Problem: I want to write a method that takes a message/index pair like this:
("Hello, I am *Name1, how are you doing *Name2?", 2)
The index refers to the asterisk delimited name in the message. So if the index is 1, it should refer to *Name1, if it's 2 it should refer to *Name2.
The method should return just the name with the asterisk (*Name2).
I have attempted to play around with substrings, taking the first delimited * and ending when we reach a character that isn't a letter, number, underscore or hyphen, but the logic just isn't setting in.
I know this is similar to a few problems on SO but I can't find anything this specific. Any help is appreciated.
This is what's left of my very vague attempt so far. Based on this thread:
public string GetIndexedNames(string message, int index)
{
int strStart = message.IndexOf("#") + "#".Length;
int strEnd = message.LastIndexOf(" ");
String result = message.Substring(strStart, strEnd - strStart);
}
If you want to do it the old school way, then something like:
public static void Main(string[] args)
{
string message = "Hello, I am *Name1, how are you doing *Name2?";
string name1 = GetIndexedNames(message, "*", 1);
string name2 = GetIndexedNames(message, "*", 2);
Console.WriteLine(message);
Console.WriteLine(name1);
Console.WriteLine(name2);
Console.ReadLine();
}
public static string GetIndexedNames(string message, string singleCharDelimiter, int index)
{
string valid = "abcdefghijlmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-";
string[] parts = message.Split(singleCharDelimiter.ToArray());
if (parts.Length >= index)
{
StringBuilder sb = new StringBuilder();
for(int i = 0; i < parts[index].Length; i++)
{
string character = parts[index].Substring(i, 1);
if (valid.Contains(character))
{
sb.Append(character);
}
else
{
return sb.ToString();
}
}
return sb.ToString();
}
return "";
}
You can try using regular expressions to match the names. Assuming that name is a sequence of word characters (letters or digits):
using System.Linq;
using System.Text.RegularExpressions;
...
// Either name with asterisk *Name or null
// index is 1-based
private static ObtainName(string source, int index) => Regex
.Matches(source, #"\*\w+")
.Cast<Match>()
.Select(match => match.Value)
.Distinct() // in case the same name repeats several times
.ElementAtOrDefault(index - 1);
Demo:
string name = ObtainName(
"Hello, I am *Name1, how are you doing *Name2?", 2);
Console.Write(name);
Outcome:
*Name2
Perhaps not the most elegant solution, but if you want to use IndexOf, use a loop:
public static string GetIndexedNames(string message, int index, char marker='*')
{
int lastFound = 0;
for (int i = 0; i < index; i++) {
lastFound = message.IndexOf(marker, lastFound+1);
if (lastFound == -1) return null;
}
var space = message.IndexOf(' ', lastFound);
return space == -1 ? message.Substring(lastFound) : message.Substring(lastFound, space - lastFound);
}
I have made a program that evaluates a string by splitting it at a pipeline, the string are randomly generated and sometimes whitespace is a part of what need to be evaluated.
HftiVfzRIDBeotsnU uabjvLPC | LstHCfuobtv eVzDUBPn jIRfai
This string is same length on either side(2 x whitespace on left side of pipeline), but my problem comes when i have to trim the space on both sides of the pipeline (i do this after splitting)
is there some way of making sure that i only trim 1 single space instead of them all.
my code so far:
foreach (string s in str)
{
int bugCount = 0;
string[] info = s.Split('|');
string testCase = info[0].TrimEnd();
char[] testArr = testCase.ToCharArray();
string debugInfo = info[1].TrimStart();
char[] debugArr = debugInfo.ToCharArray();
int arrBound = debugArr.Count();
for (int i = 0; i < arrBound; i++)
if (testArr[i] != debugArr[i])
bugCount++;
if (bugCount <= 2 && bugCount != 0)
Console.WriteLine("Low");
if (bugCount <= 4 && bugCount != 0)
Console.WriteLine("Medium");
if (bugCount <= 6 && bugCount != 0)
Console.WriteLine("High");
if (bugCount > 6)
Console.WriteLine("Critical");
else
Console.WriteLine("Done");
}
Console.ReadLine();
You have 2 options.
If there is always 1 space before and after the pipe, split on {space}|{space}.
myInput.Split(new[]{" | "},StringSplitOptions.None);
Otherwise, instead of using TrimStart() & TrimEnd() use SubString.
var split = myInput.Split('|');
var s1 = split[0].EndsWith(" ")
? split[0].SubString(0,split[0].Length-1)
: split[0];
var s2 = split[1].StartsWith(" ")
? split[1].SubString(1) // to end of line
: split[1];
Note, there is some complexity here - if the pipe has no space around it, but the last/first character is a legitimate (data) space character the above will cut it off. You need more logic, but hopefully this will get you started!
There is no way to tell the Trim.. methods family to stop after cutting out some number of characters.
In general case, you'd need to do it manually by inspecting the parts obtained after Split and checking their first/last characters and substring'ing to get the correct part.
However, in your case, there's a much simpler way - the Split can also take a string as an argument, and even more - a set of strings:
string[] info = s.Split(new []{ " | " });
// or even
string[] info = s.Split(new []{ " | ", " |", "| ", "|" });
That should take care of the single spaces around the pipe | character by simply treating them as a part of the separator.
This is a string extension to trim space for count times, just in case.
public static class StringExtension
{
/// <summary>
/// Trim space at the end of string for count times
/// </summary>
/// <param name="input"></param>
/// <param name="count">number of space at the end to trim</param>
/// <returns></returns>
public static string TrimEnd(this string input, int count = 1)
{
string result = input;
if (count <= 0)
{
return result;
}
if (result.EndsWith(new string(' ', count)))
{
result = result.Substring(0, result.Length - count);
}
return result;
}
/// <summary>
/// Trim space at the start of string for count times
/// </summary>
/// <param name="input"></param>
/// <param name="count">number of space at the start to trim</param>
/// <returns></returns>
public static string TrimStart(this string input, int count = 1)
{
string result = input;
if (count <= 0)
{
return result;
}
if (result.StartsWith(new string(' ', count)))
{
result = result.Substring(count);
}
return result;
}
}
In the main
static void Main(string[] args)
{
string a = "1234 ";
string a1 = a.TrimEnd(1); // returns "1234 "
string a2 = a.TrimEnd(2); // returns "1234"
string a3 = a.TrimEnd(3); // returns "1234 "
string b = " 5678";
string b1 = b.TrimStart(1); // returns " 5678"
string b2 = b.TrimStart(2); // returns "5678"
string b3 = b.TrimStart(3); // returns " 5678"
}
I need to take a sentence in that is all on one line with no spaces and each new word has a captial letter EX. "StopAndSmellTheRoses" and then convert it to "Stop and smell the roses" This is my function that I have but I keep getting an argument out of range error on the insert method. Thanks for any help in advance.
private void FixSentence()
{
// String to hold our sentence in trim at same time
string sentence = txtSentence.Text.Trim();
// loop through the string
for (int i = 0; i < sentence.Length; i++)
{
if (char.IsUpper(sentence, i) & sentence[i] != 0)
{
// Change to lowercase
char.ToLower(sentence[i]);
// Insert space behind the character
// This is where I get my error
sentence = sentence.Insert(i-1, " ");
}
}
// Show our Fixed Sentence
lblFixed.Text = "";
lblFixed.Text = "Fixed: " + sentence;
}
The best way to build up a String in this manner is to use a StringBuilder instance.
var sentence = txtSentence.Text.Trim();
var builder = new StringBuilder();
foreach (var cur in sentence) {
if (Char.IsUpper(cur) && builder.Length != 0) {
builder.Append(' ');
}
builder.Append(cur);
}
// Show our Fixed Sentence
lblFixed.Text = "";
lblFixed.Text = "Fixed: " + builder.ToString();
Using the Insert method creates a new string instance every time resulting in a lot of needlessly allocated values. The StringBuilder though won't actually allocate a String until you call the ToString method.
You can't modify the sentence variable in the loop that is going through it.
Instead, you need to have a second string variable that you append all of the found words.
Here is the answer
var finalstr = Regex.Replace(
"StopAndSmellTheRoses",
"(?<=[a-z])(?<x>[A-Z])|(?<=.)(?<x>[A-Z])(?=[a-z])|(?<=[^0-9])(?<x>[0-9])(?=.)",
me => " " + me.Value.ToLower()
);
will output
Stop and smell the roses
Another version:
public static class StringExtensions
{
public static string FixSentence(this string instance)
{
char[] capitals = Enumerable.Range(65, 26).Select(x => (char)x).ToArray();
string[] words = instance.Split(capitals);
string result = string.Join(' ', words);
return char.ToUpper(result[0]) + result.Substring(1).ToLower();
}
}
i want to retrive some number from string, for example "valueID = 234232" or "valueID = 2" or "valueID=23" or "valueID= 2" or "valueID =234", so what is the easiest way to get this number assuming that after this number is space " " or end of line?
string input = "valueID = 234232";
var split = input.Split(new char[] {'='});
int value = int.Parse(split[1].Trim());
As long as your sure there will be a number in there
int.parse( Regex.match(String, #"\d+").value)
How about using a regex:
Match match = Regex.Match(input, #"\d+");
if (match.Success)
{
number = int.Parse(match.Value);
}
Here's some flexible code I use all the time for this sort of thing:
public const string FilterDigits = "0123456789";
public const string FilterLetters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
/// <summary>
/// Strips away any characters not defined in validChars and returns the result.
/// </summary>
public static string FilterTo(string text, string validChars)
{
StringBuilder Result = new StringBuilder();
for (int i = 1; i <= text.Length; i++) {
char CurrentChar = Convert.ToChar(Strings.Mid(text, i, 1));
if (validChars.Contains(CurrentChar)) {
Result.Append(CurrentChar);
}
}
return Result.ToString;
}
Then you can just call:
int.parse(FilterTo("valueID=23", FilterDigits));
It could also be turned into a handy extension method, then you could do:
int.parse("valueID=23".FilterTo(FilterDigits));
Once you've parsed out your potential number (through regex, split, substr, etc), TryParse is a great improvement (since .NET 3.5 at least):
string myPotentialNumber = "1";
int myNumber;
bool isNumber = int.TryParse(myPotentialNumber, out myNumber);
if( isNumber )
{
//do something
}
else
{
//throw error
}
TryParse() is exception safe, which makes it a bit faster and cleaner for many types of conversions.
I would like to split a string with delimiters but keep the delimiters in the result.
How would I do this in C#?
If the split chars were ,, ., and ;, I'd try:
using System.Text.RegularExpressions;
...
string[] parts = Regex.Split(originalString, #"(?<=[.,;])")
(?<=PATTERN) is positive look-behind for PATTERN. It should match at any place where the preceding text fits PATTERN so there should be a match (and a split) after each occurrence of any of the characters.
If you want the delimiter to be its "own split", you can use Regex.Split e.g.:
string input = "plum-pear";
string pattern = "(-)";
string[] substrings = Regex.Split(input, pattern); // Split on hyphens
foreach (string match in substrings)
{
Console.WriteLine("'{0}'", match);
}
// The method writes the following to the console:
// 'plum'
// '-'
// 'pear'
So if you are looking for splitting a mathematical formula, you can use the following Regex
#"([*()\^\/]|(?<!E)[\+\-])"
This will ensure you can also use constants like 1E-02 and avoid having them split into 1E, - and 02
So:
Regex.Split("10E-02*x+sin(x)^2", #"([*()\^\/]|(?<!E)[\+\-])")
Yields:
10E-02
*
x
+
sin
(
x
)
^
2
Building off from BFree's answer, I had the same goal, but I wanted to split on an array of characters similar to the original Split method, and I also have multiple splits per string:
public static IEnumerable<string> SplitAndKeep(this string s, char[] delims)
{
int start = 0, index;
while ((index = s.IndexOfAny(delims, start)) != -1)
{
if(index-start > 0)
yield return s.Substring(start, index - start);
yield return s.Substring(index, 1);
start = index + 1;
}
if (start < s.Length)
{
yield return s.Substring(start);
}
}
Just in case anyone wants this answer aswell...
Instead of string[] parts = Regex.Split(originalString, #"(?<=[.,;])") you could use string[] parts = Regex.Split(originalString, #"(?=yourmatch)") where yourmatch is whatever your separator is.
Supposing the original string was
777- cat
777 - dog
777 - mouse
777 - rat
777 - wolf
Regex.Split(originalString, #"(?=777)") would return
777 - cat
777 - dog
and so on
This version does not use LINQ or Regex and so it's probably relatively efficient. I think it might be easier to use than the Regex because you don't have to worry about escaping special delimiters. It returns an IList<string> which is more efficient than always converting to an array. It's an extension method, which is convenient. You can pass in the delimiters as either an array or as multiple parameters.
/// <summary>
/// Splits the given string into a list of substrings, while outputting the splitting
/// delimiters (each in its own string) as well. It's just like String.Split() except
/// the delimiters are preserved. No empty strings are output.</summary>
/// <param name="s">String to parse. Can be null or empty.</param>
/// <param name="delimiters">The delimiting characters. Can be an empty array.</param>
/// <returns></returns>
public static IList<string> SplitAndKeepDelimiters(this string s, params char[] delimiters)
{
var parts = new List<string>();
if (!string.IsNullOrEmpty(s))
{
int iFirst = 0;
do
{
int iLast = s.IndexOfAny(delimiters, iFirst);
if (iLast >= 0)
{
if (iLast > iFirst)
parts.Add(s.Substring(iFirst, iLast - iFirst)); //part before the delimiter
parts.Add(new string(s[iLast], 1));//the delimiter
iFirst = iLast + 1;
continue;
}
//No delimiters were found, but at least one character remains. Add the rest and stop.
parts.Add(s.Substring(iFirst, s.Length - iFirst));
break;
} while (iFirst < s.Length);
}
return parts;
}
Some unit tests:
text = "[a link|http://www.google.com]";
result = text.SplitAndKeepDelimiters('[', '|', ']');
Assert.IsTrue(result.Count == 5);
Assert.AreEqual(result[0], "[");
Assert.AreEqual(result[1], "a link");
Assert.AreEqual(result[2], "|");
Assert.AreEqual(result[3], "http://www.google.com");
Assert.AreEqual(result[4], "]");
A lot of answers to this! One I knocked up to split by various strings (the original answer caters for just characters i.e. length of 1). This hasn't been fully tested.
public static IEnumerable<string> SplitAndKeep(string s, params string[] delims)
{
var rows = new List<string>() { s };
foreach (string delim in delims)//delimiter counter
{
for (int i = 0; i < rows.Count; i++)//row counter
{
int index = rows[i].IndexOf(delim);
if (index > -1
&& rows[i].Length > index + 1)
{
string leftPart = rows[i].Substring(0, index + delim.Length);
string rightPart = rows[i].Substring(index + delim.Length);
rows[i] = leftPart;
rows.Insert(i + 1, rightPart);
}
}
}
return rows;
}
This seems to work, but its not been tested much.
public static string[] SplitAndKeepSeparators(string value, char[] separators, StringSplitOptions splitOptions)
{
List<string> splitValues = new List<string>();
int itemStart = 0;
for (int pos = 0; pos < value.Length; pos++)
{
for (int sepIndex = 0; sepIndex < separators.Length; sepIndex++)
{
if (separators[sepIndex] == value[pos])
{
// add the section of string before the separator
// (unless its empty and we are discarding empty sections)
if (itemStart != pos || splitOptions == StringSplitOptions.None)
{
splitValues.Add(value.Substring(itemStart, pos - itemStart));
}
itemStart = pos + 1;
// add the separator
splitValues.Add(separators[sepIndex].ToString());
break;
}
}
}
// add anything after the final separator
// (unless its empty and we are discarding empty sections)
if (itemStart != value.Length || splitOptions == StringSplitOptions.None)
{
splitValues.Add(value.Substring(itemStart, value.Length - itemStart));
}
return splitValues.ToArray();
}
Recently I wrote an extension method do to this:
public static class StringExtensions
{
public static IEnumerable<string> SplitAndKeep(this string s, string seperator)
{
string[] obj = s.Split(new string[] { seperator }, StringSplitOptions.None);
for (int i = 0; i < obj.Length; i++)
{
string result = i == obj.Length - 1 ? obj[i] : obj[i] + seperator;
yield return result;
}
}
}
I'd say the easiest way to accomplish this (except for the argument Hans Kesting brought up) is to split the string the regular way, then iterate over the array and add the delimiter to every element but the last.
To avoid adding character to new line try this :
string[] substrings = Regex.Split(input,#"(?<=[-])");
result = originalString.Split(separator);
for(int i = 0; i < result.Length - 1; i++)
result[i] += separator;
(EDIT - this is a bad answer - I misread his question and didn't see that he was splitting by multiple characters.)
(EDIT - a correct LINQ version is awkward, since the separator shouldn't get concatenated onto the final string in the split array.)
Iterate through the string character by character (which is what regex does anyway.
When you find a splitter, then spin off a substring.
pseudo code
int hold, counter;
List<String> afterSplit;
string toSplit
for(hold = 0, counter = 0; counter < toSplit.Length; counter++)
{
if(toSplit[counter] = /*split charaters*/)
{
afterSplit.Add(toSplit.Substring(hold, counter));
hold = counter;
}
}
That's sort of C# but not really. Obviously, choose the appropriate function names.
Also, I think there might be an off-by-1 error in there.
But that will do what you're asking.
veggerby's answer modified to
have no string items in the list
have fixed string as delimiter like "ab" instead of single character
var delimiter = "ab";
var text = "ab33ab9ab"
var parts = Regex.Split(text, $#"({Regex.Escape(delimiter)})")
.Where(p => p != string.Empty)
.ToList();
// parts = "ab", "33", "ab", "9", "ab"
The Regex.Escape() is there just in case your delimiter contains characters which regex interprets as special pattern commands (like *, () and thus have to be escaped.
using System.Collections.Generic;
using System.Text.RegularExpressions;
namespace ConsoleApplication9
{
class Program
{
static void Main(string[] args)
{
string input = #"This;is:a.test";
char sep0 = ';', sep1 = ':', sep2 = '.';
string pattern = string.Format("[{0}{1}{2}]|[^{0}{1}{2}]+", sep0, sep1, sep2);
Regex regex = new Regex(pattern);
MatchCollection matches = regex.Matches(input);
List<string> parts=new List<string>();
foreach (Match match in matches)
{
parts.Add(match.ToString());
}
}
}
}
I wanted to do a multiline string like this but needed to keep the line breaks so I did this
string x =
#"line 1 {0}
line 2 {1}
";
foreach(var line in string.Format(x, "one", "two")
.Split("\n")
.Select(x => x.Contains('\r') ? x + '\n' : x)
.AsEnumerable()
) {
Console.Write(line);
}
yields
line 1 one
line 2 two
I came across same problem but with multiple delimiters. Here's my solution:
public static string[] SplitLeft(this string #this, char[] delimiters, int count)
{
var splits = new List<string>();
int next = -1;
while (splits.Count + 1 < count && (next = #this.IndexOfAny(delimiters, next + 1)) >= 0)
{
splits.Add(#this.Substring(0, next));
#this = new string(#this.Skip(next).ToArray());
}
splits.Add(#this);
return splits.ToArray();
}
Sample with separating CamelCase variable names:
var variableSplit = variableName.SplitLeft(
Enumerable.Range('A', 26).Select(i => (char)i).ToArray());
I wrote this code to split and keep delimiters:
private static string[] SplitKeepDelimiters(string toSplit, char[] delimiters, StringSplitOptions splitOptions = StringSplitOptions.None)
{
var tokens = new List<string>();
int idx = 0;
for (int i = 0; i < toSplit.Length; ++i)
{
if (delimiters.Contains(toSplit[i]))
{
tokens.Add(toSplit.Substring(idx, i - idx)); // token found
tokens.Add(toSplit[i].ToString()); // delimiter
idx = i + 1; // start idx for the next token
}
}
// last token
tokens.Add(toSplit.Substring(idx));
if (splitOptions == StringSplitOptions.RemoveEmptyEntries)
{
tokens = tokens.Where(token => token.Length > 0).ToList();
}
return tokens.ToArray();
}
Usage example:
string toSplit = "AAA,BBB,CCC;DD;,EE,";
char[] delimiters = new char[] {',', ';'};
string[] tokens = SplitKeepDelimiters(toSplit, delimiters, StringSplitOptions.RemoveEmptyEntries);
foreach (var token in tokens)
{
Console.WriteLine(token);
}