B) a workaround that would allow me to concatenate a variable number of table values in a handful of lines, without specifying the key names.
Because that's what table.concat is documented as doing.
Given an array where all elements are strings or numbers, returns table[i]..sep..table[i+1] ยทยทยท sep..table[j]. The default value for sep is the empty string, the default for i is 1, and the default for j is the length of the table. If i is greater than j, returns the empty string.
Non-array tables have no defined order so table.concat wouldn't be all that helpful then anyway.
You can write your own, inefficient, table concat function easily enough.
function pconcat(tab)
local ctab, n = {}, =1
for _, v in pairs(tab) do
ctab[n] = v
n = n + 1
end
return table.concat(ctab)
end
You could also use next manually to do the concat, etc. yourself if you wanted to construct the string yourself (though that's probably less efficient then the above version).