参考 String

String

A sequence of text characters.

The String data type is helpful for working with text. For example, a string could contain a welcome message:

// Use a string literal.
text('Hello!', 10, 10);
// Create a string variable.
let message = 'Hello!';

// Use the string variable.
text(message, 10, 10);

The most common way to create strings is to use some form of quotations as follows:

text("hi", 50, 50);
text('hi', 50, 50);
text(`hi`, 50, 50);

"hi", 'hi', and hi are all string literals. A "literal" means a value was actually written, as in text('hi', 50, 50). By contrast, text(message, 50, 50) uses the variable message, so it isn't a string literal.

Single quotes '' and double quotes "" mean the same thing. It's nice to have the option for cases when a string contains one type of quote:

text("What's up?", 50, 50);
text('Air quotes make you look "cool."', 50, 50);

Backticks `` create template literals. Template literals have many uses. For example, they can contain both single and double quotes as needed:

text(`"Don't you forget about me"`,  10, 10);

Template literals are helpful when strings are created from variables like so:

let size = random(10, 20);
circle(50, 50, size);

text(`The circle's diameter is ${size} pixels.`,  10, 10);

The size variable's value will replace ${size} when the string is created. ${} is a placeholder for any value. That means an expression can be used, as in ${round(PI, 3)}. All of the following are valid template literals:

text(`π is about ${round(PI, 2)} pixels.`,  10, 10);
text(`It's ${mouseX < width / 2} that I'm on the left half of the canvas.`,  10, 30);

Template literals can include several variables:

let x = random(0, 100);
let y = random(0, 100);
let size = random(10, 20);
circle(x, y, size);

text(`The circle at (${x}, ${y}) has a diameter of ${size} pixels.`,  10, 10);

Template literals are also helpful for creating multi-line text like so:

let poem = `My sketch doesn't run;
it waits for me patiently
while bugs point the way.`;

text(poem, 10, 10);

示例

Notice any errors or typos? Please let us know. Please feel free to edit src/core/reference.js and open a pull request!

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