1.4.4 Characters
| (alpha-char-p x) → t |
| x : (characterp x) |
Determines whether x is an alphabetic character.
Examples: |
| > (alpha-char-p #\a) |
t |
| > (alpha-char-p #\3) |
() |
| (char str n) → t |
| str : (stringp str) |
| n : (and (integerp n) (>= n 0) (< n (length str))) |
Extracts the character at the nth (0-based) position in the string str.
Examples: |
| > (char "hello" 0) |
#\h |
| > (char "hello" 4) |
#\o |
| (char< x y) → t |
| x : (characterp x) |
| y : (characterp y) |
Determines whether the character code of x is less than that of y.
Examples: |
| > (char< #\a #\b) |
t |
| > (char< #\b #\a) |
() |
| > (char< #\b #\b) |
() |
| > (char< #\A #\a) |
t |
| (char<= x y) → t |
| x : (characterp x) |
| y : (characterp y) |
Determines whether the character code of x is less than or equal to that of y.
Examples: |
| > (char<= #\a #\b) |
t |
| > (char<= #\b #\a) |
() |
| > (char<= #\b #\b) |
t |
| > (char<= #\A #\a) |
t |
| (char> x y) → t |
| x : (characterp x) |
| y : (characterp y) |
Determines whether the character code of x is greater than that of y.
Examples: |
| > (char> #\a #\b) |
() |
| > (char> #\b #\a) |
t |
| > (char> #\b #\b) |
() |
| > (char> #\A #\a) |
() |
| (char>= x y) → t |
| x : (characterp x) |
| y : (characterp y) |
Determines whether the character code of x is greater than or equal to that of y.
Examples: |
| > (char>= #\a #\b) |
() |
| > (char>= #\b #\a) |
t |
| > (char>= #\b #\b) |
t |
| > (char>= #\A #\a) |
() |
| (char-code char) → t |
| char : (characterp char) |
Returns the numeric code for the given character.
Examples: |
| > (char-code #\a) |
97 |
| > (char-code #\Z) |
90 |
| (char-downcase char) → t |
| char : (and (characterp char) (standard-char-p str)) |
Converts the given character to lowercase
Examples: |
| > (char-downcase #\A) |
#\a |
| > (char-downcase #\a) |
#\a |
| (char-equal x y) → t |
| x : (and (characterp x) (standard-char-p x)) |
| y : (and (characterp y) (standard-char-p y)) |
Checks if the given characters are equal, ignoring to case.
Examples: |
| > (char-equal #\a #\a) |
t |
| > (char-equal #\A #\a) |
t |
| (char-upcase char) → t |
| char : (and (characterp char) (standard-char-p str)) |
Converts the given character to uppercase
Examples: |
| > (char-upcase #\A) |
#\A |
| > (char-upcase #\a) |
#\A |
| (characterp x) |
Examples: |
| > (characterp #\a) |
t |
| > (characterp "a") |
() |
| (code-char x) → t |
| x : (and (integerp x) (>= x 0) (< x 256)) |
Converts the given number into its character equivalent.
Examples: |
| > (code-char 0) |
#\nul |
| > (code-char 97) |
#\a |
| > (code-char 255) |
#\ÿ |
| > (code-char 1000) |
#\Ϩ |
| (digit-char-p x) → t |
| x : (characterp x) |
Determines whether the given character represents a numerical digit.
Examples: |
| > (digit-char-p #\3) |
3 |
| > (digit-char-p #\a) |
() |
| (digit-to-char n) → t |
| n : (and (integerp n) (<= 0 n) (>= 15 n)) |
Converts the given number into its equivalent character in hex notation.
Examples: |
| > (digit-to-char 7) |
#\7 |
| > (digit-to-char 10) |
#\A |
| > (digit-to-char 15) |
#\F |
| (lower-case-p [x (and (characterp x) (standard-char-p x))]) |
#<procedure:t>Determines if x is a lowercase alphabetic character.
Examples: |
| > (lower-case-p #\a) |
t |
| > (lower-case-p #\A) |
() |
| (standard-char-p x) → t |
| x : (characterp x) |
Checks if the given character is a member of the *standard-chars*. This includes the standard punctuation and alphanumeric characters, along with #\newline and #\space.
Examples: |
| > (standard-char-p #\a) |
t |
| > (standard-char-p #\5) |
t |
| > (standard-char-p #\tab) |
() |
| (upper-case-p x) → t |
| x : (and (characterp x) (standard-char-p x)) |
Determines if x is an upper-case alphabetic character.
Examples: |
| > (upper-case-p #\A) |
t |
| > (upper-case-p #\a) |
() |