I am learning regexp.my regexp is:
/^([0-5][0-9]|60):/g
My sample data is: 60:40:60 Lua
Everything is fine. Now I want to extract first occurrence before :. i.e: 60 but when I try to using $1. it return 6040. Any idea?
What about that one:
^(?:[0-5][0-9]|60)(?=:)
Demo
Or in your way with validation, you may try that:
^(?:[0-5][0-9]|60)(?=:\d{2}:\d{2}.*)
Explanation:
^(?:[0-5][0-9]|60) - Same as yours
(?=:\d{2}:\d{2}.*) -- positive lookahead to ensure that the previous pattern is followed by 2 digit colon 2 digt and followed by rest of the string of zero or more length.
Demo 2
As it seems like it is not serving according to your need there is a solution that captures 3 groups where group 1 starts with the digits you desire:
const regex = /^([0-5][0-9]|60):([0-5][0-9]|60):([0-5][0-9]|60).*$/gm;
const str = `60:40:60 Lua`;
let m;
if ((m = regex.exec(str)) !== null) {
console.log(m[1]);
console.log(m[2]);
console.log(m[3]);
}
Related
I have a string that looks like the following:
<#399969178745962506> hello to <#!104729417217032192>
I have a dictionary containing both that looks like following:
{"399969178745962506", "One"},
{"104729417217032192", "Two"}
My goal here is to replace the <#399969178745962506> into the value of that number key, which in this case would be One
Regex.Replace(arg.Content, "(?<=<)(.*?)(?=>)", m => userDic.ContainsKey(m.Value) ? userDic[m.Value] : m.Value);
My current regex is as following: (?<=<)(.*?)(?=>) which only matches everything in between < and > which would in this case leave both #399969178745962506 and #!104729417217032192
I can't just ignore the # sign, because the ! sign is not there every time. So it could be optimal to only get numbers with something like \d+
I need to figure out how to only get the numbers between < and > but I can't for the life of me figure out how.
Very grateful for any help!
In C#, you may use 2 approaches: a lookaround based on (since lookbehind patterns can be variable width) and a capturing group approach.
Lookaround based approach
The pattern that will easily help you get the digits in the right context is
(?<=<#!?)\d+(?=>)
See the regex demo
The (?<=<#!?) is a positive lookbehind that requires <= or <=! immediately to the left of the current location and (?=>) is a positive lookahead that requires > char immediately to the right of the current location.
Capturing approach
You may use the following pattern that will capture the digits inside the expected <...> substrings:
<#!?(\d+)>
Details
<# - a literal <# substring
!? - an optional exclamation sign
(\d+) - capturing group 1 that matches one or more digits
> - a literal > sign.
Note that the values you need can be accessed via match.Groups[1].Value as shown in the snippet above.
Usage:
var userDic = new Dictionary<string, string> {
{"399969178745962506", "One"},
{"104729417217032192", "Two"}
};
var p = #"<#!?(\d+)>";
var s = "<#399969178745962506> hello to <#!104729417217032192>";
Console.WriteLine(
Regex.Replace(s, p, m => userDic.ContainsKey(m.Groups[1].Value) ?
userDic[m.Groups[1].Value] : m.Value
)
); // => One hello to Two
// Or, if you need to keep <#, <#! and >
Console.WriteLine(
Regex.Replace(s, #"(<#!?)(\d+)>", m => userDic.ContainsKey(m.Groups[2].Value) ?
$"{m.Groups[1].Value}{userDic[m.Groups[2].Value]}>" : m.Value
)
); // => <#One> hello to <#!Two>
See the C# demo.
To extract just the numbers from you're given format, use this regex pattern:
(?<=<#|<#!)(\d+)(?=>)
See it work in action: https://regexr.com/3j6ia
You can use non-capturing groups to exclude parts of the needed pattern to be inside the group:
(?<=<)(?:#?!?)(.*?)(?=>)
alternativly you could name the inner group and use the named group to get it:
(?<=<)(?:#?!?)(?<yourgroupname>.*?)(?=>)
Access it via m.Groups["yourgroupname"].Value - more see f.e. How do I access named capturing groups in a .NET Regex?
Regex: (?:<#!?(\d+)>)
Details:
(?:) Non-capturing group
<# matches the characters <# literally
? Matches between zero and one times
(\d+) 1st Capturing Group \d+ matches a digit (equal to [0-9])
Regex demo
string text = "<#399969178745962506> hello to <#!104729417217032192>";
Dictionary<string, string> list = new Dictionary<string, string>() { { "399969178745962506", "One" }, { "104729417217032192", "Two" } };
text = Regex.Replace(text, #"(?:<#!?(\d+)>)", m => list.ContainsKey(m.Groups[1].Value) ? list[m.Groups[1].Value] : m.Value);
Console.WriteLine(text); \\ One hello to Two
Console.ReadLine();
I need to combine some text using regex, but I'm having a bit of trouble when trying to capture and substitute my string. For example - I need to capture digits from the start, and add them in a substitution to every section closed between ||
I have:
||10||a||ab||abc||
I want:
||10||a10||ab10||abc10||
So I need '10' in capture group 1 and 'a|ab|abc' in capture group 2
I've tried something like this, but it doesn't work for me (captures only one [a-z] group)
(?=.*\|\|(\d+)\|\|)(?=.*\b([a-z]+\b))
I would achieve this without a complex regular expression. For example, you could do this:
input = "||10||a||ab||abc||"
parts = input.scan(/\w+/) # => ["10", "a", "ab", "abc"]
parts[1..-1].each { |part| part << parts[0] } # => ["a10", "ab10", "abc10"]
"||#{parts.join('||')}||"
str = "||10||a||ab||abc||"
first = nil
str.gsub(/(?<=\|\|)[^\|]+/) { |s| first.nil? ? (first = s) : s + first }
#=> "||10||a10||ab10||abc10||"
The regular expression reads, "match one or more characters in a pipe immediately following two pipes" ((?<=\|\|) being a positive lookbehind).
I have a String which contains column names and datatypes as below:
val cdt = "header:integer|releaseNumber:numeric|amountCredit:numeric|lastUpdatedBy:numeric(15,10)|orderNumber:numeric(20,0)"
My requirement is to convert the postgres datatypes which are present as numeric, numeric(15,10) into spark-sql compatible datatypes.
In this case,
numeric -> decimal(38,30)
numeric(15,10) -> decimal(15,10)
numeric(20,0) -> bigint (This is an integeral datatype as there its precision is zero.)
In order to access the datatype in the string: cdt, I split it and created a Seq from it.
val dt = cdt.split("\\|").toSeq
Now I have a Seq of elements in which each element is a String in the below format:
Seq("header:integer", "releaseNumber:numeric","amountCredit:numeric","lastUpdatedBy:numeric(15,10)","orderNumber:numeric(20,0)")
I have the pattern matching regex: """numeric\(\d+,(\d+)\)""".r, for numeric(precision, scale) which only works if there is a
scale of two digits, ex: numeric(20,23).
I am very new to REGEX and Scala & I don't understand how to create regex pattterns for the remaining two cases & apply it on a string to match a condition. I tried it in the below way but it gives me a compilation error: "Cannot resolve symbol findFirstMatchIn"
dt.map(e => e.split("\\:")).map(e => changeDataType(e(0), e(1)))
def changeDataType(colName: String, cd:String): String = {
val finalColumns = new String
val pattern1 = """numeric\(\d+,(\d+)\)""".r
cd match {
case pattern1.findFirstMatchIn(dt) =>
}
}
I am trying to get the final output into a String as below:
header:integer|releaseNumber:decimal(38,30)|amountCredit:decimal(38,30)|lastUpdatedBy:decimal(15,10)|orderNumber:bigint
How to multiple regex patterns for different cases to check/apply pattern matching on datatype of each value in the seq and change it to my suitable datatype as mentioned above.
Could anyone let me know how can I achieve it ?
It can be done with a single regex pattern, but some testing of the match results is required.
val numericRE = raw"([^:]+):numeric(?:\((\d+),(\d+)\))?".r
cdt.split("\\|")
.map{
case numericRE(col,a,b) =>
if (Option(b).isEmpty) s"$col:decimal(38,30)"
else if (b == "0") s"$col:bigint"
else s"$col:decimal($a,$b)"
case x => x //pass-through
}.mkString("|")
//res0: String = header:integer|releaseNumber:decimal(38,30)|amountCredit:decimal(38,30)|lastUpdatedBy:decimal(15,10)|orderNumber:bigint
Of course it can be done with three different regex patterns, but I think this is pretty clear.
explanation
raw - don't need so many escape characters - \
([^:]+) - capture everything up to the 1st colon
:numeric - followed by the string ":numeric"
(?: - start a non-capture group
\((\d+),(\d+)\) - capture the 2 digit strings, separated by a comma, inside parentheses
)? - the non-capture group is optional
numericRE(col,a,b) - col is the 1st capture group, a and b are the digit captures, but they are inside the optional non-capture group so they might be null
I am trying to capture the bold part of strings like this:
'capture a year range at the end of a string 1995-2010'
'if there's no year range just capture the single year 2005'
'capture a year/year range followed by a parenthesis, including the parenthesis 2007-2012 (58 months)'
This regex works for 1 and 2, but I can't get it to work for 3:
/(\d+([-–— ]\d+( \(\d+ months\))?)?$)/
What am I doing wrong?
Try this regex:
/\d{4}(?:[-–— ]\d{4})?(?:\s*\([^)]+\))?$/gm
This one captures everything in the brackets.
If you need a regex specific to the text "(number) months" in the brackets, then you can use this: \d{4}(?:[-–— ]\d{4})?(?:\s+\(\d+\smonths\))?$
Link to test: RegexPal or RegExr
Sample text:
capture a year range at the end of a string 1995-2010
if there's no year range just capture the single year 2005
capture a year/year range followed by a parenthesis, including the
parenthesis 2007-2012 (58 months)
trying out another example 1990 (23 weeks)
trying out another example 1995-2002 (x days)
trying out another example 2050 (blah blah)
trying out another example 2050—3000
trying out another example 2050-3000
trying out another example 2050–3000
And the JavaScript code:
var regex = /\d{4}(?:[-–— ]\d{4})?(?:\s*\([^)]+\))?$/gm; //multiline enabled
var input = "your input string";
if(regex.test(input)) {
var matches = input.match(regex);
for(var match in matches) {
alert(matches[match]);
}
} else {
alert("No matches found!");
}
This Regex works nicely. :)
/(?:(?:\d{4}[-–— ])?\d{4})(?: \(\d+ months\))?$/
The main difference between my Regex and Jonah's is that mine contains ?: which means not to capture the sub-groups. When you group in a Regex it automatically returns what is in that group unless you tell it not to, and I've found that sometimes when those groups get captured when using methods such as replace or split, that it can be a little buggy which may be your problem as well.
The following regex works for me in a sample Perl script. It should be workable in JavaScript:
/(\d{4}([-–— ]\d{4})?( \(\d+ months\))?)$/
We first match a 4-digit year: \d{4}
Then we match an optional separator followed by another 4-digit year: ([-–— ]\d{4})?
Finally, we match the optional months portion: ( \(\d+ months\))?
You may need to insert whitespace matches (\s*) where needed, if your data doesn't always follow this strict template.
It actually works fine here, if I understand your needs correctly: Gskinner RegExr
Just alternate which sentence is the last, as $ will not count for newlines, just the end of the string.
I have the following string:
123322
In theory, the regex 1.*2 should match the following:
12 (because * can be zero characters)
12332
123322
If I use the regex 1.*2 it matches 123322.
Using 1.*?2, it will match 12.
Is there a way to match 12332 too?
The perfect thing would be to get all possible matchess in the string (no matter if one match is substring of another)
No, unless there is something else added to the regex to clarify what it should do it will either be greedy or non-greedy. There is no in-betweeny ;)
1(.*?2)*$
you will have multiple captures which you can concatenate to form all possible matches
see here:regex tester
click on 'table' and expand the captures tree
You would need a separate expression for each case, depending on the number of twos you want to match:
1(.*?2){1} #same as 1.*?2
1(.*?2){2}
1(.*?2){3}
...
Generally, this isn't possible. A regex matching engine isn't really designed to find overlapping matches. A quick solution is simply to check the pattern on all substrings manually:
string text = "1123322";
for (int start = 0; start < text.Length - 1; start++)
{
for (int length = 0; length <= text.Length - start; length++)
{
string subString = text.Substring(start, length);
if (Regex.IsMatch(subString, "^1.*2$"))
Console.WriteLine("{0}-{1}: {2}", start, start + length, subString);
}
}
Working example: http://ideone.com/aNKnJ
Now, is it possible to get a whole-regex solution? Mostly, the answer is no. However, .Net does has a few tricks in its sleeve to help us: it allows variable length lookbehind, and allows each capturing group to remember all captures (most engines only return the last match of each group). Abusing these, we can simulate the same for loop inside the regex engine:
string text = "1123322!";
string allMatchesPattern = #"
(?<=^ # Starting at the local end position, look all the way to the back
(
(?=(?<Here>1.*2\G))? # on each position from the start until here (\G),
. # *try* to match our pattern and capture it,
)* # but advance even if you fail to match it.
)
";
MatchCollection matches = Regex.Matches(text, allMatchesPattern,
RegexOptions.ExplicitCapture | RegexOptions.IgnorePatternWhitespace);
foreach (Match endPosition in matches)
{
foreach (Capture startPosition in endPosition.Groups["Here"].Captures)
{
Console.WriteLine("{0}-{1}: {2}", startPosition.Index,
endPosition.Index - 1, startPosition.Value);
}
}
Note that currently there's a small bug there - the engine doesn't try to match the last ending position ($), so you loose a few matches. For now, adding a ! at the end of the string solves that issue.
working example: http://ideone.com/eB8Hb