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Conversion of Characters and Strings
Characters and strings may be converted into each other and into
integers. `format' and `prin1-to-string' (Note: Output Functions.)
may also be used to convert Lisp objects into strings.
`read-from-string' (Note: Input Functions.) may be used to "convert"
a string representation of a Lisp object into an object.
Note: Documentation, for a description of functions which return a
string representing the Emacs standard notation of the argument
character (`single-key-description' and `text-char-description').
These functions are used primarily for printing help messages.
- Function: char-to-string CHARACTER
This function returns a new string with a length of one character.
The value of CHARACTER, modulo 256, is used to initialize the
element of the string.
This function is similar to `make-string' with an integer argument
of 1. (Note: Creating Strings.) This conversion can also be
done with `format' using the `%c' format specification. (*Note
(char-to-string (+ 256 ?x))
(make-string 1 ?x)
- Function: string-to-char STRING
This function returns the first character in STRING. If the
string is empty, the function returns 0. The value is also 0 when
the first character of STRING is the null character, ASCII code 0.
This function may be eliminated in the future if it does not seem
useful enough to retain.
- Function: number-to-string NUMBER
- Function: int-to-string NUMBER
This function returns a string consisting of the printed
representation of NUMBER, which may be an integer or a floating
point number. The value starts with a sign if the argument is
See also the function `format' in Note: Formatting Strings.
- Function: string-to-number STRING
- Function: string-to-int STRING
This function returns the integer value of the characters in
STRING, read as a number in base ten. It skips spaces at the
beginning of STRING, then reads as much of STRING as it can
interpret as a number. (On some systems it ignores other
whitespace at the beginning, not just spaces.) If the first
character after the ignored whitespace is not a digit or a minus
sign, this function returns 0.
(string-to-number "25 is a perfect square.")
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