I have the following file name: d#cument.txt
I want to compare to see if it matches pattern: d#cument*
I do this like this:
return "d#cument.txt" Like "d#cument*"
This returns false. The ending asterix seems to be the problem. Because if I change file name to just "d#cument" and Like pattern to "d#cument" it returns true.
Any idea why and/or workaround?
Documentation states that # has a meaning in a Like pattern so you need to "escape" it by putting it between brackets :
Return "d#cument.txt" Like "d[#]cument*"
Alternatively you can use String.StartsWith to do the same thing without worrying with special chars.
Note also that though Like is convenient for simple patterns ; for things more complex it could be better to switch to Regex instead.
Related
Using Regular Extractor in JMeter, I need to get the value of "fullBkupUNIXTime" from the below response,
{"fullBackupTimeString":["Mon 10 Apr 2017 14:14:36"],"fullBkupUNIXTime":["1491833676"],"fullBackupDirName":["10_04_2017_0636"]}
I tried with Ref Name as time and
Regular Expression: "fullBkupUNIXTime": "([0-9])" and "(.+?)"
and pass them as input for 2nd request ${time}
The above 2 two doesn't work out for me.
Please Help me out of this.
First of all: why not just use this thing?
Then, if you firm with your RegExp adventure to get happen.
First expression is not going to work because you've defined it to match exactly one [0-9] charcter.
Add the appropriate repetition character, like "fullBkupUNIXTime": "([0-9]+)".
And basically it make sense to tell the engine to stop at first narrowest match too: "fullBkupUNIXTime": "([0-9]+?)"
Next, make sure you're handling space chars between key and value and colon mark properly. Better mark them explicitly, if any, with \s
And last but not least: make sure you're properly handle multiple lines (if appropriate, of course). Add the (?m) modifier to your expression.
And/or (?im) to be not case-sensitive, in addition.
[ is a reserve character in regex, you need to escape it, in your case use:
Regular Expression fullBkupUNIXTime":\["(\d+)
Template: $1$
Match No.: 1
I want to match a url field against a url prefix (which may contain percent signs), e.g. .where("url LIKE ?", "#{some_url}%").
What's the most Rails way?
From Rails version 4.2.x there is an active record method called sanitize_sql_like. So, you can do in your model a search scope like:
scope :search, -> search { where('"accounts"."name" LIKE ?', "#{sanitize_sql_like(search)}%") }
and call the scope like:
Account.search('Test_%')
The resulting escaped sql string is:
SELECT "accounts".* FROM "accounts" WHERE ("accounts"."name" LIKE 'Test\_\%%')
Read more here: http://edgeapi.rubyonrails.org/classes/ActiveRecord/Sanitization/ClassMethods.html
If I understand correctly, you're worried about "%" appearing inside some_url and rightly so; you should also be worried about embedded underscores ("_") too, they're the LIKE version of "." in a regex. I don't think there is any Rails-specific way of doing this so you're left with gsub:
.where('url like ?', some_url.gsub('%', '\\\\\%').gsub('_', '\\\\\_') + '%')
There's no need for string interpolation here either. You need to double the backslashes to escape their meaning from the database's string parser so that the LIKE parser will see simple "\%" and know to ignore the escaped percent sign.
You should check your logs to make sure the two backslashes get through. I'm getting confusing results from checking things in irb, using five (!) gets the right output but I don't see the sense in it; if anyone does see the sense in five of them, an explanatory comment would be appreciated.
UPDATE: Jason King has kindly offered a simplification for the nightmare of escaped escape characters. This lets you specify a temporary escape character so you can do things like this:
.where("url LIKE ? ESCAPE '!'", some_url.gsub(/[!%_]/) { |x| '!' + x })
I've also switched to the block form of gsub to make it a bit less nasty.
This is standard SQL92 syntax, so will work in any DB that supports that, including PostgreSQL, MySQL and SQLite.
Embedding one language inside another is always a bit of a nightmarish kludge and there's not that much you can do about it. There will always be ugly little bits that you just have to grin and bear.
https://gist.github.com/3656283
With this code,
Item.where(Item.arel_table[:name].matches("%sample!%code%"))
correctly escapes % between "sample" and "code", and matches "AAAsample%codeBBB" but does not for "AAAsampleBBBcodeCCC" on MySQL, PostgreSQL and SQLite3 at least.
Post.where('url like ?', "%#{some_url + '%'}%)
I have the following regular expression:
WHERE A.srvc_call_id = '40750564' AND REGEXP_LIKE (A.SRVC_CALL_DN, '[^TEST]')
The row that contains 40750564 has "TEST CALL" in the column SRVC_CALL_DN and REGEXP_LIKE doesn't seem to be filtering it out. Whenever I run the query it returns the row when it shouldn't.
Is my regex pattern wrong? Or does SQL not accept [^whatever]?
The carat anchors the expression to the start of a string. By enclosing the letters T, E, S & T in square brackets you're searching, as barsju suggests for any of these characters, not for the string TEST.
You say that SRVC_CALL_DN contains the string 'TEST CALL', but you don't say where in the string. You also say that you're looking for where this string doesn't match. This implies that you want to use not regexp_like(...
Putting all this together I think you need:
AND NOT REGEXP_LIKE (A.SRVC_CALL_DN, '^TEST[[:space:]]CALL')
This excludes every match from your query where the string starts with 'TEST CALL'. However, if this string may be in any position in the column you need to remove the carat - ^.
This also assumes that the string is always in upper case. If it's in mixed case or lower, then you need to change it again. Something like the following:
AND NOT REGEXP_LIKE (upper(A.SRVC_CALL_DN), '^TEST[[:space:]]CALL')
By upper-casing SRV_CALL_DN you ensure that you're always going to match but ensure that your query may not use an index on this column. I wouldn't worry about this particular point as regular expressions queries can be fairly poor at using indexes anyway and it appears as though SRVC_CALL_ID is indexed.
Also if it may not include 'CALL' you will have to remove this. It is best when using regular expressions to make your match pattern as explicit as possible; so include 'CALL' if you can.
Try with '^TEST' or '^TEST.*'
Your regexp means any string not starting with any of the characters: T,E,S,T.
But your case is so simple, starts with TEST. Why not use a simple like:
LIKE 'TEST%'
I have url, for example:
http://i.myhost.com/myimage.jpg
I want to change this url to
http://i.myhost.com/myimageD.jpg.
(Add D after image name and before point)
i.e I want add some words after image name and before point using regex.
What is the best way do it using regex?
Try using ^(.*)\.([a-zA-Z]{3,5}) and replacing with \1D\2. I'm assuming the extension is 3-5 alphanumeric numbers but you can modify it to suit. E.g. if it's just jpg images then you can put that instead of the [a-zA-Z]{3,5}.
Sounds like a homework question given the solution must use a regex, on that assumption here is an outline to get you going.
If all you have is a URL then #mathematical.coffee's solution will suit. However if you have a chunk of text within which is one or more URLs and you have to locate and change just those then you'll need something a little more involved.
Look at the structure of a URL: {protocol}{address}{item}; where
{protocol} is "http://", "ftp://" etc.;
{address} is a name, e.g. "www.google.com", or a number, e.g. "74.125.237.116" - there will always be at least one dot in the address; and
{item} is "/name" where name is quite flexible - there will be zero or more items, you can think of them as directories and a file but this isn't strictly true. Also the sequence of items can end in a "/" (including when there are zero of them).
To make a regex which matches a URL start by matching each part. In the case of the items you'll want to match the last in the sequence separately - you'll have zero or more "directories" and one "file", the latter must be of the form "name.extension".
Once you have regexes for each part you just concatenate them to produce a regex for the whole. To form the replacement pattern you can surround parts of your regex with parentheses and refer to those parts using \number in the replacement string - see #mathematical.coffee's solution for an example.
The best way to learn regexs is to use an editor which supports them and just experiment. The exact syntax may not be the same as NSRegularExpression but they are mostly pretty similar for the basic stuff and you can translate from one to another easily.
I want to match a url field against a url prefix (which may contain percent signs), e.g. .where("url LIKE ?", "#{some_url}%").
What's the most Rails way?
From Rails version 4.2.x there is an active record method called sanitize_sql_like. So, you can do in your model a search scope like:
scope :search, -> search { where('"accounts"."name" LIKE ?', "#{sanitize_sql_like(search)}%") }
and call the scope like:
Account.search('Test_%')
The resulting escaped sql string is:
SELECT "accounts".* FROM "accounts" WHERE ("accounts"."name" LIKE 'Test\_\%%')
Read more here: http://edgeapi.rubyonrails.org/classes/ActiveRecord/Sanitization/ClassMethods.html
If I understand correctly, you're worried about "%" appearing inside some_url and rightly so; you should also be worried about embedded underscores ("_") too, they're the LIKE version of "." in a regex. I don't think there is any Rails-specific way of doing this so you're left with gsub:
.where('url like ?', some_url.gsub('%', '\\\\\%').gsub('_', '\\\\\_') + '%')
There's no need for string interpolation here either. You need to double the backslashes to escape their meaning from the database's string parser so that the LIKE parser will see simple "\%" and know to ignore the escaped percent sign.
You should check your logs to make sure the two backslashes get through. I'm getting confusing results from checking things in irb, using five (!) gets the right output but I don't see the sense in it; if anyone does see the sense in five of them, an explanatory comment would be appreciated.
UPDATE: Jason King has kindly offered a simplification for the nightmare of escaped escape characters. This lets you specify a temporary escape character so you can do things like this:
.where("url LIKE ? ESCAPE '!'", some_url.gsub(/[!%_]/) { |x| '!' + x })
I've also switched to the block form of gsub to make it a bit less nasty.
This is standard SQL92 syntax, so will work in any DB that supports that, including PostgreSQL, MySQL and SQLite.
Embedding one language inside another is always a bit of a nightmarish kludge and there's not that much you can do about it. There will always be ugly little bits that you just have to grin and bear.
https://gist.github.com/3656283
With this code,
Item.where(Item.arel_table[:name].matches("%sample!%code%"))
correctly escapes % between "sample" and "code", and matches "AAAsample%codeBBB" but does not for "AAAsampleBBBcodeCCC" on MySQL, PostgreSQL and SQLite3 at least.
Post.where('url like ?', "%#{some_url + '%'}%)