I would like to check if a string includes all of the given regexs. I dont want to go through the string for each regex.
return "foo".all_chars {include? ( \letter\ && \number\ && \special\)}
or
return "foo".all_chars {include? ( \letter , number , special\)}
I dont want to go through the string for each regex.
You'd end up with a really nasty, unreadable, and unmaintainable regex pattern. But if you want to you could combine them, and then just call match? on it.
Given...
regex1 = %r{[a-z]}
regex2 = %r{[^aeiou]}
all_regex = %r{[a-z&&[^aeiou]]}
But here's really no harm in using Enumerable#all?
[regex1, regex2, regex3].all? { |regex| string.match?(regex) }
Related
I have a large file in a ruby variable, it follows a common pattern like so:
// ...
// comment
$myuser['bla'] = 'bla';
// comment
$myuser['bla2'] = 'bla2';
// ...
I am trying to given a 'key' replace the 'value'
This replaces the entire string how do I fix it? Another method I thought is to do it in two steps, step one would be to find the value within the quotes then to perform a string replace, what's best?
def keyvalr(content, key, value)
return content.gsub(/\$bla\[\'#{key}\'\]\s+\=\s+\'(.*)\'/) {|m| value }
end
The .* is greedy and consumes as much as possible (everything until the very last '). Make that . a [^'] then it is impossible for it to go past the first closing '.
/(\$bla\[\'#{key}\'\]\s+\=\s+\')[^']*(\')/
I also added parentheses to capture everything except for the value, which is to be replaced. The first set of parens will correspond to \1 and the second to \2. So that you replace the match of this with:
"\1yournewvaluehere\2"
I'd use something like:
text = %q{
// ...
// comment
$myuser['bla'] = 'bla';
// comment
$myuser['bla2'] = 'bla2';
// ...
}
from_to = {
'bla' => 'foo',
'bla2' => 'bar'
}
puts text.gsub(/\['([^']+)'\] = '([^']+)'/) { |t|
key, val = t.scan(/'([^']+)'/).flatten
"['%s'] = '%s'" % [ key, from_to[key] ]
}
Which outputs:
// ...
// comment
$myuser['bla'] = 'foo';
// comment
$myuser['bla2'] = 'bar';
// ...
This is how it works:
If I do:
puts text.gsub(/\['([^']+)'\] = '([^']+)'/) { |t|
puts t
}
I see:
['bla'] = 'bla'
['bla2'] = 'bla2'
Then I tried:
"['bla'] = 'bla'".scan(/'([^']+)'/).flatten
=> ["bla", "bla"]
That gave me a key, "value" pair, so I could use a hash to look-up the replacement value.
Sticking it inside a gsub block meant whatever matched got replaced by my return value for the block, so I created a string to replace the "hit" and let gsub do its "thang".
I'm not a big believer in using long regex. I've had to maintain too much code that tried to use complex patterns, and got something wrong, and failed to accomplish what was intended 100% of the time. They're very powerful, but maintenance of code is a lot harder/worse than developing it, so I try to keep patterns I write in spoon-size pieces, having mercy on those who follow me in maintaining the code.
I have a list of Mobile devices that I'm using to display content correctly. The depreciated function looks like this:
function detectPDA($query){
$browserAgent = $_SERVER['HTTP_USER_AGENT'];
$userAgents = $this->getBrowserAgentsToDetect(); // comma separated list of devices
foreach ( $userAgents as $userAgent ) {
if(eregi($userAgent,$browserAgent)){
if(eregi("iphone",$browserAgent) || eregi("ipod",$browserAgent) ){
$this->iphone = true;
}else{
$this->pda = true;
}
}
}
}
What is the correct way to replace the eregi functions?
If all the pattern strings ($userAgent and iphone) can be trusted not to contain special regex chars (()[]!|.^${}?*+), then you just surround the eregi regex with slashes (/) and add an i after the last slash (which means "case insensitive").
So:
eregi($userAgent,$browserAgent) --> preg_match("/$userAgent/i",$browserAgent)
eregi("iphone",$browserAgent) --> preg_match('/iphone/i',$browserAgent)
However, are you just trying to match $userAgent as-is within $browserAgent? For example, if a particular $userAgent was foo.bar, would you want the . to match a literal period, or would you want to interpret it in its regex sense ("match any character")?
If the former, I'd suggest you forgo regex entirely and use stripos($haystack,$needle), which searches for the string $needle in $haystack (case-insensitive). Then you don't need to worry about (say) an asterisk in $userAgent being interpreted in the regex sense instead of the literal sense.
If you do use stripos don't forget it can return a 0 which would evaluate to false, so you need to use === false or !== false (see the documentation I linked).
I've got a regular expression that I am using to strip an extension from another string
The extensions in this example are
BK|BZ|113
If the string does not contain any of the extensions, then I need it to leave the string as is.
The regular expression I'm using is
base_value = base_string[/(.*?[^-])-?(?:BK|BZ|113)/,1]
However, if the base_value does not contain the string, I want to return the base_value. I thought I could use
base_value = base_string
base_value = base_string[/(.*?[^-])-?(?:BK|BZ|113)/,1] unless (base_value !~ /(.*?[^-])-?(?:BK|BZ|113)) == false
but that isn't working.
What is the best way to return the base_string if the extensions are not found?
If I understand well, you want to strip the regexp from a string, if it matches, right? So.. do it:
string.sub(/(?:BK|BZ|113)$/, "")
Perhaps you can use sub like this:
base_string1 = "test1BK"
base_string2 = "test2"
p base_string1.sub(/(.*?[^-])-?(?:BK|BZ|113)/,'\1')
p base_string2.sub(/(.*?[^-])-?(?:BK|BZ|113)/,'\1')
When the pattern is not found nothing is replaced, otherwise it returns the string without the extension.
If /(.*?[^-])-?(?:BK|BZ|113)/ doesn't match then base_string[/(.*?[^-])-?(?:BK|BZ|113)/,1] will be nil. So this should work:
base_value = base_string[/(.*?[^-])-?(?:BK|BZ|113)/,1] || base_string
How would I go about testing for an exact match using regex.
"car".match(/[ca]+/) returns true.
How would I get the above statement to return false since the regex pattern doesn't contain an "r"? Any string that contains any characters other than "c" and "a" should return false.
"acacaccc" should return true
"acacacxcc" should return false
Add some anchors to it:
/^[ca]+$/
You just need anchors.
"car".match(/^[ca]+$/)
This'll force the entire string to be composed of "c" or "a", since the "^" and "$" mean "start" and "end" of the string. Without them, the regex will succeed as long as it matches any portion of the string.
Turn your logic around and look for bad things:
string.match(/[^ca]/)
string.index(/[^ca]/)
If either of the above are non-nil, then you have a bad string. If you just want to test and don't care about where it matches then:
if string.index(/[^ca]/).nil?
# You have a good string
else
# You have a bad string
For example:
>> "car".index(/[^ca]/).nil?
=> false
>> "caaaacaac".index(/[^ca]/).nil?
=> true
try this
"car".match /^(a|c)+$/
Try this:
"car".match(/^(?:c|a)$/)
In Ruby, what regex will strip out all but a desired string if present in the containing string? I know about /[^abc]/ for characters, but what about strings?
Say I have the string "group=4&type_ids[]=2&type_ids[]=7&saved=1" and want to retain the pattern group=\d, if it is present in the string using only a regex?
Currently, I am splitting on & and then doing a select with matching condition =~ /group=\d/ on the resulting enumerable collection. It works fine, but I'd like to know the regex to do this more directly.
Simply:
part = str[/group=\d+/]
If you want only the numbers, then:
group_str = str[/group=(\d+)/,1]
If you want only the numbers as an integer, then:
group_num = str[/group=(\d+)/,1].to_i
Warning: String#[] will return nil if no match occurs, and blindly calling nil.to_i always returns 0.
You can try:
$str =~ s/.*(group=\d+).*/\1/;
Typically I wouldn't really worry too much about a complex regex. Simply break the string down into smaller parts and it becomes easier:
asdf = "group=4&type_ids[]=2&type_ids[]=7&saved=1"
asdf.split('&').select{ |q| q['group'] } # => ["group=4"]
Otherwise, you can use regex a bunch of different ways. Here's two ways I tend to use:
asdf.scan(/group=\d+/) # => ["group=4"]
asdf[/(group=\d+)/, 1] # => "group=4"
Try:
str.match(/group=\d+/)[0]