How do I interpolate strings?

Question

I want to do the following in C# (coming from a Python background):

strVar = \"stack\"
mystr  = \"This is %soverflow\" % (strVar)

How do I

Answer 1

You can use string.Format to drop values into strings:

private static readonly string formatString = "This is {0}overflow";
...
var strVar = "stack";
var myStr = string.Format(formatString, "stack");

An alternative is to use the C# concatenation operator:

var strVar = "stack";
var myStr = "This is " + strVar + "overflow";

If you're doing a lot of concatenations use the StringBuilder class which is more efficient:

var strVar = "stack";
var stringBuilder = new StringBuilder("This is ");
for (;;)
{
    stringBuilder.Append(strVar); // spot the deliberate mistake ;-)
}
stringBuilder.Append("overflow");
var myStr = stringBuilder.ToString();