I recently started learning Groovy.
I have a small task: get all lowercase words from string as List
I wrote next code:
public List<String> findWordsInLowercase(String string){
return string.findAll(/\b[a-z]+\b/)
}
It work. But i want to do it without regex, because it's very difficult to read, understand and remember.
Now i try to write same function without regex. My code:
public List<String> findWordsInLowercase(String string){
def words = string.split()
words.findAll
{it -> for(Character character in it)
character.isLowerCase()}
}
But it doesn't work :(
Rather than checking every character, why not check the word is the same as it's lowercase representation?
public List<String> findWordsInLowercase(String string) {
def words = string.split()
words.findAll { word ->
word.toLowerCase() == word
}
}
Or, it might be more understandable to make your first function:
public List<String> findWordsInLowercase(String string) {
string.findAll( /\b\p{javaLowerCase}+\b/ )
}
Which should improve readability, and you don't need to remember it, as you now have a function ;-)
You can also use meta programming to extend String class and then use this extension in normal method:
String.metaClass.isLowerCase = {
delegate ? delegate.every { it.toCharacter().isLowerCase() } : false
}
public List<String> findWordsInLowercase(String string){
string.split().findAll { it.isLowerCase() }
}
assert findWordsInLowercase('AAA bbb') == ['bbb']
Related
for my programm I want to use a TextField where the user can enter a zipcode (German ones). For that I tried what you can see below. If the user enters more than 5 digits every additional digit shall be deleted immediately. Of course letters are not allowed.
When I use this pattern ^[0-9]{0,5}$ on https://regex101.com/ it does what I intended to, but when I try this in JavaFX it doesn't work. But I couldn't find a solution yet.
Can anyone tell me what I did wrong?
Edit: For people, who didn't work with JavaFX yet: When the user enters just one character, the method check(String text) is called. So the result should also be true, when there are 1 to 5 digits. But not more ;-)
public class NumberTextField extends TextField{
ErrorLabel label;
NumberTextField(String text, ErrorLabel label){
setText(text);
setFont(Font.font("Calibri", 17));
setMinHeight(35);
setMinWidth(200);
setMaxWidth(200);
this.label = label;
}
NumberTextField(){}
#Override
public void replaceText(int start, int end, String text){
if(check(text)) {
super.replaceText(start, end, text);
}
}
#Override
public void replaceSelection(String text){
if(check(text)){
super.replaceSelection(text);
}
}
private boolean check(String text){
if(text.matches("^[0-9]{0,5}$")){
label.setText("Success");
label.setBlack();
return true;
} else{
return false;
}
}
You don't need to extend TextField to do this. In fact I recommend using a TextFormatter, since this is simpler to implement:
It does not require you to overwrite multiple method. You simply need to decide based on the data about the desired input, if you want to allow the change or not.
final Pattern pattern = Pattern.compile("\\d{0,5}");
TextFormatter<?> formatter = new TextFormatter<>(change -> {
if (pattern.matcher(change.getControlNewText()).matches()) {
// todo: remove error message/markup
return change; // allow this change to happen
} else {
// todo: add error message/markup
return null; // prevent change
}
});
TextField textField = new TextField();
textField.setTextFormatter(formatter);
Your original expression should be working fine, if we wish to validate a five-digits zip though, we might want to drop the 0 quantifier:
^[0-9]{5}$
^\d{5}$
For validation purposes, we might want to keep the start and end anchors, however for just testing, we can remove and see:
[0-9]{5}
\d{5}
It is likely that some other chars, would get through our inputs, which we do not wish to have.
Demo
Test
import java.util.regex.Matcher;
import java.util.regex.Pattern;
final String regex = "^[0-9]{5}$";
final String string = "01234\n"
+ "012345\n"
+ "0\n"
+ "1234";
final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE);
final Matcher matcher = pattern.matcher(string);
while (matcher.find()) {
System.out.println("Full match: " + matcher.group(0));
for (int i = 1; i <= matcher.groupCount(); i++) {
System.out.println("Group " + i + ": " + matcher.group(i));
}
}
This question already has answers here:
How do I create a Stream of regex matches?
(3 answers)
Closed 5 years ago.
I have created a function which return the List.
I am passing a string "(A,1),(Y,4),(F,5)" and I want to split it out based on brackets to get the 3 individual string object which are like A,1, Y,4, F,5 as 3 individual objects in a list.
I used Java 8 to create it but it return me only one value like A,1
The function is:
private List<String> getDataOnRegx(String str) {
Pattern filerRegx = Pattern.compile("\\(([a-zA-Z,0-9]*)\\s*\\),?");
Matcher regexMatcher = filerRegx.matcher(str);
return Stream.of(str).
filter(s -> regexMatcher.find() && regexMatcher.group(1) != null).
map(r -> new String(regexMatcher.group(1))).
collect(Collectors.toList());
}
The expected result I have achieved via below function where I have not used any Java 8 feature:
private List<String> getDataOnRegx(String str) {
Pattern regex = Pattern.compile("\\(([a-zA-Z,0-9]*)\\s*\\),?");
Matcher regexMatcher = regex.matcher(str);
List<String>dataList = new ArrayList<String>();
while (regexMatcher.find()) {
if (regexMatcher.group(1) != null) {
dataList.add(regexMatcher.group(1));
}
}
System.out.println(dataList);
return dataList;
}
Can somebody help me to get the all objects in a list. Just want help to correct my function which I already written using Java 8.
Strictly I have to use Java 8 compiler.
Thanks,
Atul
That's available in java-9 via Scanner#findAll:
String test = "(A,1),(Y,4),(F,5)";
Scanner sc = new Scanner(test);
Pattern filerRegx = Pattern.compile("\\(([a-zA-Z,0-9]*)\\s*\\),?");
List<String> results = sc.findAll(filerRegx)
.map(mr -> mr.group(1))
.filter(Objects::nonNull)
.collect(Collectors.toList());
System.out.println(results);
EDIT
I have no idea how that duplicate answer does not answer your question. There's like a very simple change you need to make:
static final class MatchItr extends Spliterators.AbstractSpliterator<String> {
private final Matcher matcher;
MatchItr(Matcher m) {
super(m.regionEnd() - m.regionStart(), ORDERED | NONNULL);
matcher = m;
}
#Override
public boolean tryAdvance(Consumer<? super String> action) {
if (!matcher.find()) {
return false;
}
if (matcher.group(1) == null) {
return false;
}
action.accept(matcher.group(1));
return true;
}
}
And use it:
MatchItr mIter = new MatchItr(regexMatcher);
StreamSupport.stream(mIter, false)
.forEach(System.out::println);
I've implemented the answer here to do token replacements of a string:
https://stackoverflow.com/a/1231815/1224021
My issue now is when this method finds a token with a value that is not in the dictionary. I get the exception "The given key was not present in the dictionary." and just return the normal string. What I'd like to happen obviously is all the good tokens get replaced, but the offending one remains au naturale. Guessing I'll need to do a loop vs. the one line regex replace? Using vb.net. Here's what I'm currently doing:
Shared ReadOnly re As New Regex("\$(\w+)\$", RegexOptions.Compiled)
Public Shared Function GetTokenContent(ByVal val As String) As String
Dim retval As String = val
Try
If Not String.IsNullOrEmpty(val) AndAlso val.Contains("$") Then
Dim args = GetRatesDictionary()
retval = re.Replace(val, Function(match) args(match.Groups(1).Value))
End If
Catch ex As Exception
' not sure how to handle?
End Try
Return retval
End Function
The exception is likely thrown in the line
retval = re.Replace(val, Function(match) args(match.Groups(1).Value))
because this is the only place you are keying the dictionary. Make use of the Dictionary.ContainsKey method before accessing it.
retval = re.Replace(val,
Function(match)
return If(args.ContainsKey(match.Groups(1).Value), args(match.Groups(1).Value), val)
End Function)
This is what I got to work vs. the regex, which was also a suggestion on the original thread by Allen Wang: https://stackoverflow.com/a/7957728/1224021
Public Shared Function GetTokenContent(ByVal val As String) As String
Dim retval As String = val
Try
If Not String.IsNullOrEmpty(val) AndAlso val.Contains("$") Then
Dim args = GetRatesDictionary("$")
retval = args.Aggregate(val, Function(current, value) current.Replace(value.Key, value.Value))
End If
Catch ex As Exception
End Try
Return retval
End Function
I know it's been a while since this question was answered, but FYI for anyone wanting to still use the Regex / Dictionary match approach, the following works (based on the sample in the OP question):
retVal = re.Replace(formatString,
match => args.ContainsKey(match.Groups[1].Captures[0].Value)
? args[match.Groups[1].Captures[0].Value]
: string.Empty);
... or my full sample as a string extension method is:
public static class StringExtensions
{
// Will replace parameters enclosed in double curly braces
private static readonly Lazy<Regex> ParameterReplaceRegex = new Lazy<Regex>(() => new Regex(#"\{\{(?<key>\w+)\}\}", RegexOptions.Compiled));
public static string InsertParametersIntoFormatString(this string formatString, string parametersJsonArray)
{
if (parametersJsonArray != null)
{
var deserialisedParamsDictionary = JsonConvert.DeserializeObject<Dictionary<string, string>>(parametersJsonArray);
formatString = ParameterReplaceRegex.Value.Replace(formatString,
match => deserialisedParamsDictionary.ContainsKey(match.Groups[1].Captures[0].Value)
? deserialisedParamsDictionary[match.Groups[1].Captures[0].Value]
: string.Empty);
}
return formatString;
}
}
There are a few things to note here:
1) My parameters are passed in as a JSON array, e.g.: {"ProjectCode":"12345","AnotherParam":"Hi there!"}
2) The actual template / format string to do the replacements on has the parameters enclosed in double curly braces: "This is the Project Code: {{ProjectCode}}, this is another param {{AnotherParam}}"
3) Regex is both Lazy initialized and Compiled to suit my particular use case of:
the screen this code serves may not be used often
but once it is, it will get heavy use
so it should be as efficient on subsequent calls as possible.
im trying to read a large file, so i thought that instead of looping with an array i decided to use a list, but I'm having some difficulties with searching a line which contains a word that needs to be searched for. Here is my code
public List<string> AWfile = new List<string>();
private void button1_Click(object sender, EventArgs e)
{
if (File.Exists(#"C:\DataFolder\file.txt"))
{
using (StreamReader r = new StreamReader(#"C:\DataFolder\file.txt"))
{
string line;
while ((line = r.ReadLine()) != null)
{
AWfile.Add(line); label1.Text = "ListWritten!"; label1.BackColor = Color.Green;
}
}
}
}
private void button2_Click(object sender, EventArgs e)
{
int linen = AWfile.IndexOf("A102");
label2.Text = Convert.ToString(linen);
}
So my question is if there is any way to search just for a part of a word in a list instead of the whole string, because that's the only way the .IndexOf returns me anything at all.
You can try something like:
var result = list.Select(x => x.Contains("hello")).ToList()
This will result in a list with all the elements in the list which contains "hello".
And if you want to do something only with this elements:
list.Select(x => x.Contains("hello")).ToList().ForEach(x => DoSomething(x));
I hope this helps
If I understand your question correctly... you are reading in a file and adding each line to a list. Then you want to check if any of those lines contain part of a word.
One way of doing this would be to do a foreach loop over each of the lines in your list and checking if the line contains the partial word.
Something like:
foreach(var line in AWFile)
{
if(line.Contains("PartialWordWeWant"))
{
// Do something with the line that contains the word we are looking for
}
}
I've got a wildcard pattern, perhaps "*.txt" or "POS??.dat".
I also have list of filenames in memory that I need to compare to that pattern.
How would I do that, keeping in mind I need exactly the same semantics that IO.DirectoryInfo.GetFiles(pattern) uses.
EDIT: Blindly translating this into a regex will NOT work.
I have a complete answer in code for you that's 95% like FindFiles(string).
The 5% that isn't there is the short names/long names behavior in the second note on the MSDN documentation for this function.
If you would still like to get that behavior, you'll have to complete a computation of the short name of each string you have in the input array, and then add the long name to the collection of matches if either the long or short name matches the pattern.
Here is the code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
namespace FindFilesRegEx
{
class Program
{
static void Main(string[] args)
{
string[] names = { "hello.t", "HelLo.tx", "HeLLo.txt", "HeLLo.txtsjfhs", "HeLLo.tx.sdj", "hAlLo20984.txt" };
string[] matches;
matches = FindFilesEmulator("hello.tx", names);
matches = FindFilesEmulator("H*o*.???", names);
matches = FindFilesEmulator("hello.txt", names);
matches = FindFilesEmulator("lskfjd30", names);
}
public string[] FindFilesEmulator(string pattern, string[] names)
{
List<string> matches = new List<string>();
Regex regex = FindFilesPatternToRegex.Convert(pattern);
foreach (string s in names)
{
if (regex.IsMatch(s))
{
matches.Add(s);
}
}
return matches.ToArray();
}
internal static class FindFilesPatternToRegex
{
private static Regex HasQuestionMarkRegEx = new Regex(#"\?", RegexOptions.Compiled);
private static Regex IllegalCharactersRegex = new Regex("[" + #"\/:<>|" + "\"]", RegexOptions.Compiled);
private static Regex CatchExtentionRegex = new Regex(#"^\s*.+\.([^\.]+)\s*$", RegexOptions.Compiled);
private static string NonDotCharacters = #"[^.]*";
public static Regex Convert(string pattern)
{
if (pattern == null)
{
throw new ArgumentNullException();
}
pattern = pattern.Trim();
if (pattern.Length == 0)
{
throw new ArgumentException("Pattern is empty.");
}
if(IllegalCharactersRegex.IsMatch(pattern))
{
throw new ArgumentException("Pattern contains illegal characters.");
}
bool hasExtension = CatchExtentionRegex.IsMatch(pattern);
bool matchExact = false;
if (HasQuestionMarkRegEx.IsMatch(pattern))
{
matchExact = true;
}
else if(hasExtension)
{
matchExact = CatchExtentionRegex.Match(pattern).Groups[1].Length != 3;
}
string regexString = Regex.Escape(pattern);
regexString = "^" + Regex.Replace(regexString, #"\\\*", ".*");
regexString = Regex.Replace(regexString, #"\\\?", ".");
if(!matchExact && hasExtension)
{
regexString += NonDotCharacters;
}
regexString += "$";
Regex regex = new Regex(regexString, RegexOptions.Compiled | RegexOptions.IgnoreCase);
return regex;
}
}
}
}
You can simply do this. You do not need regular expressions.
using Microsoft.VisualBasic.CompilerServices;
if (Operators.LikeString("pos123.txt", "pos?23.*", CompareMethod.Text))
{
Console.WriteLine("Filename matches pattern");
}
Or, in VB.Net,
If "pos123.txt" Like "pos?23.*" Then
Console.WriteLine("Filename matches pattern")
End If
In c# you could simulate this with an extension method. It wouldn't be exactly like VB Like, but it would be like...very cool.
You could translate the wildcards into a regular expression:
*.txt -> ^.+\.txt$
POS??.dat _> ^POS..\.dat$
Use the Regex.Escape method to escape the characters that are not wildcars into literal strings for the pattern (e.g. converting ".txt" to "\.txt").
The wildcard * translates into .+, and ? translates into .
Put ^ at the beginning of the pattern to match the beginning of the string, and $ at the end to match the end of the string.
Now you can use the Regex.IsMatch method to check if a file name matches the pattern.
Just call the Windows API function PathMatchSpecExW().
[Flags]
public enum MatchPatternFlags : uint
{
Normal = 0x00000000, // PMSF_NORMAL
Multiple = 0x00000001, // PMSF_MULTIPLE
DontStripSpaces = 0x00010000 // PMSF_DONT_STRIP_SPACES
}
class FileName
{
[DllImport("Shlwapi.dll", SetLastError = false)]
static extern int PathMatchSpecExW([MarshalAs(UnmanagedType.LPWStr)] string file,
[MarshalAs(UnmanagedType.LPWStr)] string spec,
MatchPatternFlags flags);
/*******************************************************************************
* Function: MatchPattern
*
* Description: Matches a file name against one or more file name patterns.
*
* Arguments: file - File name to check
* spec - Name pattern(s) to search foe
* flags - Flags to modify search condition (MatchPatternFlags)
*
* Return value: Returns true if name matches the pattern.
*******************************************************************************/
public static bool MatchPattern(string file, string spec, MatchPatternFlags flags)
{
if (String.IsNullOrEmpty(file))
return false;
if (String.IsNullOrEmpty(spec))
return true;
int result = PathMatchSpecExW(file, spec, flags);
return (result == 0);
}
}
Some kind of regex/glob is the way to go, but there are some subtleties; your question indicates you want identical semantics to IO.DirectoryInfo.GetFiles. That could be a challenge, because of the special cases involving 8.3 vs. long file names and the like. The whole story is on MSDN.
If you don't need an exact behavioral match, there are a couple of good SO questions:
glob pattern matching in .NET
How to implement glob in C#
For anyone who comes across this question now that it is years later, I found over at the MSDN social boards that the GetFiles() method will accept * and ? wildcard characters in the searchPattern parameter. (At least in .Net 3.5, 4.0, and 4.5)
Directory.GetFiles(string path, string searchPattern)
http://msdn.microsoft.com/en-us/library/wz42302f.aspx
Plz try the below code.
static void Main(string[] args)
{
string _wildCardPattern = "*.txt";
List<string> _fileNames = new List<string>();
_fileNames.Add("text_file.txt");
_fileNames.Add("csv_file.csv");
Console.WriteLine("\nFilenames that matches [{0}] pattern are : ", _wildCardPattern);
foreach (string _fileName in _fileNames)
{
CustomWildCardPattern _patetrn = new CustomWildCardPattern(_wildCardPattern);
if (_patetrn.IsMatch(_fileName))
{
Console.WriteLine("{0}", _fileName);
}
}
}
public class CustomWildCardPattern : Regex
{
public CustomWildCardPattern(string wildCardPattern)
: base(WildcardPatternToRegex(wildCardPattern))
{
}
public CustomWildCardPattern(string wildcardPattern, RegexOptions regexOptions)
: base(WildcardPatternToRegex(wildcardPattern), regexOptions)
{
}
private static string WildcardPatternToRegex(string wildcardPattern)
{
string patternWithWildcards = "^" + Regex.Escape(wildcardPattern).Replace("\\*", ".*");
patternWithWildcards = patternWithWildcards.Replace("\\?", ".") + "$";
return patternWithWildcards;
}
}
For searching against a specific pattern, it might be worth using File Globbing which allows you to use search patterns like you would in a .gitignore file.
See here: https://learn.microsoft.com/en-us/dotnet/core/extensions/file-globbing
This allows you to add both inclusions & exclusions to your search.
Please see below the example code snippet from the Microsoft Source above:
Matcher matcher = new Matcher();
matcher.AddIncludePatterns(new[] { "*.txt" });
IEnumerable<string> matchingFiles = matcher.GetResultsInFullPath(filepath);
The use of RegexOptions.IgnoreCase will fix it.
public class WildcardPattern : Regex {
public WildcardPattern(string wildCardPattern)
: base(ConvertPatternToRegex(wildCardPattern), RegexOptions.IgnoreCase) {
}
public WildcardPattern(string wildcardPattern, RegexOptions regexOptions)
: base(ConvertPatternToRegex(wildcardPattern), regexOptions) {
}
private static string ConvertPatternToRegex(string wildcardPattern) {
string patternWithWildcards = Regex.Escape(wildcardPattern).Replace("\\*", ".*");
patternWithWildcards = string.Concat("^", patternWithWildcards.Replace("\\?", "."), "$");
return patternWithWildcards;
}
}