Go Systems Programming

Finding the number of occurrences

A very common programming problem is finding out the number of times an IP address appears in a log file. So, the example in this subsection will show you how to do this using a handy map structure. The occurrences.go program will be presented in three parts.

The first part is as follows:

package main 
 
import ( 
   "fmt" 
   "strings" 
) 
 
func main() { 
 
   var s [3]string 
   s[0] = "1 b 3 1 a a b" 
   s[1] = "11 a 1 1 1 1 a a" 
   s[2] = "-1 b 1 -4 a 1" 

The second part is as follows:

   counts := make(map[string]int) 
 
   for i := 0; i < len(s); i++ { 
         data := strings.Fields(s[i]) 
         for _, word := range data { 
               _, ok := counts[word] 
               if ok { 
                     counts[word] = counts[word] + 1 
               } else { 
                     counts[word] = 1 
               } 
         } 
   } 

Here, we use the knowledge from the ...