In Clojure how can I convert a String to a number?

Question

I have various strings, some like \"45\", some like \"45px\". How how I convert both of these to the number 45?

Answer 1

Expanding on snrobot's answer:

(defn string->integer [s] 
  (when-let [d (re-find #"-?\d+" s)] (Integer. d)))

This versions returns nil if there are no digits in the input, rather than raising an exception.

My question is whether it's acceptable to abbreviate the name to "str->int", or if things like this should always be fully specified.