Number vs. String

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Question: Is there a way to test whether a particular variable holds a number or a string?

Answer: Yes. To test whether the variable holds a number or a string, use the

typeof
operator. If your variable holds a number,
typeof(variable)
will return
"number"
. If it holds a string,
typeof(variable)
will return
"string"
. The following are examples of
typeof
usage:
typeof(123)    // result: "number"
typeof("123")  // result: "string"

if (typeof k == "string") { alert('k is a string.') }
if (typeof k == "number") { alert('k is a number.') }
The
typeof
operator can also help you distinguish between other data types. Depending on the particular variable's value, the result of
typeof
can be one of the following:
"number"

"string"

"boolean"

"function"

"object"

"undefined"

See also:

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