Is there any solution which can identify that a string is a number or character

Is there any solution which can identify that a string is a number or a
character?
for example:

"89.56" <--> "get"
how to tell the differecnces of that

thanks
homling

 

(numberp) should tell you if it is a real or integer.

--

Regards,

Ian A. White, CPEng

WAI Engineering
Sydney 2000
Australia

Ph: +61 418 203 229
Fax: +61 2 9622 0450
Home Page: www.wai.com.au

 

Command: (numberp (distof "get"))
nil

Command: (numberp (distof "89.56"))
T

 

Herman,

Just for fun. Does this work as well?

;; lacks data type check
;; returns nil or number
(defun test_str2num (str)
(if (= "." (substr str 1 1))
(setq str (strcat "0" str)))
(if (numberp (read str))
(read str))
)

The reason for (strcat "0" str) is read chokes on (read ".01") with "misplaced
dot on input".

Joe Burke

 

Joe,

for more fun.....<g>

(setq str ".01")

(distof str)

returns 0.01

--
Ken Alexander
Acad2000
Windows2000 Prof.

"We can't solve problems by using the same kind
of thinking we used when we created them."
--Albert Einstein

 

Another possibility...

Command: (setq str "fred")
"fred"

Command: (type (read str))
SYM

Command: (setq str "0.01")
"0.01"

Command: (type (read str))
REAL

Command: (setq str "1")
"1"

Command: (type (read str))
INT

Just compare the results of SYM REAL or INT

Don

 

Ken,

Interesting. Should (read ".01") not error, or is it just being literal? As if
we have any choice in the matter.

Command: (distof "1")
1.0
Command: (str2num "1")
1

Joe Burke

 

Herman.

Got it and thanks. I might rename it, "maybenum2num".

Joe Burke