Extracting substrings in Go

mark2222 picture mark2222 · Sep 7, 2012 · Viewed 162.8k times · Source

I'm trying to read an entire line from the console (including whitespace), then process it. Using bufio.ReadString, the newline character is read together with the input, so I came up with the following code to trim the newline character:

inputFmt:=input[0:len(input)-2]+"" //Need to manually add end of string

Is there a more idiomatic way to do this? That is, is there already a library that takes care of the ending null byte when extracting substrings for you?

(Yes, I know there is already a way to read a line without the newline character in go readline -> string but I'm looking more for elegant string manipulation.)


Denys Séguret picture Denys Séguret · Sep 7, 2012

It looks like you're confused by the working of slices and the string storage format, which is different from what you have in C.

  • any slice in Go stores the length (in bytes), so you don't have to care about the cost of the len operation : there is no need to count
  • Go strings aren't null terminated, so you don't have to remove a null byte, and you don't have to add 1 after slicing by adding an empty string.

To remove the last char (if it's a one byte char), simply do