How do you print a dollar sign $ in Dart

Question

I need to actually print a Dollar sign in Dart, ahead of a variable. For example:

void main() {   int dollars=42;   print("I have $dollars."); // I have 42. } 

I want the output to be: I have $42. How can I do this? Thanks.

Answer 1

Dart strings can be either raw or ... not raw (normal? cooked? interpreted? There isn't a formal name). I'll go with "interpreted" here, because it describes the problem you have.

In a raw string, "$" and "\" mean nothing special, they are just characters like any other. In an interpreted string, "$" starts an interpolation and "\" starts an escape.

Since you want the interpolation for "$dollars", you can't use "$" literally, so you need to escape it:

int dollars = 42; print("I have \$$dollars."); 

If you don't want to use an escape, you can combine the string from raw and interpreted parts:

int dollars = 42; print(r"I have $" "$dollars.");  

Two adjacent string literals are combined into one string, even if they are different types of string.

Answer 2

You can use a backslash to escape:

int dollars=42; print("I have \$$dollars."); // I have $42. 

When you are using literals instead of variables you can also use raw strings:

print(r"I have $42."); // I have $42.