I am pulling the following string from a CSV file, from cell A1, and storing it as a variable:
#{collector_id}
So, cell A1 reads #{collector_id}, and my code essentially does this:
test = #excel_cell_A1
However, if I then do this:
puts test
I get this:
#{collector_id}
I need #{collector_id} to read as the actual variable collector_id, not the code that I am using to call the variable. Is that possible?
Thanks for the help. I am using ruby 1.9.3.
You can use sub or gsub to replace expected input values:
collector_id = "foo"
test = '#{collector_id}'
test.sub("\#{collector_id}", "#{collector_id}") #=> "foo"
I would avoid the use of eval (or at least sanity check what you are running) to reduce the risk of running arbitrary code you receive from the CSV file.
Try this:
test_to_s = eval("\"#{ test }\"")
puts test_to_s
%q["#{ test }"] will build the string "#{collector_id}" (the double quotes are part of the string, "#{collector_id}".length == 17) which then will be evaluated as ruby code by eval
Related
I am running test with Capybara on Ruby. I got an error for this code
pos = rand languages.size
# advanced_search.adv_language_labels[pos].click
script = "$('label[for*='lang']:eq(" + pos.to_s + ")').click()"
page.execute_script script
How can I get this 'pos' value to the script so that I can run with execute_script command? Thanks.
The string you're generating looks like this:
$('label[for*='lang']:eq(5)').click()
Note there's an internal pair of single quotes that's closing out the label path before you mean to. You need to escape those.
$('label[for*=\'lang\']:eq(5)').click()
Does anyone know a way to directly use a MatchData object containing named captures as the input to a String template formatting operation (%)? When I attempt to do so, I get a "positional args mixed with named args" error.
s = "One-Two-Three"
re = /(?<first>.*?)-(?<second>.*?)-(?<third>.*)/
puts "%{second}" % s.match(re)
I found other ways to achieve the functional objective (ie by creating an array of the captures in the desired order and using positional templating), but the code is comparatively klunky.
Try this:
s = "One-Two-Three"
re = /(?<first>.*?)-(?<second>.*?)-(?<third>.*)/
match = s.match(re)
[match.names.map(&:to_sym), match.captures].transpose.to_h
# => {:first=>"One", :second=>"Two", :third=>"Three"}
What about using string interpolation directly:
puts "#{s.match(re)['second']}"
For ruby < 2.0 you want to use Hash[]:
m = s.match re
Hash[m.names.map(&:to_sym).zip m.captures]
#=> {:first=>"One", :second=>"Two", :third=>"Three"}
Sometimes if I've defined a a variable, for example
xyz="example"
and I'd like to refer back to xyz, I can either type xyz or #{xyz} in statements/loops etc.
My question is when do I use xyz and when do I use #{xyz}? And how do they differ?
#{} allows you to use any Ruby expression (not necessarily a variable) inside an interpolating quote (doubly-quoted strings, regular expressions...). It will evaluate the expression, convert the result to a string using the to_s method, then insert ("interpolate") the result into the string at that spot.
For example, if you have a string "Hello, apollo!" and want to replace the apollo with the contents of a variable, you could say "Hello, #{name}!".
You could even put a whole program inside a string:
"One plus two equals #{
def last_name_by_first_name(last_name)
People.find_by_last_name(last_name).first.first_name
end
find_by_last_name('Jack')
}!"
or
"#{a = 1} + #{b = 2} = #{a + b}"
(But please don't do that, it's a horrid way to write code. Sticking with variable look-ups and simple function calls should be enough for most purposes.)
Anywhere outside of a string (or other interpolating quote), #{} is an error.
So I have the following little script to make a file setup for organizing reports that we get.
#This script is to create a file structure for our survey data
require 'fileutils'
f = File.open('CustomerList.txt') or die "Unable to open file..."
a = f.readlines
x = 0
while a[x] != nil
Customer = a[x]
FileUtils.mkdir_p(Customer + "/foo/bar/orders")
FileUtils.mkdir_p(Customer + "/foo/bar/employees")
FileUtils.mkdir_p(Customer + "/foo/bar/comments")
x += 1
end
Everything seems to work before the while, but I keep getting:
'mkdir': Invalid argument - Cust001_JohnJacobSmith(JJS) (Errno::EINVAL)
Which would be the first line from the CustomerList.txt. Do I need to do something to the array entry to be considered a string? Am I mismatching variable types or something?
Thanks in advance.
The following worked for me:
IO.foreach('CustomerList.txt') do |customer|
customer.chomp!
["orders", "employees", "comments"].each do |dir|
FileUtils.mkdir_p("#{customer}/foo/bar/#{dir}")
end
end
with data like so:
$ cat CustomerList.txt
Cust001_JohnJacobSmith(JJS)
Cust003_JohnJacobSmith(JJS)
Cust002_JohnJacobSmith(JJS)
A few things to make it more like the ruby way:
Use blocks when opening a file or iterating through arrays, that way you don't need to worry about closing the file or accessing the array directly.
As noted by #inger, local vars start with lower case, customer.
When you want the value of a variable in a string usign #{} is more rubinic than concatenating with +.
Also note that we took off the trailing newline using chomp! (which changes the var in place, noted by the trailing ! on the method name)
Ruby 1.9.1, OSX 10.5.8
I'm trying to write a simple app that parses through of bunch of java based html template files to replace a period (.) with an underscore if it's contained within a specific tag. I use ruby all the time for these types of utility apps, and thought it would be no problem to whip up something using ruby's regex support. So, I create a Regexp.new... object, open a file, read it in line by line, then match each line against the pattern, if I get a match, I create a new string using replaceString = currentMatch.gsub(/./, '_'), then create another replacement as whole string by newReplaceRegex = Regexp.escape(currentMatch) and finally replace back into the current line with line.gsub(newReplaceRegex, replaceString) Code below, of course, but first...
The problem I'm having is that when accessing the indexes within the returned MatchData object, I'm getting the first result twice, and it's missing the second sub string it should otherwise be finding. More strange, is that when testing this same pattern and same test text using rubular.com, it works as expected. See results here
My pattern:
(<(?:WEBOBJECT|webobject) (?:NAME|name)=(?:[a-zA-Z0-9]+.)+(?:[a-zA-Z0-9]+)(?:>))
Text text:
<WEBOBJECT NAME=admin.normalMode.someOtherPatternWeDontWant.moreThatWeDontWant>moreNonMatchingText<WEBOBJECT NAME=admin.SecondLineMatch>AndEvenMoreNonMatchingText
Here's the relevant code:
tagRegex = Regexp.new('(<(?:WEBOBJECT|webobject) (?:NAME|name)=(?:[a-zA-Z0-9]+\.)+(?:[a-zA-Z0-9]+)(?:>))+')
testFile = File.open('RegexTestingCompFix.txt', "r+")
lineCount=0
testFile.each{|htmlLine|
lineCount += 1
puts ("Current line: #{htmlLine} at line num: #{lineCount}")
tagMatch = tagRegex.match(htmlLine)
if(tagMatch)
matchesArray = tagMatch.to_a
firstMatch = matchesArray[0]
secondMatch = matchesArray[1]
puts "First match: #{firstMatch} and second match #{secondMatch}"
tagMatch.captures.each {|lineMatchCapture|
puts "Current capture for tagMatches: #{lineMatchCapture} of total match count #{matchesArray.size}"
#create a new regex using the match results; make sure to use auto escape method
originalPatternString = Regexp.escape(lineMatchCapture)
replacementRegex = Regexp.new(originalPatternString)
#replace any periods with underscores in a copy of lineMatchCapture
periodToUnderscoreCorrection = lineMatchCapture.gsub(/\./, '_')
#replace original match with underscore replaced copy within line
htmlLine.gsub!(replacementRegex, periodToUnderscoreCorrection)
puts "The modified htmlLine is now: #{htmlLine}"
}
end
}
I would think that I should get the first tag in matchData[0] then the second tag in matchData1, or, what I'm really doing because I don't know how many matches I'll get within any given line is matchData.to_a.each. And in this case, matchData has two captures, but they're both the first tag match
which is: <WEBOBJECT NAME=admin.normalMode.someOtherPatternWeDontWant.moreThatWeDontWant>
So, what the heck am I doing wrong, why does rubular test give me the expected results?
You want to use the on String#scan instead of the Regexp#match:
tag_regex = /<(?:WEBOBJECT|webobject) (?:NAME|name)=(?:[a-zA-Z0-9]+\.)+(?:[a-zA-Z0-9]+)(?:>)/
lines = "<WEBOBJECT NAME=admin.normalMode.someOtherPatternWeDontWant.moreThatWeDontWant>moreNonMatchingText\
<WEBOBJECT NAME=admin.SecondLineMatch>AndEvenMoreNonMatchingText"
lines.scan(tag_regex)
# => ["<WEBOBJECT NAME=admin.normalMode.someOtherPatternWeDontWant.moreThatWeDontWant>", "<WEBOBJECT NAME=admin.SecondLineMatch>"]
A few recommendations for next ruby questions:
newlines and spaces are your friends, you don't loose points for using more lines on your code ;-)
use do-end on blocks instead of {}, improves readability a lot
declare variables in snake case (hello_world) instead of camel case (helloWorld)
Hope this helps
I ended up using the String.scan approach, the only tricky point there was figuring out that this returns an array of arrays, not a MatchData object, so there was some initial confusion on my part, mostly due to my ruby green-ness, but it's working as expected now. Also, I trimmed the regex per Trevoke's suggestion. But snake case? Never...;-) Anyway, here goes:
tagRegex = /(<(?:webobject) (?:name)=(?:\w+\.)+(?:\w+)(?:>))/i
testFile = File.open('RegexTestingCompFix.txt', "r+")
lineCount=0
testFile.each do |htmlLine|
lineCount += 1
puts ("Current line: #{htmlLine} at line num: #{lineCount}")
oldMatches = htmlLine.scan(tagRegex) #oldMatches thusly named due to not explicitly using Regexp or MatchData, as in "the old way..."
if(oldMatches.size > 0)
oldMatches.each_index do |index|
arrayMatch = oldMatches[index]
aMatch = arrayMatch[0]
#create a new regex using the match results; make sure to use auto escape method
replacementRegex = Regexp.new(Regexp.escape(aMatch))
#replace any periods with underscores in a copy of lineMatchCapture
periodToUnderscoreCorrection = aMatch.gsub(/\./, '_')
#replace original match with underscore replaced copy within line, matching against the new escaped literal regex
htmlLine.gsub!(replacementRegex, periodToUnderscoreCorrection)
puts "The modified htmlLine is now: #{htmlLine}"
end # I kind of still prefer the brackets...;-)
end
end
Now, why does MatchData work the way it does? It seems like it's behavior is a bug really, and certainly not very useful in general if you can't get it provide a simple means of accessing all the matches. Just my $.02
Small bits:
This regexp helps you get "normalMode" .. But not "secondLineMatch":
<webobject name=\w+\.((?:\w+)).+> (with option 'i', for "case insensitive")
This regexp helps you get "secondLineMatch" ... But not "normalMode":
<webobject name=\w+\.((?:\w+))> (with option 'i', for "case insensitive").
I'm not really good at regexpt but I'll keep toiling at it.. :)
And I don't know if this helps you at all, but here's a way to get both:
<webobject name=admin.(\w+) (with option 'i').