How to escape braces (curly brackets) in a format string in .NET


Question

How can brackets be escaped in using string.Format. For example:

String val = "1,2,3"
String.Format(" foo {{0}}", val); 

This example doesn't throw an exception, but outputs the string foo {0}

Is there a way to escape the brackets?

1
936
6/17/2014 9:18:00 PM

Accepted Answer

For you to output foo {1, 2, 3} you have to do something like:

string t = "1, 2, 3";
string v = String.Format(" foo {{{0}}}", t);

To output a { you use {{ and to output a } you use }}.

1233
9/4/2013 1:43:00 PM

Yes to output { in string.Format you have to escape it like this {{

So this

String val = "1,2,3";
String.Format(" foo {{{0}}}", val);

will output "foo {1,2,3}".

BUT you have to know about a design bug in C# which is that by going on the above logic you would assume this below code will print {24.00}

int i = 24;
string str = String.Format("{{{0:N}}}", i); //gives '{N}' instead of {24.00}

But this prints {N}. This is because the way C# parses escape sequences and format characters. To get the desired value in the above case you have to use this instead.

String.Format("{0}{1:N}{2}", "{", i, "}") //evaluates to {24.00}

Reference Articles String.Format gottach and String Formatting FAQ


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