create comma separated string in the First element of an array Ruby - ruby

So this may seem odd, and I have done quite a bit of googling, however, I am not really a programmer, (sysops) and trying to figure out how to pass data to the AWS API in the required format, which does seem a little odd.
So, working with resources in AWS, I need to pass tags which are keys and values. The key is a string. The value is a comma separated string, in the first element of an array. So in Ruby terms, looks like this.
{env => ["stage,qa,dev"]}
and not
{env => ["stage","qa","dev"]}
I'm created an admittedly. not a very pretty little app that will allow me to run ssm documents on targeted instances in aws.
I can get the string into an array element using this class I created
class Tags
attr_accessor :tags
def initialize
#tags = {"env" => nil ,"os" => nil ,"group" => nil }
end
def set_values()
puts "please enter value/s for the following keys, using spaces or commas for multiple values"
#tags.each { |key,value|
print "enter #{key} value/s: "
#tags[key] = [gets.strip.chomp]
#tags[key] = Validate.multi_value(tags[key])
}
end
end
I then call this Validate.multi_value passing in the created Array, but it spits an array of my string value back.
class Validate
def self.multi_value(value)
if value.any?{ |sub_string| sub_string.include?(",") || sub_string.include?(" ") }
value = value[0].split(/[,\s]+/)
return value
else
return value
end
end
end
Using pry, I've seen it gets for example ["stage dev qa"] then the if statement does work, then it spits out ["stage","dev","qa"].
and I need it to output ["stage,dev,qa"] but for the life of me, I can't make it work.
I hope that's clear.
If you have any suggestions, I'd be most grateful.
I'm not hugely experienced at ruby and the may be class methods that I've missed.

If your arrays are always coming through in the format ["stage dev qa"] then first we need to split the one string into the parts we want:
arr = ["stage dev qa"]
arr.split(' ')
=> ["stage", "dev", "qa"]
Then we need to join them with the comma:
arr.split(' ').join(',')
=> "stage,dev,qa"
And finally we need to wrap it in an array:
[arr.first.split(' ').join(',')]
=> ["stage,dev,qa"]
All together:
def transform_array(arr)
[arr.first.split(' ').join(',')]
end
transform_array(['stage dev qa'])
=> ['stage,dev,qa']
More info: How do I convert an array of strings into a comma-separated string?

I see no point in creating a class here when a simple method would do.
def set_values
["env", "os", "group"].map do |tag|
puts "Please enter values for #{tag}, using spaces or commas"
print "to separate multiple values: "
gets.strip.gsub(/[ ,]+/, ',')
end
end
Suppose, when asked, the user enters, "stage dev,qa" (for"env"), "OS X" (for"OS") and "Hell's Angels" for "group". Then:
set_values
#=> ["stage,dev,qa", "OS,X", "Hell's,Angels"]
If, as I suspect, you only wish to convert spaces to commas for "env" and not for "os" or "group", write:
def set_values
puts "Please enter values for env, using spaces or commas"
print "to separate multiple values: "
[gets.strip.gsub(/[ ,]+/, ',')] +
["os", "group"].map do |tag|
print "Please enter value for #{tag}: "
gets.strip
end
end
set_values
#=> ["stage,dev,ga", "OS X", "Hell's Angels"]
See Array#map, String#gsub and Array#+.
gets.strip.gsub(/[ ,]+/, ',') merely chains the two operations s = gets.strip and s.gsub(/[ ,]+/, ','). Chaining is commonplace in Ruby.
The regular expression used by gsub reads, "match one or more spaces or commas", [ ,] being a character class, requiring one of the characters in the class be matched, + meaning that one or more of those spaces or commas are to be matched. If the string were "a , b,, c" there would be two matches, " , " and ",, "; gsub would convert both to a single comma.
Using print rather than puts displays the user's entry on the same line as the prompt, immediately after ": ", rather than on the next line. That is of course purely stylistic.
Often one would write gets.chomp rather than gets.strip. Both remove newlines and other whitespace at the end of the string, strip also removes any whitespace at the beginning of the string. strip is probably best in this case.

What do you think about this?, everything gets treated in the Validates method. I don't know if you wanted to remove repeated values, but, just in case I did, so a
"this string,, has too many,,, , spaces"
will become
"this,string,has,too,many,spaces"
and not
"this,,,,string,,,has,too,,many,,,,,,spaces"
Here's the code
class Tags
attr_accessor :tags
# initializes the class (no change)
#
def initialize
#tags = {"env" => nil ,"os" => nil ,"group" => nil }
end
# request and assign the values <- SOME CHANGES
#
def set_values
puts "please enter value/s for the following keys, using spaces or commas for multiple values"
#tags.each do |key,value|
print "enter #{key} value/s: "
#tags[key] = Validate.multi_value( gets )
end
end
end
class Validate
# Sets the array
#
def self.multi_value(value)
# Remove leading spaces, then remove special chars,
# replace all spaces with commas, then remove repetitions
#
[ value.strip.delete("\n","\r","\t","\rn").gsub(" ", ",").squeeze(",") ]
end
end
EDITED, thanks lacostenycoder

Related

How to match and replace pattern without regex?

I was recently asked this in an interview and was figuring out a way to do this without using regex in Ruby as I was told it would be a bonus if you can solve it without using regex.
Question: Assume that the hash has 1 million key, value pairs and we have to be able to sub the variables in the string that are between % % this pattern. How would I be able to do this without regex.
We have a string str = "%greet%! Hi there, %var_1% that can be any other %var_2% injected to the %var_3%. Nice!, goodbye)"
we have a hash called dict = { greet: 'Hi there', var_1: 'FIRST VARIABLE', var_2: 'values', var_3: 'string', }
This was my solution:
def template(str, dict)
vars = value.scan(/%(.*?)%/).flatten
vars.each do |var|
value = value.gsub("%#{var}%", dict[var.to_sym])
end
value
end
There are many ways to solve this, but you will probably need some kind of parsing and / or lexical analysis if you don't want to use built-in pattern matching.
Let's keep it very simple and say that your string's content falls into two categories: text and variable which are separated by %, e.g. (you could also think of the variables being enclosed by %, but that's harder to implement)
str = "Hello %name%, hope to see you %when%!"
# TTTTTT VVVV TTTTTTTTTTTTTTTTTT VVVV T
As you can see, the categories are alternating. We can utilize this and write a little helper method that turns a string into a list of [type, value] pairs, something like this:
def each_part(str)
return enum_for(__method__, str) unless block_given?
type = [:text, :var].cycle
buf = ''
str.each_char do |char|
if char != '%'
buf << char
else
yield type.next, buf
buf = ''
end
end
yield type.next, buf
end
It starts by defining an enumerator that will cycle between the two types and an empty buffer. It will then read each_char from the string. If the char is not %, it will just append it to the buffer and keep reading. Once it encounters a %, it will yield the current buffer along with the type and start a new buffer (next will also switch the type). After the loop ends, it will yield once more to output the remaining characters.
It outputs this kind of data:
each_part(str).to_a
#=> [[:text, "Hello "],
# [:var, "name"],
# [:text, ", hope to see you "],
# [:var, "when"],
# [:text, "!"]]
We can use this to convert the string:
dict = { name: 'Tom', when: 'soon' }
output = ''
each_part(str) do |type, value|
case type
when :text
output << value
when :var
output << dict[value.to_sym]
end
end
p output
#=> "Hello Tom, hope to see you soon!"
You could of course combine parsing and evaluation, but I like the separation. An full-fledged parser might involve even more steps.
A very simple approach:
First, split the string on '%':
str = "%greet%! Hi there, %var_1% that can be any other %var_2% injected to the %var_3%. Nice!, goodbye)"
chunks = str.split('%')
Now we can assume given the way the problem has been specified, that every other "chunk" will be a key to replace. Iterating with the index will make that easier to figure out.
chunks.each_with_index { |c, i| chunks[i] = (i.even? ? c : dict[c.to_sym]) }.join
Result:
"Hi there! Hi there, FIRST VARIABLE that can be any other values injected to the string. Nice!, goodbye)"
Note: this does not handle malformed input well at all.

How to output certain characters and add characters in certain positions in ruby?

I'm not sure where I went wrong, but I created a class called phone number that takes a parameter of ph. ph gets converted to a string. So, when 123456789 is inputted like a.PhoneNumber(123456789) it should input out (123) 456-7890 and when a.area_code is called it should give #123, etc.
Why does none of my scan methods work correctly?
Can I use the split method to pull out only #123 from 1234567890?
class PhoneNumber
def initialize (ph)
#ph = ph
#ph.insert(0, '#')
#ph.scan(/.{0,1}/).join('( ')
#ph.scan(/.{3,4}/).join(')')
#ph.scan(/.{3,5}/).join('- ')
end
def to_s
#ph
end
def area_code
#ph.split(0,2)
end
end
print "Please enter the number: "
puts a = PhoneNumber.new(gets.strip)
puts a.area_code
The scan methods don't work because the Regex you are using are not doing what I think you think it should be doing.
.{0,1} matches anything between 0 and 1 character. That's why they just return the match string iteratively
#ph.scan(/.{0,1}/) #=> "#1234567890"
#ph.scan(/.{3,4}/) #=> "#1234567890"
#ph.scan(/.{4,5}/) #=> "#1234567890"
One possible way to fix this is to use indexes to get split the #ph in three parts. Alternatively, you can also use something like this to split the number in groups
#ph.scan(/(\d{3})(\d{3})(\d{4})/) #=> [["123", "456", "7890"]]
First argument to split must be a String or Regexp in #ph.split(0,2)
You can define area_code something like this if the first char of #ph is #
def area_code
#split[1,3]
end

How to scan text/string for certain words and gsub them out with desired words

I want to create a 'swearscan' that can scan user text and swap the swear words out for 'censored'. I thought I coded it properly, but obviously not because I'll show you what's happening. Someone please help!
And since its stackflow we'll substitute swear words for something else
puts "Input your sentence here: "
text = gets.downcase.strip
swear_words = {'cat' => 'censored', 'dog' => 'censored', 'cow' => 'censored'}
clean_text = swear_words.each do |word, clean|
text.gsub(word,clean)
end
puts clean_text
When I ran this program (with the actual swearwords) all it would return is the hash like so: catcensoreddogcensoredcowcensored. What is wrong with my code that it's returning the hash and not the clean_text with everything substituted out?
This works for me:
puts "Input your sentence here: "
text = gets.downcase.strip
swear_words = {'cat' => 'censored', 'dog' => 'censored', 'cow' => 'censored'}
swear_words.each do |word, clean| # No need to copy here
text.gsub!(word,clean) # Changed from gsub
end
puts text # Changed from clean_text
What is wrong is that gsub does not change the original string, but you are expecting it to do so. Using gsub! will change the original string. You are also wrong to expect each to return something in it. Just refer to text in the end to get the replaced string.
By the way, if the replacement strings are all the same 'censored', then it does not make sense to use a hash there. You should just have an array of the swear words, and put the replacement string in the gsub! method directly (or define it as a constant in some other place).

Ruby- find strings that contain letters in an array

I've googled everywhere and can't seem to find an example of what I'm looking for. I'm trying to learn ruby and i'm writing a simple script. The user is prompted to enter letters which are loaded into an array. The script then goes through a file containing a bunch of words and pulls out the words that contain what is in the array. My problem is that it only pulls words out if they are in order of the array. For example...
characterArray = Array.new;
puts "Enter characters that the password contains";
characters = gets.chomp;
puts "Searching words containing #{characters}...";
characterArray = characters.scan(/./);
searchCharacters=characterArray[0..characterArray.size].join;
File.open("dictionary.txt").each { |line|
if line.include?(searchCharacters)
puts line;
end
}
If i was to use this code and enter "dog"
The script would return
dog
doggie
but i need the output to return words even if they're not in the same order. Like...
dog
doggie
rodge
Sorry for the sloppy code. Like i said still learning. Thanks for your help.
PS. I've also tried this...
File.open("dictionary.txt").each { |line|
if line =~ /[characterArray[0..characterArray.size]]/
puts line;
end
}
but this returns all words that contain ANY of the letters the user entered
First of all, you don't need to create characterArray yourself. When you assign result of function to a new variable, it will work without it.
In your code characters will be, for example, "asd". characterArray then will be ["a", "s", "d"]. And searchCharacters will be "asd" again. It seems you don't need this conversion.
characterArray[0..characterArray.size] is just equal to characterArray.
You can use each_char iterator to iterate through characters of string. I suggest this:
puts "Enter characters that the password contains";
characters = gets.chomp;
File.open("dictionary.txt").each { |line|
unless characters.each_char.map { |c| line.include?(c) }.include? false
puts line;
end
}
I've checked it works properly. In my code I make an array:
characters.each_char.map { |c| line.include?(c) }
Values of this array will indicate: true - character found in line, false - character not found. Length of this array equals to count of characters in characters. We will consider line good if there is no false values.

Ruby Regex not matching

I'm writing a short class to extract email addresses from documents. Here is my code so far:
# Class to scrape documents for email addresses
class EmailScraper
EmailRegex = /\A[\w+\-.]+#[a-z\d\-.]+\.[a-z]+\z/i
def EmailScraper.scrape(doc)
email_addresses = []
File.open(doc) do |file|
while line = file.gets
temp = line.scan(EmailRegex)
temp.each do |email_address|
puts email_address
emails_addresses << email_address
end
end
end
return email_addresses
end
end
if EmailScraper.scrape("email_tests.txt").empty?
puts "Empty array"
else
puts EmailScraper.scrape("email_tests.txt")
end
My "email_tests.txt" file looks like so:
example#live.com
another_example90#hotmail.com
example3#diginet.ie
When I run this script, all I get is the "Empty array" printout. However, when I fire up irb and type in the regex above, strings of email addresses match it, and the String.scan function returns an array of all the email addresses in each string. Why is this working in irb and not in my script?
Several things (some already mentioned and expanded upon below):
\z matches to the end of the string, which with IO#gets will typically include a \n character. \Z (upper case 'z') matches the end of the string unless the string ends with a \n, in which case it matches just before.
the typo of emails_addresses
using \A and \Z is fine while the entire line is or is not an email address. You say you're seeking to extract addresses from documents, however, so I'd consider using \b at each end to extract emails delimited by word boundaries.
you could use File.foreach()... rather than the clumsy-looking File.open...while...gets thing
I'm not convinced by the Regex - there's a substantial body of work already around:
There's a smarter one here: http://www.regular-expressions.info/email.html (clicking on that odd little in-line icon takes you to a piece-by-piece explanation). It's worth reading the discussion, which points out several potential pitfalls.
Even more mind-bogglingly complex ones may be found here.
class EmailScraper
EmailRegex = /\A[\w+\-.]+#[a-z\d\-.]+\.[a-z]+\Z/i # changed \z to \Z
def EmailScraper.scrape(doc)
email_addresses = []
File.foreach(doc) do |line| # less code, same effect
temp = line.scan(EmailRegex)
temp.each do |email_address|
email_addresses << email_address
end
end
email_addresses # "return" isn't needed
end
end
result = EmailScraper.scrape("email_tests.txt") # store it so we don't print them twice if successful
if result.empty?
puts "Empty array"
else
puts result
end
Looks like you're putting the results into emails_addresses, but are returning email_addresses. This would mean that you're always returning the empty array you defined for email_addresses, making the "Empty array" response correct.
You have a typo, try with:
class EmailScraper
EmailRegex = /\A[\w+\-.]+#[a-z\d\-.]+\.[a-z]+\z/i
def EmailScraper.scrape(doc)
email_addresses = []
File.open(doc) do |file|
while line = file.gets
temp = line.scan(EmailRegex)
temp.each do |email_address|
puts email_address
email_addresses << email_address
end
end
end
return email_addresses
end
end
if EmailScraper.scrape("email_tests.txt").empty?
puts "Empty array"
else
puts EmailScraper.scrape("email_tests.txt")
end
You used at the end \z try to use \Z according to http://www.regular-expressions.info/ruby.html it has to be a uppercase Z to match the end of the string.
Otherwise try to use ^ and $ (matching the start and the end of a row) this worked for me here on Regexr
When you read the file, the end of line is making the regex fail. In irb, there probably is no end of line. If that is the case, chomp the lines first.
regex=/\A[\w+\-.]+#[a-z\d\-.]+\.[a-z]+\z/i
line_from_irb = "example#live.com"
line_from_file = line_from_irb +"/n"
p line_from_irb.scan(regex) # => ["example#live.com"]
p line_from_file.scan(regex) # => []

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