View Category
Check if a string matches a regular expression
Display
"ok" if "Hello" matches /[A-Z][a-z]+/
java
if ("Hello".matches("[A-Z][a-z]+")) {
System.out.println("ok");
}
System.out.println("ok");
}
csharp
if (Regex.IsMatch("Hello", "[A-Z][a-z]+"))
{
Console.WriteLine("ok");
}
{
Console.WriteLine("ok");
}
fantom
if (Regex<|[A-Z][a-z]+|>.matches("Hello"))
echo("ok")
echo("ok")
Check if a string matches with groups
Display
"two" if "one two three" matches /one (.*) three/
java
Pattern pattern = Pattern.compile("one (.*) three");
Matcher matcher = pattern.matcher("one two three");
if (matcher.matches()) {
System.out.println(matcher.group(1));
}
Matcher matcher = pattern.matcher("one two three");
if (matcher.matches()) {
System.out.println(matcher.group(1));
}
csharp
using System;
using System.Text.RegularExpressions;
public class RegexBackReference {
public static void Main() {
var oneTwoThree = "one two three";
var pattern = "one (.*) three";
Match match = Regex.Match(oneTwoThree, pattern);
// group 0 is the entire match. 1 is the first backreference
Console.WriteLine(match.Groups[1]);
}
}
using System.Text.RegularExpressions;
public class RegexBackReference {
public static void Main() {
var oneTwoThree = "one two three";
var pattern = "one (.*) three";
Match match = Regex.Match(oneTwoThree, pattern);
// group 0 is the entire match. 1 is the first backreference
Console.WriteLine(match.Groups[1]);
}
}
fantom
m := Regex<|one (.*) three|>.matcher("one two three")
if (m.matches)
echo("${m.group(1)}")
if (m.matches)
echo("${m.group(1)}")
Check if a string contains a match to a regular expression
Display
"ok" if "abc 123 @#$" matches /\d+/
java
Pattern pattern = Pattern.compile("\\d+");
Matcher matcher = pattern.matcher(text);
if (matcher.find()) {
System.out.println("ok");
}
Matcher matcher = pattern.matcher(text);
if (matcher.find()) {
System.out.println("ok");
}
csharp
if(System.Text.RegularExpressions.Regex.IsMatch("abc 123 @#$",@"\d+")){
Console.WriteLine("ok");
}
Console.WriteLine("ok");
}
fantom
m := Regex<|\d+|>.matcher("abc 123 @#\$")
if (m.find)
echo("ok")
if (m.find)
echo("ok")
Loop through a string matching a regex and performing an action for each match
Create a list
[fish1,cow3,boat4] when matching "(fish):1 sausage (cow):3 tree (boat):4" with regex /\((\w+)\):(\d+)/
java
List list = new ArrayList();
Pattern pattern = Pattern.compile("\\((\\w+)\\):(\\d+)");
Matcher matcher = pattern.matcher(text);
while(matcher.find()) {
list.add(matcher.group(1)+matcher.group(2));
}
Pattern pattern = Pattern.compile("\\((\\w+)\\):(\\d+)");
Matcher matcher = pattern.matcher(text);
while(matcher.find()) {
list.add(matcher.group(1)+matcher.group(2));
}
csharp
using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;
public static class extensions {
public static IList<string> Map(this string me, string pattern, Func<Match, string> action){
IList<string> matches = new List<string>();
foreach (Match match in Regex.Matches(me,pattern)){
matches.Add(action(match));
}
return matches;
}
}
class Test
{
static void Main()
{
IList<string> list = "(fish):1 sausage (cow):3 tree (boat):4".Map(@"\((\w+)\):(\d+)", (m) => {return m.Groups[1].Value + m.Groups[2].Value;});
}
}
using System.Collections.Generic;
using System.Text.RegularExpressions;
public static class extensions {
public static IList<string> Map(this string me, string pattern, Func<Match, string> action){
IList<string> matches = new List<string>();
foreach (Match match in Regex.Matches(me,pattern)){
matches.Add(action(match));
}
return matches;
}
}
class Test
{
static void Main()
{
IList<string> list = "(fish):1 sausage (cow):3 tree (boat):4".Map(@"\((\w+)\):(\d+)", (m) => {return m.Groups[1].Value + m.Groups[2].Value;});
}
}
fantom
m := Regex<|\((\w+)\):(\d+)|>.matcher(s)
list := Str[,]
while (m.find) { list.add("${m.group(1)}${m.group(2)}") }
list := Str[,]
while (m.find) { list.add("${m.group(1)}${m.group(2)}") }
Replace the first regex match in a string with a static string
Transform
"Red Green Blue" into "R*d Green Blue" by replacing /e/ with "*"
java
String replaced = "Red Green Blue".replaceFirst("e", "*");
fantom
replaced := Regex<|e|>.split("Red Green Blue",2).join("*")
Replace all regex matches in a string with a static string
Transform
"She sells sea shells" into "She X X shells" by replacing /se\w+/ with "X"
java
String replaced = text.replaceAll("se\\w+", "X");
csharp
using System.Text.RegularExpressions;
class SolutionXX
{
static void Main()
{
string text = "She sells sea shells";
string result = Regex.Replace(text, @"se\w+", "X");
}
}
class SolutionXX
{
static void Main()
{
string text = "She sells sea shells";
string result = Regex.Replace(text, @"se\w+", "X");
}
}
fantom
replaced := Regex<|se\w+|>.split("She sells sea shells").join("X")
Replace all regex matches in a string with a dynamic string
Transform
"The {Quick} Brown {Fox}" into "The kciuQ Brown xoF" by reversing words in braces using the regex /\{(\w+)\}/.
java
Matcher m = Pattern.compile("\\{(\\w+)\\}").matcher("The {Quick} Brown {Fox}");
StringBuffer sb = new StringBuffer(32), rsb = new StringBuffer(8);
while (m.find())
{
rsb.replace(0, rsb.length(), m.group(1)); rsb.reverse(); m.appendReplacement(sb, rsb.toString());
}
m.appendTail(sb);
StringBuffer sb = new StringBuffer(32), rsb = new StringBuffer(8);
while (m.find())
{
rsb.replace(0, rsb.length(), m.group(1)); rsb.reverse(); m.appendReplacement(sb, rsb.toString());
}
m.appendTail(sb);
fantom
s := "The {Quick} Brown {Fox}"
m := Regex<|\{(\w+)\}|>.matcher(s)
buf := StrBuf(s.size)
last := 0
while (m.find)
{
buf.add(s[last..m.start-1]).add(m.group(1).reverse)
last = m.end
}
buf.add(s[last..-1])
replaced := buf.toStr
m := Regex<|\{(\w+)\}|>.matcher(s)
buf := StrBuf(s.size)
last := 0
while (m.find)
{
buf.add(s[last..m.start-1]).add(m.group(1).reverse)
last = m.end
}
buf.add(s[last..-1])
replaced := buf.toStr
