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# Characters
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A Racket _character_ corresponds to a Unicode _scalar value_. Roughly, a
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scalar value is an unsigned integer whose representation fits into 21
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bits, and that maps to some notion of a natural-language character or
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piece of a character. Technically, a scalar value is a simpler notion
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than the concept called a “character” in the Unicode standard, but it’s
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an approximation that works well for many purposes. For example, any
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accented Roman letter can be represented as a scalar value, as can any
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common Chinese character.
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Although each Racket character corresponds to an integer, the character
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datatype is separate from numbers. The `char->integer` and
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`integer->char` procedures convert between scalar-value numbers and the
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corresponding character.
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A printable character normally prints as `#\` followed by the
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represented character. An unprintable character normally prints as `#\u`
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followed by the scalar value as hexadecimal number. A few characters are
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printed specially; for example, the space and linefeed characters print
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as `#\space` and `#\newline`, respectively.
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> +\[missing\] in \[missing\] documents the fine points of the syntax of
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> characters.
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Examples:
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```racket
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> (integer->char 65)
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#\A
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> (char->integer #\A)
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65
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> #\λ
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#\λ
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> #\u03BB
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#\λ
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> (integer->char 17)
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#\u0011
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> (char->integer #\space)
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32
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```
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The `display` procedure directly writes a character to the current
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output port \(see \[missing\]\), in contrast to the character-constant
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syntax used to print a character result.
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Examples:
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```racket
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> #\A
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#\A
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> (display #\A)
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A
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```
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Racket provides several classification and conversion procedures on
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characters. Beware, however, that conversions on some Unicode characters
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work as a human would expect only when they are in a string \(e.g.,
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upcasing “ß” or downcasing “Σ”\).
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Examples:
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```racket
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> (char-alphabetic? #\A)
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#t
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> (char-numeric? #\0)
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#t
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> (char-whitespace? #\newline)
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#t
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> (char-downcase #\A)
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#\a
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> (char-upcase #\ß)
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#\ß
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```
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The `char=?` procedure compares two or more characters, and `char-ci=?`
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compares characters ignoring case. The `eqv?` and `equal?` procedures
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behave the same as `char=?` on characters; use `char=?` when you want to
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more specifically declare that the values being compared are characters.
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Examples:
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```racket
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> (char=? #\a #\A)
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#f
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> (char-ci=? #\a #\A)
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#t
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> (eqv? #\a #\A)
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#f
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```
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> +\[missing\] in \[missing\] provides more on characters and character
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> procedures.
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