I have a rails app in which users input numbers in large quantities. They often use the thousands delimiter (e.g. 1,000,000,000) to help keep their large numbers human-readable (I don't want to disallow delimiter because doing so would increase the chance of incorrect data).
ActiveSupport/Rails has the handy method number_with_delimiter so that an int 1234567 is displayed as 1,234,567. Is there a method to do the reverse?
note: I don't want to simply strip out a comma, since commas are used as a decimal point in many locales (e.g. European)
To answer your general question, you can determine the "delimiter" (thousands-separator) and the "separator" (decimal separator) from the Rails localization system directly:
I18n.t('number.format.separator') # <= '.' on a US English system
I18n.t('number.format.delimiter') # <= ',' on a US English system
So you can do this:
better = input_string.gsub(I18n.t('number.format.delimiter'), '')
Or, if you prefer be more aggressive and remove all non-numerical and non-decimal input:
better = input_string.gsub(/[^\d#{I18n.t('number.format.separator')}]/, '')
Note, though, that the second example will also remove negative signs, if that matters to you.
It is also worth noting that ActiveRecord will do this for you:
my_model.update_attributes(some_float: "1,234.50") # <= sets some_float to 1234.5
Related
I've been looking for a good way to see if a string of items are all numbers, and thought there might be a way of specifying a range from 0 to 9 and seeing if they're included in the string, but all that I've looked up online has really confused me.
def validate_pin(pin)
(pin.length == 4 || pin.length == 6) && pin.count("0-9") == pin.length
end
The code above is someone else's work and I've been trying to identify how it works. It's a pin checker - takes in a set of characters and ensures the string is either 4 or 6 digits and all numbers - but how does the range work?
When I did this problem I tried to use to_a? Integer and a bunch of other things including ranges such as (0..9) and ("0..9) and ("0".."9") to validate a character is an integer. When I saw ("0-9) it confused the heck out of me, and half an hour of googling and youtube has only left me with regex tutorials (which I'm interested in, but currently just trying to get the basics down)
So to sum this up, my goal is to understand a more semantic/concise way to identify if a character is an integer. Whatever is the simplest way. All and any feedback is welcome. I am a new rubyist and trying to get down my fundamentals. Thank You.
Regex really is the right way to do this. It's specifically for testing patterns in strings. This is how you'd test "do all characters in this string fall in the range of characters 0-9?":
pin.match(/\A[0-9]+\z/)
This regex says "Does this string start and end with at least one of the characters 0-9, with nothing else in between?" - the \A and \z are start-of-string and end-of-string matchers, and the [0-9]+ matches any one or more of any character in that range.
You could even do your entire check in one line of regex:
pin.match(/\A([0-9]{4}|[0-9]{6})\z/)
Which says "Does this string consist of the characters 0-9 repeated exactly 4 times, or the characters 0-9, repeated exactly 6 times?"
Ruby's String#count method does something similar to this, though it just counts the number of occurrences of the characters passed, and it uses something similar to regex ranges to allow you to specify character ranges.
The sequence c1-c2 means all characters between c1 and c2.
Thus, it expands the parameter "0-9" into the list of characters "0123456789", and then it tests how many of the characters in the string match that list of characters.
This will work to verify that a certain number of numbers exist in the string, and the length checks let you implicitly test that no other characters exist in the string. However, regexes let you assert that directly, by ensuring that the whole string matches a given pattern, including length constraints.
Count everything non-digit in pin and check if this count is zero:
pin.count("^0-9").zero?
Since you seem to be looking for answers outside regex and since Chris already spelled out how the count method was being implemented in the example above, I'll try to add one more idea for testing whether a string is an Integer or not:
pin.to_i.to_s == pin
What we're doing is converting the string to an integer, converting that result back to a string, and then testing to see if anything changed during the process. If the result is =>true, then you know nothing changed during the conversion to an integer and therefore the string is only an Integer.
EDIT:
The example above only works if the entire string is an Integer and won’t properly deal with leading zeros. If you want to check to make sure each and every character is an Integer then do something like this instead:
pin.prepend(“1”).to_i.to_s(1..-1) == pin
Part of the question seems to be exactly HOW the following portion of code is doing its job:
pin.count("0-9")
This piece of the code is simply returning a count of how many instances of the numbers 0 through 9 exist in the string. That's only one piece of the relevant section of code though. You need to look at the rest of the line to make sense of it:
pin.count("0-9") == pin.length
The first part counts how many instances then the second part compares that to the length of the string. If they are equal (==) then that means every character in the string is an Integer.
Sometimes negation can be used to advantage:
!pin.match?(/\D/) && [4,6].include?(pin.length)
pin.match?(/\D/) returns true if the string contains a character other than a digit (matching /\D/), in which case it it would be negated to false.
One advantage of using negation here is that if the string contains a character other than a digit pin.match?(/\D/) would return true as soon as a non-digit is found, as opposed to methods that examine all the characters in the string.
I have some strings with a sentence and i need to subdivise it into a substring of maximum 40 characters.
But i don't want to split the sentence in the middle of a word.
I tried with .gsub function but it's return 40 characters maximum and avoid to cut the string in the middle of a word. But it's return only the first occurence.
sentence[0..40].gsub(/\s\w+$/,'')
I tried with split but i can select only the fist 40 characters and split in the middle of a word...
sentence.split(...){40}
My string is "Sure, we will show ourselves only when we know the east door has been opened.".
The string output i want is
["Sure, we will show ourselves only when we","know the east door has
been opened."]
Do you have a solution ? Thanks
Your first attempt:
sentence[0..40].gsub(/\s\w+$/,'')
almost works, but it has one fatal flaw. You are splitting on the number of characters before cutting off the last word. This means you have no way of knowing whether the bit being trimmed off was a whole word, or a partial word.
Because of this, your code will always cut off the last word.
I would solve the problem as follows:
sentence[/\A.{0,39}[a-z]\b/mi]
\A is an anchor to fix the regex to the start of the string.
.{0,39}[a-z] matches on 1 to 40 characters, where the last character must be a letter. This is to prevent the last selected character from being punctuation or space. (Is that desired behaviour? Your question didn't really specify. Feel free to tweak/remove that [a-z] part, e.g. [a-z.] to match a full stop, if desired.)
\b is a word boundary look-around. It is a zero-width matcher, on beginning/end of words.
/mi modifiers will include case insensitive (i.e. A-Z) and multi-line matches.
One very minor note is that because this regex is matching 1 to 40 characters (rather than zero), it is possible to get a null result. (Although this is seemingly very unlikely, since you'd need a 1-word, 41+ letter string!!) To account for this edge case, call .to_s on the result if needed.
Update: Thank you for the improved edit to your question, providing a concrete example of an input/result. This makes it much clearer what you are asking for, as the original post was somewhat ambiguous.
You could solve this with something like the following:
sentence.scan(/.{0,39}[a-z.!?,;](?:\b|$)/mi)
String#scan returns an array of strings that match the pattern - so you can then re-join these strings to reconstruct the original.
Again, I have added a few more characters (!?,;) to the list of "final characters in the substring". Feel free to tweak this as desired.
(?:\b|$) means "either a word boundary, or the end of the line". This fixes the issue of the result not including the final . in the substrings. Note that I have used a non-capture group (?:) to prevent the result of scan from changing.
Hi I've been struggling with this for the last hour and am no closer. How exactly do I strip everything except numbers, commas and decimal points from a rails string? The closest I have so far is:-
rate = rate.gsub!(/[^0-9]/i, '')
This strips everything but the numbers. When I try add commas to the expression, everything is getting stripped. I got the aboves from somewhere else and as far as I can gather:
^ = not
Everything to the left of the comma gets replaced by what's in the '' on the right
No idea what the /i does
I'm very new to gsub. Does anyone know of a good tutorial on building expressions?
Thanks
Try:
rate = rate.gsub(/[^0-9,\.]/, '')
Basically, you know the ^ means not when inside the character class brackets [] which you are using, and then you can just add the comma to the list. The decimal needs to be escaped with a backslash because in regular expressions they are a special character that means "match anything".
Also, be aware of whether you are using gsub or gsub!
gsub! has the bang, so it edits the instance of the string you're passing in, rather than returning another one.
So if using gsub! it would be:
rate.gsub!(/[^0-9,\.]/, '')
And rate would be altered.
If you do not want to alter the original variable, then you can use the version without the bang (and assign it to a different var):
cleaned_rate = rate.gsub!(/[^0-9,\.]/, '')
I'd just google for tutorials. I haven't used one. Regexes are a LOT of time and trial and error (and table-flipping).
This is a cool tool to use with a mini cheat-sheet on it for ruby that allows you to quickly edit and test your expression:
http://rubular.com/
You can just add the comma and period in the square-bracketed expression:
rate.gsub(/[^0-9,.]/, '')
You don't need the i for case-insensitivity for numbers and symbols.
There's lots of info on regular expressions, regex, etc. Maybe search for those instead of gsub.
You can use this:
rate = rate.gsub!(/[^0-9\.\,]/g,'')
Also check this out to learn more about regular expressions:
http://www.regexr.com/
I'm simply trying to convert uppercased company names into proper names.
Company names can include:
Dashes
Apostrophes
Roman Numerals
Text like LLC, LP, INC which should stay uppercase.
I thought I might be able to use acronyms like this:
ACRONYMS = %W( LP III IV VI VII VIII IX GI)
ActiveSupport::Inflector.inflections(:en) do |inflect|
ACRONYMS.each { |a| inflect.acronym(a) }
end
However, the conversion does not take into account word breaks, so having VI and VII does not work. For example, the conversion of "ADVISORS".titleize is "Ad VI Sors", as the VI becomes a whole word.
Dashes get removed.
It seems like there should be a generic gem for this generic problem, but I didn't find one. Is this problem really not that common? What's the best solution besides completely hacking the current inflection library?
Company names are a little odd, since a lot of times they're Marks (as in Service Mark) more than proper names. That means precise capitalization might actually matter, and trying to titleize might not be worth it.
In any case, here's a pattern that might work. Build your list of tokens to "keep", then manually split the string up and titleize the non-token parts.
# Make sure you put long strings before short (VII before VI)
word_tokens = %w{VII VI IX XI}
# Special characters need to be separate, since they never appear as "part" of another word
special_tokens = %w{-}
# Builds a regex like /(\bVII\b|\bVI\b|-|)/ that wraps "word tokens" in a word boundary check
token_regex = /(#{word_tokens.map{|t| /\b#{t}\b/}.join("|")}|#{special_tokens.join("|")})/
title = "ADVISORS-XI"
title.split(token_regex).map{|s| s =~ token_regex ? s : s.titleize}.join
I have user entries as filenames. Of course this is not a good idea, so I want to drop everything except [a-z], [A-Z], [0-9], _ and -.
For instance:
my§document$is°° very&interesting___thisIs%nice445.doc.pdf
should become
my_document_is_____very_interesting___thisIs_nice445_doc.pdf
and then ideally
my_document_is_very_interesting_thisIs_nice445_doc.pdf
Is there a nice and elegant way for doing this?
I'd like to suggest a solution that differs from the old one. Note that the old one uses the deprecated returning. By the way, it's anyway specific to Rails, and you didn't explicitly mention Rails in your question (only as a tag). Also, the existing solution fails to encode .doc.pdf into _doc.pdf, as you requested. And, of course, it doesn't collapse the underscores into one.
Here's my solution:
def sanitize_filename(filename)
# Split the name when finding a period which is preceded by some
# character, and is followed by some character other than a period,
# if there is no following period that is followed by something
# other than a period (yeah, confusing, I know)
fn = filename.split /(?<=.)\.(?=[^.])(?!.*\.[^.])/m
# We now have one or two parts (depending on whether we could find
# a suitable period). For each of these parts, replace any unwanted
# sequence of characters with an underscore
fn.map! { |s| s.gsub /[^a-z0-9\-]+/i, '_' }
# Finally, join the parts with a period and return the result
return fn.join '.'
end
You haven't specified all the details about the conversion. Thus, I'm making the following assumptions:
There should be at most one filename extension, which means that there should be at most one period in the filename
Trailing periods do not mark the start of an extension
Leading periods do not mark the start of an extension
Any sequence of characters beyond A–Z, a–z, 0–9 and - should be collapsed into a single _ (i.e. underscore is itself regarded as a disallowed character, and the string '$%__°#' would become '_' – rather than '___' from the parts '$%', '__' and '°#')
The complicated part of this is where I split the filename into the main part and extension. With the help of a regular expression, I'm searching for the last period, which is followed by something else than a period, so that there are no following periods matching the same criteria in the string. It must, however, be preceded by some character to make sure it's not the first character in the string.
My results from testing the function:
1.9.3p125 :006 > sanitize_filename 'my§document$is°° very&interesting___thisIs%nice445.doc.pdf'
=> "my_document_is_very_interesting_thisIs_nice445_doc.pdf"
which I think is what you requested. I hope this is nice and elegant enough.
From http://web.archive.org/web/20110529023841/http://devblog.muziboo.com/2008/06/17/attachment-fu-sanitize-filename-regex-and-unicode-gotcha/:
def sanitize_filename(filename)
returning filename.strip do |name|
# NOTE: File.basename doesn't work right with Windows paths on Unix
# get only the filename, not the whole path
name.gsub!(/^.*(\\|\/)/, '')
# Strip out the non-ascii character
name.gsub!(/[^0-9A-Za-z.\-]/, '_')
end
end
In Rails you might also be able to use ActiveStorage::Filename#sanitized:
ActiveStorage::Filename.new("foo:bar.jpg").sanitized # => "foo-bar.jpg"
ActiveStorage::Filename.new("foo/bar.jpg").sanitized # => "foo-bar.jpg"
If you use Rails you can also use String#parameterize. This is not particularly intended for that, but you will obtain a satisfying result.
"my§document$is°° very&interesting___thisIs%nice445.doc.pdf".parameterize
For Rails I found myself wanting to keep any file extensions but using parameterize for the remainder of the characters:
filename = "my§doc$is°° very&itng___thsIs%nie445.doc.pdf"
cleaned = filename.split(".").map(&:parameterize).join(".")
Implementation details and ideas see source: https://github.com/rails/rails/blob/master/activesupport/lib/active_support/inflector/transliterate.rb
def parameterize(string, separator: "-", preserve_case: false)
# Turn unwanted chars into the separator.
parameterized_string.gsub!(/[^a-z0-9\-_]+/i, separator)
#... some more stuff
end
If your goal is just to generate a filename that is "safe" to use on all operating systems (and not to remove any and all non-ASCII characters), then I would recommend the zaru gem. It doesn't do everything the original question specifies, but the filename produced should be safe to use (and still keep any filename-safe unicode characters untouched):
Zaru.sanitize! " what\ēver//wëird:user:înput:"
# => "whatēverwëirduserînput"
Zaru.sanitize! "my§docu*ment$is°° very&interes:ting___thisIs%nice445.doc.pdf"
# => "my§document$is°° very&interesting___thisIs%nice445.doc.pdf"
There is a library that may be helpful, especially if you're interested in replacing weird Unicode characters with ASCII: unidecode.
irb(main):001:0> require 'unidecoder'
=> true
irb(main):004:0> "Grzegżółka".to_ascii
=> "Grzegzolka"