Extract the first and last characters from a string.

← Operators and Expressions · Ref: Q1166

Use the prefix (#<) and suffix (#>) operators:

  firstChar <- #< name
  lastChar <- #> name

The #< operator returns the first character (as a Character) and #> returns the last character. These are introspection operators available on String. See Q242 for conversion and introspection operators. See Q238 for the complete operator set.

Example

defines module qa.operators.substringextract

  defines program

    SubstringExtractDemo()
      stdout <- Stdout()

      name <- "Hello"

      // Extract first and last characters
      firstChar <- #< name
      lastChar <- #> name
      stdout.println(`First: ${firstChar}`)
      stdout.println(`Last: ${lastChar}`)

      // Use with different strings
      words <- ["EK9", "World", "A"]
      for word in words
        first <- #< word
        last <- #> word
        stdout.println(`'${word}' -> first: ${first}, last: ${last}`)

      // Length for context
      size <- length name
      stdout.println(`Length of '${name}': ${size}`)

Common mistakes

E50060 — String has no charAt() method. Use the #< prefix operator to get the first character and #> suffix operator for the last character. See ek9 -h E50060 for details.

Incorrect:

firstChar <- name.charAt(0)

Correct:

firstChar <- #< name

Coming from another language?

Java: str.charAt(0) and str.charAt(str.length()-1). Python: str[0] and str[-1]. Rust: str.chars().next() and str.chars().last(). Go: str[0] and str[len(str)-1]. EK9: #< str and #> str — prefix and suffix operators.

Keywords: prefix, first, last, extract, character, suffix, introspection, operator, string