Extracting substrings in Go

Question

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   input    src ReadString   n   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 - gt  string but I m looking more for elegant string manipulation

User · Accepted Answer

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  inputFmt  input  len input -1

User · Answer

Go strings are not null terminated  and to remove the last char of a string you can simply do   s   s  len s -1

User · Answer

To get substring   find position of  sp  cut string with array-logical   https   play golang org p 0Redd qiZM

User · Answer

WARNING  operating on strings alone will only work with ASCII and will count wrong when input is a non-ASCII UTF-8 encoded character  and will probably even corrupt characters since it cuts multibyte chars mid-sequence  Here s a UTF-8-aware version     NOTE  this isn t multi-Unicode-codepoint aware  like specifying skintone or          gender of an emoji  https   unicode org emoji charts full-emoji-modifiers html func substr input string  start int  length int  string       asRunes      rune input           if start  gt   len asRunes            return  quot  quot                 if start length  gt  len asRunes            length   len asRunes  - start                return string asRunes start   start length

User · Answer

To avoid a panic on a zero length input  wrap the truncate operation in an if  input       src ReadString   n   var inputFmt string if len input   gt  0       inputFmt   input  len input -1       Do something with inputFmt

User · Answer

8 years later I stumbled upon this gem  and yet I don t believe  OP s original question was really answered      so I came up with the following code to trim the newline character   While the bufio Reader type supports a ReadLine    method which both removes  r n and  n it is meant as a low-level function which is awkward to use because repeated checks are necessary   IMO an idiomatic way to remove whitespace is to use Golang s strings library   input      src ReadString   n       more specific to the problem of trailing newlines actual   strings TrimRight input    r n       or if you don t mind to trim leading and trailing whitespaces  actual    strings TrimSpace input    See this example in action in the Golang playground  https   play golang org p HrOWH0kl3Ww

User · Answer

This is the simple one to perform substring in Go  package main  import  fmt   var p   fmt Println  func main        value     address bar        Take substring from index 2 to length of string   substring    value 2 len value     p substring

[go] Extracting substrings in Go

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