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I have string in my c# code
a,b,c,d,"e,f",g,h
I want to replace "e,f" with "e f" i.e. ',' which is inside inverted comma should be replaced by space.
I tried using string.split but it is not working for me.
OK, I can't be bothered to think of a regex approach so I am going to offer an old fashioned loop approach which will work:
string DoReplace(string input)
{
bool isInner = false;//flag to detect if we are in the inner string or not
string result = "";//result to return
foreach(char c in input)//loop each character in the input string
{
if(isInner && c == ',')//if we are in an inner string and it is a comma, append space
result += " ";
else//otherwise append the character
result += c;
if(c == '"')//if we have hit an inner quote, toggle the flag
isInner = !isInner;
}
return result;
}
NOTE: This solution assumes that there can only be one level of inner quotes, for example you cannot have "a,b,c,"d,e,"f,g",h",i,j" - because that's just plain madness!
For the scenario where you only need to match one pair of letters, the following regex will work:
string source = "a,b,c,d,\"e,f\",g,h";
string pattern = "\"([\\w]),([\\w])\"";
string replace = "\"$1 $2\"";
string result = Regex.Replace(source, pattern, replace);
Console.WriteLine(result); // a,b,c,d,"e f",g,h
Breaking apart the pattern, it is matching any instance where there is a "X,X" sequence where X is any letter, and is replacing it with the very same sequence, with a space in between the letters instead of a comma.
You could easily extend this if you needed to to have it match more than one letter, etc, as needed.
For the case where you can have multiple letters separated by commas within quotes that need to be replaced, the following can do it for you. Sample text is a,b,c,d,"e,f,a",g,h:
string source = "a,b,c,d,\"e,f,a\",g,h";
string pattern = "\"([ ,\\w]+),([ ,\\w]+)\"";
string replace = "\"$1 $2\"";
string result = source;
while (Regex.IsMatch(result, pattern)) {
result = Regex.Replace(result, pattern, replace);
}
Console.WriteLine(result); // a,b,c,d,"e f a",g,h
This does something similar compared to the first one, but just removes any comma that is sandwiched by letters surrounded by quotes, and repeats it until all cases are removed.
Here's a somewhat fragile but simple solution:
string.Join("\"", line.Split('"').Select((s, i) => i % 2 == 0 ? s : s.Replace(",", " ")))
It's fragile because it doesn't handle flavors of CSV that escape double-quotes inside double-quotes.
Use the following code:
string str = "a,b,c,d,\"e,f\",g,h";
string[] str2 = str.Split('\"');
var str3 = str2.Select(p => ((p.StartsWith(",") || p.EndsWith(",")) ? p : p.Replace(',', ' '))).ToList();
str = string.Join("", str3);
Use Split() and Join():
string input = "a,b,c,d,\"e,f\",g,h";
string[] pieces = input.Split('"');
for ( int i = 1; i < pieces.Length; i += 2 )
{
pieces[i] = string.Join(" ", pieces[i].Split(','));
}
string output = string.Join("\"", pieces);
Console.WriteLine(output);
// output: a,b,c,d,"e f",g,h
Using regular expressions I'm trying to match a string, which has a substring consisting of unknown number of repeats (one or more) and then replace the repeating substring with the same number of replacement strings.
If the Regexp is "(st)[a]+(ck)", then I want to get these kind of results:
"stack" => "stOck"
"staaack" => "stOOOck" //so three times "a" to be replaced with three times "O"
"staaaaack" => "stOOOOOck"
How do I do that?
Either C# or AS3 would do.
If you use .net you can do this
find: (?<=\bsta*)a(?=a*ck\b)
replace: o
If you want to change all sta+ck that are substring of other words, only remove the \b
Since I am not familiar with either C# or AS3, I will write a solution in JavaScript, but the concept in the solution can be used for C# code or AS3 code.
var str = "stack stackoverflow staaaaaack stOackoverflow should not replace";
var replaced = str.replace(/st(a+)ck/g, function ($0, $1) {
var r = "";
for (var i = 0; i < $1.length; i++) {
r += "O";
}
return "st" + r + "ck";
});
Output:
"stOck stOckoverflow stOOOOOOck stOackoverflow should not replace"
In C#, you would use Regex.Replace(String, String, MatchEvaluator) (or other Regex.Replace methods that takes in a MatchEvaluator delegate) to achieve the same effect.
In AS3, you can pass a function as replacement, similar to how I did above in JavaScript. Check out the documentation of String.replace() method.
For AS3 you can pass a function to the replace method on the String object where matching elements are into the arguments array. So you can build and return a new String with all the 'a' replaced by 'O'
for example:
// first way explicit loop
var s:String="staaaack";
trace("before", s);
var newStr:String = s.replace(/(st)(a+)(ck)/g, function():String{
var ret:String=arguments[1]; // here match 'st'
//arguments[2] match 'aaa..'
for (var i:int=0, len:int=arguments[2].length; i < len; i++)
ret += "O";
return ret + arguments[3]; // arguments[3] match 'ck'
});
trace("after", newStr); // output stOOOOck
// second way array and join
var s1:String="staaaack staaaaaaaaaaaaack stack paaaack"
trace("before", s1)
var after:String = s1.replace(/(st)(a+)(ck)/g, function():String{
return arguments[1]+(new Array(arguments[2].length+1)).join("O")+arguments[3]
})
trace("after", after)
here live example on wonderfl : http://wonderfl.net/c/bOwE
Why not use the String Replace() method instead?
var str = "stack";
str = str.Replace("a", "O");
I would do it like this:
String s = "Staaack";
Console.WriteLine(s);
while (Regex.Match(s,"St[O]*([a]{1})[a]*ck").Success){
s = Regex.Replace(s,"(St[O]*)([a]{1})([a]*ck)", "$1O$3");
Console.WriteLine(s);
}
Console.WriteLine(s);
Console.ReadLine();
it replaces one a with every iteration, until no more as can be found.
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Remove characters after specific character in string, then remove substring?
I have a string variabel that contains a text like this:
"Hello My name is B and I love soccer. I live in California."
I want to cut the text after the first '.' so the text displays
"Hello My name is B and I love soccer."
How can I do it in the simpliest way?
I tried:
Char Mychar = '.';
Stringvariabel.trimstart(Mychar);
But I guess it's wrong.
Char Mychar = '.';
Stringvariabel = Stringvariabel.Split(Mychar).First() + Mychar.toString();
If you're only interested in the first sentence, then just grab a substring starting at the beginning and ending at the '.'.
Stringvariabel.Substring(0, Stringvariabel.IndexOf('.') + 1);
You can use string.Split to get the result:
string input = "Hello My name is B and I love soccer. I live in California. ";
string result = string.Format("{0}.", input.Split('.').First());
Make use of IndexOf function will do work for you..
string input = "Hello My name is B and I love soccer. I live in California. ";
int i = input .IndexOf('.');
string result = s.Substring(0,i+1);
One convenient way is to use string.Split and ask for just the first part:
var firstPart = input.Split(new[] { '.' }, 1).First();
This is quite efficient because it won't continue processing the string after the first dot, but it will remove the dot (if it exists) and you will not be able to tell if there was a dot in the first place.
The other option is string.IndexOf and a conditional:
var index = input.IndexOf(".");
if (index != -1) {
input = input.SubString(0, index);
}
TrimStart removes characters from the start of a string that are in the list you give it. It would only remove a . if it appears at the very start.
You can find the first . and take a substring up to that point:
stringVar.Substring(0, stringVar.IndexOf('.') + 1);
You can do something like below
stringVariable.Split('.')[0]
or
stringVariable.SubString(0, stringVariable.IndexOf(".") + 1)
Hope this Helps!!
The simplest way would be to take the substring up until the first occurrence of the character.
public string TrimAtFirstChar(string s, char c)
{
int index = s.IndexOf(c);
if(index == -1) //there is no '.' in the string
return s;
return s.Substring(0, index)
}
Alternately, to avoid worrying about the case where there is no '.', you could use stringvariable.Split('.')[0].
Take a look at the String.Split method.
var myString = "Hello My name is B and I love soccer. I live in California. ";
var firstPart = myString.Split('.')[0];
var splitLine = yourString.Split('.');
if (splitLine != null && splitLine.Count > 0)
return splitLine[0];
Without split, only using Substring and IndexOf (which is more efficient when the text is very large):
int index = text.IndexOf(".") + 1;
String result = text;
if(index > 0)
result = text.Substring(0, index);
http://ideone.com/HL6GwN
Please be aware that String.Split() can have an impact, cause you create an array that contains all substrings delimited by the given separator, but you are only interested in the first occurence. So using IndexOf() and Substring() makes much more sense.
string input = "Hello My name is B and I love soccer. I live in California. ";
var index = input.IndexOf(".");
var result = index > 0
? input.Substring(0, index)
: input;
variablename.Substring(0, variablename.IndexOf('.') + 1);
Is it possible to pass over a string, finding the white spaces?
For example a data set of:
string myString = "aa bbb cccc dd";
How could I loop through and detect each white space, and manipulate that space?
I need to do this in the most effecient way possible.
Thanks.
UPDATE:
I need to manipulate the space by increasing the white space from an integer value. So for instance increase the space to have 3 white spaces instead of one. I'd like to make it go through each white space in one loop, any method of doing this already in .NET? By white space I mean a ' '.
You can use the Regex.Replace method. This will replace any group of white space character with a dash:
myString = Regex.Replace(myString, "(\s+)", m => "-");
Update:
This will find groups of space characters and replace with the tripple amount of spaces:
myString = Regex.Replace(
myString,
"( +)",
m => new String(' ', m.Groups[1].Value.Length * 3)
);
However, that's a bit too simple to make use of regular expressions. You can do the same with a regular replace:
myString = myString.Replace(" ", " ");
This will replace each space intead of replace groups of spaces, but the regular replace is much simpler than Regex.Replace, so it should still be at least as fast, and the code is simpler.
If you want to replace all whitespace in one swoop, you can do:
// changes all strings to dashes
myString.Replace(' ', '-');
If you want to go case by case (that is, not just a mass replace), you can loop through IndexOf():
int pos = myString.IndexOf(' ');
while (pos >= 0)
{
// do whatever you want with myString # pos
// find next
pos = myString.IndexOf(' ', pos + 1);
}
UPDATE
As per your update, you could replace single spaces with the number of spaces specified by a variable (such as numSpaces) as follows:
myString.Replace(" ", new String(' ', numSpaces));
If you just want to replace all spaces with some other character:
myString = myString.Replace(' ', 'x');
If you need the possibility of doing something different to each:
foreach(char c in myString)
{
if (c == ' ')
{
// do something
}
}
Edit:
Per your comment clarifying your question:
To change each space to three spaces, you can do this:
myString = myString.Replace(" ", " ");
However note that this doesn't take into account instances where your input string already has two or more spaces. If that is a possibility you will want to use a regex.
Depending on what you're tring to do:
for(int k = 0; k < myString.Length; k++)
{
if(myString[k].IsWhiteSpace())
{
// do something with it
}
}
The above is a single pass through the string, so it's O(n). You can't really get more efficient that that.
However, if you want to manipulate the original string your best bet is to Use a StringBuilder to process the changes:
StringBuilder sb = new StringBuilder(myString);
for(int k = 0; k < myString.Length; k++)
{
if(myString[k].IsWhiteSpace())
{
// do something with sb
}
}
Finally, don't forget about Regular Expressions. It may not always be the most efficient method in terms of code run-time complexity but as far as efficiency of coding it may be a good trade-off.
For instance, here's a way to match all white spaces:
var rex = new System.Text.RegularExpressions.Regex("[^\\s](\\s+)[^\\s]");
var m = rex.Match(myString);
while(m.Success)
{
// process the match here..
m.NextMatch();
}
And here's a way to replace all white spaces with an arbitrary string:
var rex = new System.Text.RegularExpressions.Regex("\\s+");
String replacement = "[white_space]";
// replaces all occurrences of white space with the string [white_space]
String result = rex.Replace(myString, replacement);
Use string.Replace().
string newString = myString.Replace(" ", " ");
LINQ query below returns a set of anonymous type items with two properties - "sybmol" represents a white space character, and "index" - index in the input sequence. After that you have all whitespace characters and a position in the input sequence, now you can do what you want with this.
string myString = "aa bbb cccc dd";
var res = myString.Select((c, i) => new { symbol = c, index = i })
.Where(c => Char.IsWhiteSpace(c.symbol));
EDIT: For educational purposes below is implementation you are looking for, but obviously in real system use built in string constructor and String.Replace() as shown in other answers
string myString = "aa bbb cccc dd";
var result = this.GetCharacters(myString, 5);
string output = new string(result.ToArray());
public IEnumerable<char> GetCharacters(string input, int coeff)
{
foreach (char c in input)
{
if (Char.IsWhiteSpace(c))
{
int counter = coeff;
while (counter-- > 0)
{
yield return c;
}
}
else
{
yield return c;
}
}
}
var result = new StringBuilder();
foreach(Char c in myString)
{
if (Char.IsWhiteSpace(c))
{
// you can do what you wish here. strings are immutable, so you can only make a copy with the results you want... hence the "result" var.
result.Append('_'); // for example, replace space with _
}
else result.Append(c);
}
myString = result.ToString();
If you want to replace the white space with, e.g. '_', you can using String.Replace.
Example:
string myString = "aa bbb cccc dd";
string newString = myString.Replace(" ", "_"); // gives aa_bbb_cccc_dd
In case you want to left/right justify your string
int N=10;
string newstring = String.Join(
"",
myString.Split(' ').Select(s=>s.PadRight(N-s.Length)));
I need to extract and remove a word from a string. The word should be upper-case, and following one of the delimiters /, ;, (, - or a space.
Some Examples:
"this is test A/ABC"
Expected output: "this is test A" and "ABC"
"this is a test; ABC/XYZ"
Expected output: "this is a test; ABC" and "XYZ"
"This TASK is assigned to ANIL/SHAM in our project"
Expected output: "This TASK is assigned to ANIL in our project" and "SHAM"
"This TASK is assigned to ANIL/SHAM in OUR project"
Expected output: "This TASK is assigned to ANIL/SHAM in project" and "OUR"
"this is test AWN.A"
Expected output: "this is test" and "AWN.A"
"XETRA-DAX"
Expected output: "XETRA" and "DAX"
"FTSE-100"
Expected output: "-100" and "FTSE"
"ATHEX"
Expected output: "" and "ATHEX"
"Euro-Stoxx-50"
Expected output: "Euro-Stoxx-50" and ""
How can I achieve that?
An "intelligent" version:
string strValue = "this is test A/ABC";
int ix = strValue.LastIndexOfAny(new[] { '/', ' ', ';', '(', '-' });
var str1 = strValue.Substring(0, ix);
var str2 = strValue.Substring(ix + 1);
A "stupid LINQ" version:
var str3 = new string(strValue.Reverse().SkipWhile(p => p != '/' && p != ' ' && p != ';' && p != '(' && p != '-').Skip(1).Reverse().ToArray());
var str4 = new string(strValue.Reverse().TakeWhile(p => p != '/' && p != ' ' && p != ';' && p != '(' && p != '-').Reverse().ToArray());
both cases are WITHOUT checks. The OP can add checks if he wants them.
For the second question, using LINQ is REALLY too much difficult. With a Regex it's "easily doable".
var regex = new Regex("^(.*[A-Z]+)([-/ ;(]+)([A-Z]+)(.*?)$");
var strValueWithout = regex.Replace(strValue, "$1$4");
var extractedPart = regex.Replace(strValue, "$3");
For the third question
var regex = new Regex("^(.*?)([A-Z.]*)([-/ ;(]+)([A-Z.]+)(.*?)$", RegexOptions.RightToLeft);
var strValueWithout = regex.Replace(strValue, "$1$2$5");
var extractedPart = regex.Replace(strValue, "$4");
With code sample: http://ideone.com/5OSs0
Another update (it's becoming BORING)
Regex Regex = new Regex(#"^(?<1>.*?)(?<2>[-/ ;(]*)(?<=\b)(?<3>[A-Z.]+)(?=\b)(?<4>.*?)$|^(?<1>.*)$", RegexOptions.RightToLeft);
Regex Regex2 = new Regex(#"^(?<1>.*?)(?<2>[-/ ;(]*)(?<=\b)(?<3>(?:\p{Lu}|\.)+)(?=\b)(?<4>.*?)$|^(?<1>.*)$", RegexOptions.RightToLeft);
var str1 = Regex.Replace(str, "$1$4");
var str2 = Regex.Replace(str, "$3");
The difference between the two is that the first will use A-Z as upper case characters, the second one will use other "upper case" characters, for example ÀÈÉÌÒÙ
With code sample: http://ideone.com/FqcmY
This should work according to the new requirements: it should find the last separator that is wrapped with uppercase words:
Match lastSeparator = Regex.Match(strExample,
#"(?<=\b\p{Lu}+)[-/ ;(](\p{Lu}+)\b",
RegexOptions.RightToLeft); // last match
string main = lastSeparator.Result("$`$'"); // before and after the match
string word = lastSeparator.Groups[1].Value; // word after the separator
This regex is a little tricky. Main tricks:
Use RegexOptions.RightToLeft to find the last match.
Use of Match.Result for a replace.
$`$' as replacement string: http://www.regular-expressions.info/refreplace.html
\p{Lu} for upper-case letters, you can change that to [A-Z] if your more comfortable with that.
If the word shouldn't follow an upper case word, you can simplify the regex to:
#"[-/ ;(](\p{Lu}+)\b"
If you want other characters as well, you can use a character class (and maybe remove \b). For example:
#"[-/ ;(]([\p{Lu}.,]+)"
Working example: http://ideone.com/U9AdK
use a List of strings, set all the words to it
find the index of the / then use ElementAt() to determine the word to split which is "SHAM" in your question.
in the below sentence of yours your index of / will be 6.
string strSentence ="This TASK is assigned to ANIL/SHAM in our project";
then use ElementAt(6) at the end of
index is the index of the / in your List<string>
str = str.Select(s => strSentence.ElementAt(index+1)).ToList();
this will return you the SHAM
str = str.Delete(s => strSentence.ElementAt(index+1));
this will delete the SHAM then just print the strSentence without SHAM
if you dont want to use a list of strings you can use the " " to determinate the words in your sentence i think, but that would be a long way to go.
the idea of mine is right i think but the code may not be that flawless.
You can use a combination of the string.Split() method and the Regex class. A simple Split is suitable for simple cases, such as splitting according to the character /. Regular expressions are perfect for matching more complicated patterns.
As a proof of concept, you could re-implement Split in LINQ using TakeWhile and SkipWhile
string strValue = "this is test A/ABC";
var s1=new string(
strValue
.TakeWhile(c => c!= '/')
.ToArray());
var s2=new string(
strValue
.SkipWhile(c => c!= '/')
.Skip(1)
.ToArray());
I think the resulting code is so mind-blowingly ugly that I hope you'll decide not to use linq