convert hex string to number

[Glen Rubin]

Hi!

I am working with a sequence of hex numbers that are in string format,

e.g.

("0x34" "0xff" "0x01" ...)

Is there a function for converting these strings into normal hex or
numbers?? I tried num, but it didn't work.

Thanks!

[Richard Newman]

> Is there a function for converting these strings into normal hex or
> numbers?? I tried num, but it didn't work.

user=> (read-string "0x44")
68

Safer:

(defn hex->num [#^String s]
(binding [*read-eval* false]
(let [n (read-string s)]
(when (number? n)
n))))

You could also use parseInt, which will be faster, so long as you can
guarantee the format:

(defn hex->num [#^String s]
(Integer/parseInt (.substring s 2) 16))

[Glen Rubin]

thanks...you rock!!

[Luc Prefontaine]

Use a try catch around parseInt to report bad hex nb formats.
At least you'll know if you are feedind
odd values to your hex function.

Luc

Sent from my iPod

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