I need to replace a word that starts with %.
For example Welcome to home | %brand %productName
hoping to split on words begining with % which would give me { brand, productName }.
My regex is less than average so would appreciate help with this.
Following code might help you :
string[] splits = "Welcome to home | %brand %productName".Split(' ');
List<string> lstdata = new List<string>();
for(i=0;i<splits.length;i++)
{
if(splits[i].StartsWith("%"))
lstdata.Add(splits[i].Replace('%',''));
}
Nothing wrong with string.split approach, mind you, but here's a regex approach:
string input = #"Welcome to home | %brand %productName";
string pattern = #"%\S+";
var matches = Regex.Matches(input, pattern);
string result = string.Empty;
for (int i = 0; i < matches.Count; i++)
{
result += "match " + i + ",value:" + matches[i].Value + "\n";
}
Console.WriteLine(result);
Try this:
(?<=%)\w+
This looks for any combination of word characters immediately preceded by a percent symbol.
Now, if you're doing search and replace on these matches, you'll probably want to remove the % sign as well, so you'd need to remove the lookbehind group and just have this:
%\w+
But in doing so, your replacement code would need to trim off the % sign from each match to get the word by itself.
Related
I have a large string separated by line breaks.
Example:
This is my first sentence and here i will search for the word my
This is my second sentence
Using the code below, if I search for 'my' it will only return the 2 instances of 'my' from the first sentence and not the second.
I wish to display the sentence the phrase is found in - which works fine but its just that it does not search anything after the first line break if found.
Code;
var regex = new Regex(string.Format("[^.!?;]*({0})[^.?!;]*[.?!;]", userSearchCriteraInHere, RegexOptions.Singleline));
var results = regex.Matches(largeStringInHere);
for (int i = 0; i < results.Count; i++)
{
searchCriteriaFound.Append((results[i].Value.Trim()));
searchCriteriaFound.Append(Environment.NewLine);
}
Code Edit:
string pattern = #".*(" + userSearchCriteraInHere + ")+.*";
RegexOptions options = RegexOptions.Multiline;
foreach (Match m in Regex.Matches(largeStringInHere, pattern, options))
{
searchCriteriaFound.Append(m.Value);
}
var userSearchCriteraInHere = "my";
var largeStringInHere = #"This is my first sentence and here i will search for the word my.
This is my second sentence.";
var regex = new Regex(string.Format("[^.!?;]*({0})[^.?!;]*[.?!;]", userSearchCriteraInHere), RegexOptions.Singleline);
var results = regex.Matches(largeStringInHere);
Console.WriteLine(results.Count);
var searchCriteriaFound = new StringBuilder();
for (int i = 0; i < results.Count; i++)
{
searchCriteriaFound.Append((results[i].Value.Trim()));
searchCriteriaFound.Append(Environment.NewLine);
}
Console.Write(searchCriteriaFound.ToString());
This returns the following output:
2
This is my first sentence and here i will search for the word my.
This is my second sentence.
I did need to add periods at the end of your sentences, as your regex expects them.
Is there a particular reason not to just search for the word "my" multiple times in the following way:
(my)+
You can test it over at the following URL on Regex101: https://regex101.com/r/QIHWKf/1
If you want to match the whole sentence that has "my" you can use the following:
.*(my)+.*
https://regex101.com/r/QIHWKf/2
Here your full match is the whole sentence, and your first group match is the "my".
Change
Regex(string.Format("[^.!?;]*({0})[^.?!;]*[.?!;]", userSearchCriteraInHere, RegexOptions.Singleline)
To
Regex(string.Format("[^.!?;]*({0})[^.?!;]*[.?!;]", userSearchCriteraInHere, RegexOptions.Multiline)
This changes the meaning of the symbols ^ and $ to be at the beginning/end of a line, rather than the entire string.
You could use a word boundary \b to prevent it from being part of a larger match like for example mystery and change the option to RegexOptions.Multiline instead of RegexOptions.Singleline to let ^ and $ match the end of the line.
^.*\bmy\b.*$
Regex demo
Test
To get all lines containing 'my' word, you can try this:
Code
static string GetSentencesContainMyWord(StreamReader file)
{
int counter = 0;
string line;
var sb = new StringBuilder();
while ((line = file.ReadLine()) != null)
{
if (line.Contains("my"))
sb.Append(line + Environment.NewLine);
counter++;
}
return sb.ToString();
}
If I have a string like MCCORMIC 3H R Final 08-26-2011.dwg or even MCCORMIC SMITH 2N L Final 08-26-2011.dwg and I wanted to capture the R in the first string or the L in the second string in a variable, what is the best method for doing so? I was thinking about trying the below statement but it does not work.
string filename = "MCCORMIC 3H R Final 08-26-2011.dwg"
string WhichArea = "";
int WhichIndex = 0;
WhichIndex = filename.IndexOf("Final");
WhichArea = filename.Substring(WhichIndex - 1,1); //Trying to get the R in front of word Final
Just split by space:
var parts = filename.Split(new [] {' '},
StringSplitOptions.RemoveEmptyEntries);
WhichArea = parts[parts.Length - 3];
It looks like the file names have a very specific format, so this will work just fine.
Even with any number of spaces, using StringSplitOptions.RemoveEmptyEntries means spaces will not be part of the split result set.
Code updated to deal with both examples - thanks Nikola.
I had to do something similar, but with Mirostation drawings instead of Autocad. I used regex in my case. Here's what I did, just in case you feel like making it more complex.
string filename = "MCCORMIC 3H R Final 08-26-2011.dwg";
string filename2 = "MCCORMIC SMITH 2N L Final 08-26-2011.dwg";
Console.WriteLine(TheMatch(filename));
Console.WriteLine(TheMatch(filename2));
public string TheMatch(string filename) {
Regex reg = new Regex(#"[A-Za-z0-9]*\s*([A-Z])\s*Final .*\.dwg");
Match match = reg.Match(filename);
if(match.Success) {
return match.Groups[1].Value;
}
return String.Empty;
}
I don't think Oded's answer covers all cases. The first example has two words before the wanted letter, and the second one has three words before it.
My opinion is that the best way to get this letter is by using RegEx, assuming that the word Final always comes after the letter itself, separated by any number of spaces.
Here's the RegEx code:
using System.Text.RegularExpressions;
private string GetLetter(string fileName)
{
string pattern = "\S(?=\s*?Final)";
Match match = Regex.Match(fileName, pattern);
return match.Value;
}
And here's the explanation of RegEx pattern:
\S(?=\s*?Final)
\S // Anything other than whitespace
(?=\s*?Final) // Positive look-ahead
\s*? // Whitespace, unlimited number of repetitions, as few as possible.
Final // Exact text.
I have a string "Page 1 of 15".
I need to get the value 15 as this value could be any number between 1 and 100. I'm trying to figure out:
If regular expressions are best suited here. Considering string will never change maybe just split the string by spaces? Or a better solution.
How to get the value using a regular expression.
Regular expression you can use: Page \d+ of (\d+)
Regex re = new Regex(#"Page \d+ of (\d+)");
string input = "Page 1 of 15";
Match match = re.Match(input);
string pages = match.Groups[1].Value;
Analysis of expression: between ( and ) you capture a group. The \d stands for digit, the + for one or more digits. Note that it is important to be exact, so copy the spaces as well.
The code is a tad verbose, but I figured it'd be better understandable this way. With a split you just need: var pages = input.Split(' ')[3];, looks easier, but is error-prone. The regex is easily extended to grab other parts of the string in one go.
var myString = "Page 1 of 15";
var number = myString.SubString(myString.LastIndexOf(' ') + 1);
If there is a risk of whitespace at the end of the string then apply a TrimEnd method:
var number = myString.SubString(myString.TrimEnd().LastIndexOf(' ') + 1);
I think a simple String.Replace() is the best, most readable solution for something so simple.
string myString = "Page 1 of 15";
string pageNumber = myString.Replace("Page 1 of ", "");
EDIT:
The above solution assumes that the string will never be Page 2 of 15. If the first page number can change, you'll need to use String.Split() instead.
string myString = "Page 1 of 15";
string pageNumber = myString.Split(new string[] {"of"},
StringSplitOptions.None).Last().Trim();
if the string format will never change then you can try this...
string input = "Page 1 of 15";
string[] splits = input.Split(' ');
int totalPages = int.Parse(splits[splits.Length - 1]);
If this is the only case you will ever have to handle, just split the string by spaces and use the parse the 4th part to an integer. Something like that will work:
string input = "Page 1 of 15";
string[] splitInput = string.Split(' ');
int numberOfPages = int.Parse(splitInput[3]);
In c# it should looks like this (using Regex class):
Regex r = new Regex(#"Page \d+ of (\d+)");
var str = "Page 1 of 15";
var mathes = r.Matches(str);
Your resoult will be in: mathes[0].Groups[1]
You dont need a regex for this. Just the the index of the last space
string var = "1 of100";
string secondvar = string.Empty;
int startindex = var.LastIndexOf(" ");
if (startindex > -1)
{
secondvar = var.Substring(startindex +1);
}
I want to match following pattern:
key="value" key="value" key="value" key="value" ...
where key and value are [a-z0-9]+, both should be grouped (2 groups, the " - chars can be matched or skipped)
input that should not be matched:
key="value"key="value" (no space between pairs)
For now I got this(not .NET syntax):
([a-z0-9]+)=(\"[a-z0-9]+\")(?=\s|$)
the problem with that, that it matches key4="value4" in input:
key3="value3"key4="value4"
The spec isn't very clear, but you can try:
(?<!\S)([a-z0-9]+)=("[a-z0-9]+")(?!\S)
Or, as a C# string literal:
"(?<!\\S)([a-z0-9]+)=(\"[a-z0-9]+\")(?!\\S)"
This uses a negative lookarounds to ensure that the the key-value pair is neither preceded nor followed by non-whitespace characters.
Here's an example snippet (as seen on ideone.com):
var input = "key1=\"value1\" key2=\"value2\"key3=\"value3\" key4=\"value4\"";
Console.WriteLine(input);
// key1="value1" key2="value2"key3="value3" key4="value4"
Regex r = new Regex("(?<!\\S)([a-z0-9]+)=(\"[a-z0-9]+\")(?!\\S)");
foreach (Match m in r.Matches(input)) {
Console.WriteLine(m);
}
// key1="value1"
// key4="value4"
Related questions
How does the regular expression (?<=#)[^#]+(?=#) work?
On validating the entire input
You can use Regex.IsMatch to see if the input string matches against what should be the correct input pattern. You can also use the same pattern to extract the keys/values, thanks to the fact that .NET regex lets you access individual captures.
string[] inputs = {
"k1=\"v1\" k2=\"v2\" k3=\"v3\" k4=\"v4\"",
"k1=\"v1\" k2=\"v2\"k3=\"v3\" k4=\"v4\"",
" k1=\"v1\" k2=\"v2\" k3=\"v3\" k4=\"v4\" ",
" ",
" what is this? "
};
Regex r = new Regex("^\\s*(?:([a-z0-9]+)=\"([a-z0-9]+)\"(?:\\s+|$))+$");
foreach (string input in inputs) {
Console.Write(input);
if (r.IsMatch(input)) {
Console.WriteLine(": MATCH!");
Match m = r.Match(input);
CaptureCollection keys = m.Groups[1].Captures;
CaptureCollection values = m.Groups[2].Captures;
int N = keys.Count;
for (int i = 0; i < N; i++) {
Console.WriteLine(i + "[" + keys[i] + "]=>[" + values[i] + "]");
}
} else {
Console.WriteLine(": NO MATCH!");
}
}
The above prints (as seen on ideone.com):
k1="v1" k2="v2" k3="v3" k4="v4": MATCH!
0[k1]=>[v1]
1[k2]=>[v2]
2[k3]=>[v3]
3[k4]=>[v4]
k1="v1" k2="v2"k3="v3" k4="v4": NO MATCH!
k1="v1" k2="v2" k3="v3" k4="v4" : MATCH!
0[k1]=>[v1]
1[k2]=>[v2]
2[k3]=>[v3]
3[k4]=>[v4]
: NO MATCH!
what is this? : NO MATCH!
References
Is there a regex flavor that allows me to count the number of repetitions matched by the * and + operators?
Explanation of the pattern
The pattern to validate the entire input is essentially:
maybe leading
spaces ___ end of string anchor
| /
^\s*(entry)+$
| \
beginning \__ one or more entry
of string
anchor
Where each entry is:
key=value(\s+|$)
That is, a key/value pair followed by either spaces or the end of the string.
I think SilentGhost proposal is about using String.Split()
Like this :
String keyValues = "...";
foreach(String keyValuePair in keyValues.Split(' '))
Console.WriteLine(keyValuePair);
This is definitively faster and simpler.
Use a lookbehind like you used your lookahead:
(?<=\s|^)([a-z0-9]+)=(\"[a-z0-9]+\")(?=\s|$)
I second Jens' answer (but am still too puny to comment on others' answers).
Also, I've found this Regular Expressions Reference site to be quite awesome. There's a section on Lookaround about halfway down on the Advanced page, and some further notes about Lookbehind.
I'm just beginning to use Regex so bear with my terminology. I have a regex pattern that is working properly on a string. The string could be in the format "text [pattern] text". Therefore, I also have a regex pattern that negates the first pattern. If I print out the results from each of the matches everything is shown correctly.
The problem I'm having is I want to add text into the string and it changes the index of matches in a regex MatchCollection. For example, if I wanted to enclose the found match in "td" match "/td"" tags I have the following code:
Regex r = new Regex(negRegexPattern, RegexOptions.IgnoreCase | RegexOptions.Singleline);
MatchCollection mc = r.Matches(text);
if (mc.Count > 0)
{
for (int i = 0; i < mc.Count; i++)
{
text = text.Remove(mc[i].Index, mc[i].Length);
text = text.Insert(mc[i].Index, "<td>" + mc[i].Value + "</td>");
}
}
This works great for the first match. But as you'd expect the mc[i].Index is no longer valid because the string has changed. Therefore, I tried to search for just a single match in the for loop for the amount of matches I would expect (mc.Count), but then I keep finding the first match.
So hopefully without introducing more regex to make sure it's not the first match and with keeping everything in one string, does anybody have any input on how I could accomplish this? Thanks for your input.
Edit: Thank you all for your responses, I appreciate all of them.
It can be as simple as:-
string newString = Regex.Replace("abc", "b", "<td>${0}</td>");
Results in a<td>b</td>c.
In your case:-
Regex r = new Regex(negRegexPattern, RegexOptions.IgnoreCase | RegexOptions.Singleline);
text = r.Replace(text, "<td>${0}</td>");
Will replace all occurance of negRegexPattern with the content of that match surrounded by the td element.
Although I agree that the Regex.Replace answer above is the best choice, just to answer the question you asked, how about replacing from the last match to the first. This way your string grows beyond the "previous" match so the earlier matches indexes will still be valid.
for (int i = mc.Count - 1; i > 0; --i)
static string Tabulate(Match m)
{
return "<td>" + m.ToString() + "</td>";
}
static void Replace()
{
string text = "your text";
string result = Regex.Replace(text, "your_regexp", new MatchEvaluator(Tabulate));
}
You can try something like this:
Regex.Replace(input, pattern, match =>
{
return "<tr>" + match.Value + "</tr>";
});
Keep a counter before the loop starts, and add the amount of characters you inserted every time. IE:
Regex r = new Regex(negRegexPattern, RegexOptions.IgnoreCase | RegexOptions.Singleline);
MatchCollection mc = r.Matches(text);
int counter = 0;
for (int i = 0; i < mc.Count; i++)
{
text = text.Remove(mc[i].Index + counter, mc[i].Length);
text = text.Insert(mc[i].Index + counter, "<td>" + mc[i].Value + "</td>");
counter += ("<td>" + "</td>").Length;
}
I haven't tested this, but it SHOULD work.