First show how to readlines from URL , and then extend to read
lines from file and string .
url.go |
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29 package lines
import (
"bufio"
"io"
"net/http"
)
func UrlToLines ( url string ) ([] string , error ) {
resp , err := http . Get ( url )
if err != nil {
return nil , err
}
defer resp . Body . Close ()
return LinesFromReader ( resp . Body )
}
func LinesFromReader ( r io . Reader ) ([] string , error ) {
var lines [] string
scanner := bufio . NewScanner ( r )
for scanner . Scan () {
lines = append ( lines , scanner . Text ())
}
if err := scanner . Err (); err != nil {
return nil , err
}
return lines , nil
}
Note that LinesFromReader func accepts argument of io.Reader , which is an
interface . Later this function will be re-used to read lines from file/string.
Usage of UrlToLines :
url_test.go |
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14 package lines
import "testing"
func TestUrlToLines ( t * testing . T ) {
lines , err := UrlToLines ( "https://raw.githubusercontent.com/siongui/userpages/master/README.rst" )
if err != nil {
t . Error ( err )
}
for _ , line := range lines {
println ( line )
}
}
Use the following code with the LinesFromReader func in the previous section,
we can read a file line by line:
file.go |
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12 package lines
import "os"
func FileToLines ( filePath string ) ([] string , error ) {
f , err := os . Open ( filePath )
if err != nil {
return nil , err
}
defer f . Close ()
return LinesFromReader ( f )
}
Usage of FileToLines :
file_test.go |
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14 package lines
import "testing"
func TestFileToLines ( t * testing . T ) {
lines , err := FileToLines ( "file.go" )
if err != nil {
t . Error ( err )
}
for _ , line := range lines {
println ( line )
}
}
Use the following code with the LinesFromReader func in the previous section,
we can read a string line by line:
string.go |
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package lines
import "strings"
func StringToLines ( s string ) ([] string , error ) {
r := strings . NewReader ( s )
return LinesFromReader ( r )
}
Usage of StringToLines :
string_test.go |
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15 package lines
import "testing"
func TestStringToLines ( t * testing . T ) {
str := "hello\nworld\n"
lines , err := StringToLines ( str )
if err != nil {
t . Error ( err )
}
for _ , line := range lines {
println ( line )
}
}
Tested on:
Ubuntu Linux 16.10 Go 1.7.5
References: