Word count

Sometimes a document may have a certain file size, but the word count is clearer for estimating its length. A function that counts words in Swift can be developed.

With a for-loop over the characters, we can test each character with Character type properties. Some logic is required to test for whitespace.

Example

We introduce the countWords function. This function receives a String and returns an Int—the count of words in the string.

func countWords(source: String) -> Int {
    var count = 0
    var previous: Character = " "
    // Step 1: loop over string characters.
    for c in source {
        // Step 2: test previous character for whitespace, and current for letter, number or punctuation.
        if previous.isWhitespace {
            if c.isLetter || c.isNumber || c.isPunctuation {
                count += 1
            }
        }
        // Step 3: set previous.
        previous = c
    }
    // Step 4: return count of words.
    return count
}

// Use word counting function.
let input = "Cat, bird and dog."
let result = countWords(source: input)
print(result)
4

It is possible to develop an iterative word count algorithm in Swift, and this gives accurate results for English. It is also fast, as no regular expressions are used.