String Operators

  • JavaScript’s string operators are used to attach strings to one another, or to attach variables to strings.
  • String operators each have a symbol known as the operator that is used to perform the operation

1. Concatenation : concatenate is another word for add. Concatenating two strings simply means adding or attaching them to one another.

  • Operator: +
  • Examples: x = "My name is "; y = "Hulk Hogan, "; z = "Brothur"; var sentence = x + y + z;
  • Q : What is the value of the variable sentence? —
  • Note that this operator (+) is also used for numerical addition.
  • You may ask how you are supposed to specify that you are adding strings instead of numbers, and the answer is that you do not have to.
  • If any value you are adding is a string, the compiler automatically uses the + operator to concatenate values to the string, even if they are numbers. The result is a string. For example: var cents = 93; var sentenceWithNumbers = "I have " + 16 + " dollars and " + cents + " cents."; console.log(sentenceWithNumbers);
  • The result of this code in the console would be:

Image description

  • Note that between each value or variable added, another addition sign needs to be used to concatenate the entire string. —
  • It is good practice to pay attention to where spaces should be inserted so that the sentence’s formatting is not confusing and bunched together when the string is printed out.
  • Typically if you are printing a string and then a new variable or string, you want to make sure there is a space included at the end of the first string, or the beginning of the second.

  • If a numeric value is printed before another or before a string, you can concatenate a single space before the next number, or include a space in the beginning of the next string

    2. Concatenate-Equals : assigning a variable to its original value plus some specified value concatenated to it

  • Operator: +=

  • Examples:

    x = "My name is ";
y = "Hulk Hogan,";
z = "Brothur";
var sentence = x + y + z;
x += y + z;

  • Q : What is the value of variable x? Is this equal to the value of sentence?

Exercise 2.3

See the Pen Exercise 2.3 by LSU DDEM (@lsuddem) on CodePen.