Turn string into number in Racket

问题:

I used read to get a line from a file. The documentation said read returns any, so is it turning the line to a string? I have problems turning the string "1" to the number 1, or "500.8232" into 500.8232. I am also wondering if Racket can directly read numbers in from a file.

回答1:

Check out their documentation search, it's complete and accurate. Conversion functions usually have the form of foo->bar (which you can assume takes a foo and returns a bar constructed from it).

You sound like you're looking for a function that takes a string and returns a number, and as it happens, string->number does exist, and does pretty much exactly what you're looking for.

回答2:

Looks like this was answered in another question:

Convert String to Code in Scheme

NB: that converts any s-expression, not just integers. If you want just integers, try:

string->number

Which is mentioned in

Scheme language: merge two numbers

HTH