I have multiple words I want to replace with values, whats the best way to do this?
Example:
This is what I have done but it feels and looks so wrong
string s ="Dear <Name>, your booking is confirmed for the <EventDate>";
string s1 = s.Replace("<Name>", client.FullName);
string s2 =s1.Replace("<EventDate>", event.EventDate.ToString());
txtMessage.Text = s2;
There has to be a better way?
thanks
You could use String.Format.
string.Format("Dear {0}, your booking is confirmed for the {1}",
client.FullName, event.EventDate.ToString());
If you're planning on having a dynamic number of replacements, which could change at any time, and you want to make it a bit cleaner, you could always do something like this:
// Define name/value pairs to be replaced.
var replacements = new Dictionary<string,string>();
replacements.Add("<Name>", client.FullName);
replacements.Add("<EventDate>", event.EventDate.ToString());
// Replace
string s = "Dear <Name>, your booking is confirmed for the <EventDate>";
foreach (var replacement in replacements)
{
s = s.Replace(replacement.Key, replacement.Value);
}
To build on George's answer, you could parse the message into tokens then build the message from the tokens.
If the template string was much larger and there are more tokens, this would be a tad more efficient as you are not rebuilding the entire message for each token replacement. Also, the generation of the tokens could be moved out into a Singleton so it is only done once.
// Define name/value pairs to be replaced.
var replacements = new Dictionary<string, string>();
replacements.Add("<Name>", client.FullName);
replacements.Add("<EventDate>", event.EventDate.ToString());
string s = "Dear <Name>, your booking is confirmed for the <EventDate>";
// Parse the message into an array of tokens
Regex regex = new Regex("(<[^>]+>)");
string[] tokens = regex.Split(s);
// Re-build the new message from the tokens
var sb = new StringBuilder();
foreach (string token in tokens)
sb.Append(replacements.ContainsKey(token) ? replacements[token] : token);
s = sb.ToString();
You can chain the Replace operations together:
s = s.Replace(...).Replace(...);
Note that you don't need to create other strings to do this.
Using String.Format is the appropriate way, but only if you can change the original string to suit the brace formatting.
When you do multiple replaces it's much more efficient to use StringBuilder instead of string. Otherwise replace function is making a copy of the string every time you run it, wasting time and memory.
Try this code:
string MyString ="This is the First Post to Stack overflow";
MyString = MyString.Replace("the", "My").Replace("to", "to the");
Result: MyString ="This is My First Post to the Stack overflow";
Use String.Format:
const string message = "Dear {0}, Please call {1} to get your {2} from {3}";
string name = "Bob";
string callName = "Alice";
string thingy = "Book";
string thingyKeeper = "Library";
string customMessage = string.Format(message, name, callName, thingy, thingyKeeper);
Improving on what #Evan said...
string s ="Dear <Name>, your booking is confirmed for the <EventDate>";
string s1 = client.FullName;
string s2 = event.EventDate.ToString();
txtMessage.Text = s.Replace("<Name>", s1).Replace("EventDate", s2);
Related
This question already has answers here:
Replace Multiple String Elements in C#
(10 answers)
Closed 5 years ago.
My code uses String.Replace several times in a row:
mystring = mystring.Replace("somestring", variable1);
mystring = mystring.Replace("somestring2", variable2);
mystring = mystring.Replace("somestring3", variable1);
I suspect there's a better and faster way to do it. What would you suggest?
For an 'easy' alternative just use a StringBuilder....
StringBuilder sb = new StringBuilder("11223344");
string myString =
sb
.Replace("1", string.Empty)
.Replace("2", string.Empty)
.Replace("3", string.Empty)
.ToString();
Are we going for ways to make this harder to understand what is going on?
If so regex is your friend
var replacements = new Dictionary<string,string>()
{
{"somestring",someVariable1},
{"anotherstring",someVariable2}
};
var regex = new Regex(String.Join("|",replacements.Keys.Select(k => Regex.Escape(k))));
var replaced = regex.Replace(input,m => replacements[m.Value]);
Live: http://rextester.com/SXXB8348
You could at least chain the statements:
mystring = mystring.Replace("somestring", variable1)
.Replace("somestring2", variable2)
.Replace("somestring3", variable3);
Calling Replace three times is not only a valid answer, it might be the preferred one:
RegEx takes three steps: Parse, Execute, Formulate. But String.Replace is hard-coded, so in many cases it has superior speed. And a complex RegEx isn't as readable as a well-formatted chain of Replace statements. (Compare Jonathan's solution to Daniel's)
If you're still not convinced that Replace is better for your case, make a competition out of it! Try both methods side-by-side and use a Stopwatch to see how many milliseconds you save when using your data.
But DON'T optimize prematurely! Any developer will prefer readability and maintainability over a cryptic pile of spaghetti that performs three milliseconds faster.
This article Regex: replace multiple strings in a single pass with C# can be helpful:
static string MultipleReplace(string text, Dictionary replacements) {
return Regex.Replace(text,
"(" + String.Join("|", adict.Keys.ToArray()) + ")",
delegate(Match m) { return replacements[m.Value]; }
);
}
// somewhere else in code
string temp = "Jonathan Smith is a developer";
adict.Add("Jonathan", "David");
adict.Add("Smith", "Seruyange");
string rep = MultipleReplace(temp, adict);
Depending how your data is organized (what you're replacing) or how many you have; an array and loops might be a good approach.
string[] replaceThese = {"1", "2", "3"};
string data = "replace1allthe2numbers3";
foreach (string curr in replaceThese)
{
data = data.Replace(curr, string.Empty);
}
If you don't want to use RegEx add this class to your project,
It uses an extension method 'MultipleReplace':
public static class StringExtender
{
public static string MultipleReplace(this string text, Dictionary<string, string> replacements)
{
string retVal = text;
foreach (string textToReplace in replacements.Keys)
{
retVal = retVal.Replace(textToReplace, replacements[textToReplace]);
}
return retVal;
}
}
Then you can use this piece of code:
string mystring = "foobar";
Dictionary<string, string> stringsToReplace = new Dictionary<string,string>();
stringsToReplace.Add("somestring", variable1);
stringsToReplace.Add("somestring2", variable2);
stringsToReplace.Add("somestring3", variable1);
mystring = mystring.MultipleReplace(stringsToReplace);
My preferred method is to use the power of Regex to solve a multiple replace problem. The only issue with this approach is you only get to choose one string to replace with.
The following will replace all '/' or ':' with a '-' to make a valid file name.
Regex.Replace("invalid:file/name.txt", #"[/:]", "-");
I have a very large number of records in VCF file, the issue is When Phone Exports, It adds File with Tag name ."PHOTO", when I am importing this VCF file into other phone, It appends that information into name fields, causing too long and large Contact Name,
One thing I was doing was with manual find and delete, but in a file having 25000+ lines its so difficult,
I am thinking to move with REGX and remove, But there also issues, for some records, PHOTO Tag is the Last Record then END:VCARD at some points ITS, TEL;..
Here is the sample I have taken, Just one Clue, then Rest I will try at my own.
public string RemoveBlockComments(string InputString)
{
string strRegex = #"<regx>";
RegexOptions myRegexOptions = RegexOptions.Multiline;
Regex myRegex = new Regex(strRegex, myRegexOptions);
return myRegex.Replace(strTargetString, "");
}
Here is Test data:
PHOTO;TYPE=PNG;ENCODING=B:/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAMCAgMCAgMDAwMoHBwYIDAoMDAsK
CwsNDhIQDQ4KL/8QAtREAAgECBAQDBAcFBAQAAQJ3AAECAxEEBSEx
BhJB
TEL;TYPE=CELL:123456789
I want to remove All from PHOTO to BhJb(before Tel)
Possible Formats.
PHOTO....
Tel;
PHOTO....
EMAIL;
PHOTO....
END:VCARD
As per our chat discussion, it seems that you need to do 2 things:
Get the text after the TEL, EMAIL, END (or anything else you may have on the list of valid values there)
Get the part before that starts with PHOTO.
You can get the 2 values easily with your updated method:
private static String ReFormat(String str, out String removed)
{
Regex rgx = new Regex(#"(?msi)(?<removed>PHOTO\b.*?)(?=\b(?:TEL|EMAIL|END)\b)");
removed = rgx.Match(str).Groups["removed"].Value;
return str.Replace(removed, string.Empty);
}
And in the caller:
string removed = string.Empty;
string rest = ReFormat("PHOTO;TYPE=PNG;ENCODING=B:/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAMCAgMCAgMDAwMoHBwYIDAoMDAsK\r\nCwsNDhIQDQ4KL/8QAtREAAgECBAQDBAcFBAQAAQJ3AAECAxEEBSEx\r\nBhJB\r\nTEL;TYPE=CELL:123456789", out removed);
Or I think you can use a method that returns a list of key-value pairs:
private static List<KeyValuePair<String, String>> ReFormat(String str)
{
return Regex.Matches(str, #"(?msi)(?<photo>PHOTO\b.*?)(?<tel>\b(?:TEL|EMAIL|END)\b.*?(?=\bPHOTO|$))").Cast<Match>().Select(p=> new KeyValuePair<String, String>(p.Groups["photo"].Value, p.Groups["tel"].Value)).ToList();
}
And then
var my_result = ReFormat("PHOTO;TYPE=PNG;ENCODING=B:/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAMCAgMCAgMDAwMoHBwYIDAoMDAsK\r\nCwsNDhIQDQ4KL/8QAtREAAgECBAQDBAcFBAQAAQJ3AAECAxEEBSEx\r\nBhJB\r\nTEL;TYPE=CELL:123456789");
var mres1 = ReFormat("PHOTO;..jkh ohfhlahflkhasf fhasof\r\nTel:886886\r\ndataPHOTO:.ljlljhkdsghdsgd\n\rEmail:abc#abc.com..");
I've been using C# String.Format for formatting numbers before like this (in this example I simply want to insert a space):
String.Format("{0:### ###}", 123456);
output:
"123 456"
In this particular case, the number is a string. My first thought was to simply parse it to a number, but it makes no sense in the context, and there must be a prettier way.
Following does not work, as ## looks for numbers
String.Format("{0:### ###}", "123456");
output:
"123456"
What is the string equivalent to # when formatting? The awesomeness of String.Format is still fairly new to me.
You have to parse the string to a number first.
int number = int.Parse("123456");
String.Format("{0:### ###}", number);
of course you could also use string methods but that's not as reliable and less safe:
string strNumber = "123456";
String.Format("{0} {1}", strNumber.Remove(3), strNumber.Substring(3));
As Heinzi pointed out, you can not have format specifier for string arguments.
So, instead of String.Format, you may use following:
string myNum="123456";
myNum=myNum.Insert(3," ");
Not very beautiful, and the extra work might outweigh the gains, but if the input is a string on that format, you could do:
var str = "123456";
var result = String.Format("{0} {1}", str.Substring(0,3), str.Substring(3));
string is not a IFormattable
Console.WriteLine("123456" is IFormattable); // False
Console.WriteLine(21321 is IFormattable); // True
No point to supply a format if the argument is not IFormattable only way is to convert your string to int or long
We're doing string manipulation, so we could always use a regex.
Adapted slightly from here:
class MyClass
{
static void Main(string[] args)
{
string sInput, sRegex;
// The string to search.
sInput = "123456789";
// The regular expression.
sRegex = "[0-9][0-9][0-9]";
Regex r = new Regex(sRegex);
MyClass c = new MyClass();
// Assign the replace method to the MatchEvaluator delegate.
MatchEvaluator myEvaluator = new MatchEvaluator(c.ReplaceNums);
// Replace matched characters using the delegate method.
sInput = r.Replace(sInput, myEvaluator);
// Write out the modified string.
Console.WriteLine(sInput);
}
public string ReplaceNums(Match m)
// Replace each Regex match with match + " "
{
return m.ToString()+" ";
}
}
How's that?
It's been ages since I used C# and I can't test, but this may work as a one-liner which may be "neater" if you only need it once:
sInput = Regex("[0-9][0-9][0-9]").Replace(sInput,MatchEvaluator(Match m => m.ToString()+" "));
There is no way to do what you want unless you parse the string first.
Based on your comments, you only really need a simple formatting so you are better off just implementing a small helper method and thats it. (IMHO it's not really a good idea to parse the string if it isn't logically a number; you can't really be sure that in the future the input string might not be a number at all.
I'd go for something similar to:
public static string Group(this string s, int groupSize = 3, char groupSeparator = ' ')
{
var formattedIdentifierBuilder = new StringBuilder();
for (int i = 0; i < s.Length; i++)
{
if (i != 0 && (s.Length - i) % groupSize == 0)
{
formattedIdentifierBuilder.Append(groupSeparator);
}
formattedIdentifierBuilder.Append(s[i]);
}
return formattedIdentifierBuilder.ToString();
}
EDIT: Generalized to generic grouping size and group separator.
The problem is that # is a Digit placeholder and it is specific to numeric formatting only. Hence, you can't use this on strings.
Either parse the string to a numeric, so the formatting rules apply, or use other methods to split the string in two.
string.Format("{0:### ###}", int.Parse("123456"));
I need to locate a specific part of a string value like the one below, I need to alter the "Meeting ID" to a specific number.
This number comes from a dropdownlist of multiple numbers, so I cant simply use find & replace. As the text could change to one of multiple numbers before the user is happy.
The "0783," part of the string never changes, and "Meeting ID" is always followed by a ",".
So i need to get to "0783, INSERT TEXT ," and then insert the new number on the Index Changed event.
Here is an example :-
Business Invitation, start time, M Problem, 518-06-xxx, 9999 999
0783, Meeting ID, xxx ??
What is the best way of locating this string and replacing the test each time?
I hope this makes sense guys?
Okay, so there are several ways of doing this, however this seems to be a string you have control over so I'm going to say here's what you want to do.
var myString = string.Format("Business Invitation, start time, M Problem, 518-06-xxx, 9999 999 0783, {0}, xxx ??", yourMeetingId);
If you don't have control over it then you're going to have to be a bit more clever:
var startingIndex = myString.IndexOf("0783, ");
var endingIndex = myString.IndexOf(",", startingIndex + 6);
var pattern = myString.Substring(startingIndex + 6, endingIndex - (startingIndex + 6));
myString = myString.Replace(pattern, yourMeetingId);
You should store your "current" Meeting ID in a variable, changing it along with your user's actions, and then use that same global variable whenever you need the string.
This way, you don't have to worry about what's inside the string and don't need to mess with array indexes. You will also be safe from magic numbers / strings, which are bound to blow up in your face at some point in the future.
You can try with Regex.Replace method
string pattern = #"\d{3},";
Regex regex = new Regex(pattern);
var inputStr = "518-06-xxx, 9999 999 0783";
var replace = "..."
var outputStr = regex.Replace(inputStr, replace);
use Regex.Split by token "0783," then in the second string in the array return split by token "," the first element in the string array would be where you would insert new text. Then use string.Join to join the first split with "0783," and the join the second with ",".
string temp = "Business Invitation, start time, M Problem, 518-06-xxx, 9999 999 0783, Meeting ID, xxx ??";
string newID = "1234";
string[] firstSplits = Regex.Split(temp, "0783,");
string[] secondSplits = Regex.Split(firstSplits[1], ",");
secondSplits[0] = newID;
string #join = string.Join(",", secondSplits);
firstSplits[1] = #join;
string newString = string.Join("0783,", firstSplits);
I have a string which consists of different fields. So what I want to do is get the different text and assign each of them into a field.
ex: Hello Allan IBM
so what I want to do is:
put these three words in different strings like
string Greeting = "Hello"
string Name = "Allan"
string Company = "IBM"
//all of it happening in a loop.
string data = "Hello Allan IBM"
string s = data[i].ToString();
string[] words = s.Split(',');
foreach (string word in words) {
Console.WriteLine(word);
}
any suggestions?
thanks hope to hear from you soon
If I understand correctly you have a string with place-holders and you want to put different string in those place-holders:
var format="{0}, {1} {2}. How are you?";
//string Greeting = "Hello"
//string Name = "Allan"
//string Company = "IBM"
//all of it happening in a loop.
string data = ...; //I think you have an array of strings separated by ,
foreach( va s in data){
{
//string s = data[i];//.ToString(); - it is already a string array
string[] words = data[i].Split(',');
Console.WriteLine(format, words[0], words[1], words[2]);
}
To me it sound not like a problem that can be solved with a loop. The essential problem is that the loop can only work if you do exactly the same operation on the items within the loop. If your problem doesn't fit, you end up with a dozen of lines of code within the loop to handle special cases, what could have been written in a shorter way without a loop.
If there are only two or three strings you have to set (what should be the case if you have named variables), assign them from the indexes of the split string. An alternative would be using regular expressions to match some patterns to make it more robust, if one of the expected strings is missing.
Another possibility would be to set attributes on members or properties like:
[MyParseAttribute(/*position*/ /*regex*/)]
string Greeting {get;set;}
And use reflexion to populate them. Here you could create a loop on all properties having that attribute, as it sounds to me that you are eager to create a loop :-)