如何在Golang中的其他目录中重命名一组文件

Question

I made a program in Python 2.7 that renames the files in a directory by replacing the numbers in those file names. I tried to do the same thing with a Golang app but it is not working. The console still gives be new names but it is not changing the names of the photos in the file directory.

Here is the python program

import os
def rename_files():
    #(1) get files names from a folder
    file_list = os.listdir(r"C:\\Users\\g\\Desktop\\Fun\\udacity\\foundationsofpython\\07finalrenamingapp\\prank")
    print(file_list)
    saved_path = os.getcwd()
    print (saved_path)
    os.chdir(r"C:\\Users\\g\\Desktop\\Fun\\udacity\\foundationsofpython\\07finalrenamingapp\\prank")

    #2 rename all files names in folder
    for file_name in file_list:
        print ("Old Name - " +file_name)
        print ("New Name - " +file_name.strip("0123456789"))
        os.rename(file_name,file_name.strip("0123456789"))
    os.chdir(saved_path)

rename_files()

This works just fine. However, this Golang script does not This is the Golang program

package main

import (
    "log"
    "os"
    "fmt"
    "regexp"
)
func readCurrentDir() {
    dir := "C:\\Users\\g\\Desktop\\prank"
    file, err := os.Open(dir)
    if err != nil {
        log.Fatalf("failed opening directory: %s", err)
    }
    defer file.Close()

    list,_ := file.Readdirnames(0) // 0 to read all files and folders
    for _, name := range list {
        oldName := name
        fmt.Println("Old Name - ", oldName)
        re := regexp.MustCompile( "[^A-za-z]" )
        newName := re.ReplaceAllString( oldName, " ")
        fmt.Println("New Name - ", newName)        
        os.Rename(dir+oldName, dir+newName)
        fmt.Println("File names have been changed")

    }
}

func main() {
    readCurrentDir()

}

If you want to pull these to projects from the github repo here is a link that will provide you with the code and the photo folder where the images are stored. I would benefit the most by seeing where my code needs to be changed. Any help or advice you could give would be greatly appreciated. Thank you very much.

Python App https://github.com/lashleykeith/GoingwithGolang/tree/master/OldCode2BeChanged

Golang App https://github.com/lashleykeith/GoingwithGolang/tree/master/our_tutorial/5finalrenamingapp

Answer 1

In Go, always, always, check for errors. Many of your problems will then be obvious. For example, you have os.Rename errors.

Use the filepath package to manipulate filename paths. Compiling a constant regex expression should only be done once. Fix your regexp bug: "[^A-za-z]" should be "[^A-Za-z]".

Here's a working version:

package main

import (
    "fmt"
    "log"
    "os"
    "path/filepath"
    "regexp"
)

func readCurrentDir() {
    dir := "C:\\Users\\g\\Desktop\\prank"
    file, err := os.Open(dir)
    if err != nil {
        log.Fatalf("failed opening directory: %s", err)
    }
    defer file.Close()

    list, err := file.Readdirnames(0) // 0 to read all files and folders
    if err != nil {
        log.Fatalf("failed reading directory: %s", err)
    }
    re := regexp.MustCompile("[^A-Za-z]")
    for _, name := range list {
        oldName := name
        fmt.Println("Old Name - ", oldName)
        newName := re.ReplaceAllString(oldName, " ")
        fmt.Println("New Name - ", newName)
        err := os.Rename(filepath.Join(dir, oldName), filepath.Join(dir, newName))
        if err != nil {
            log.Printf("error renaming file: %s", err)
            continue
        }
        fmt.Println("File names have been changed")
    }
}

func main() {
    readCurrentDir()
}

Output:

Old Name -  prankster.42.txt
New Name -  prankster    txt
File names have been changed

Diff:

> git diff old.go new.go
diff --git a/old.go b/new.go
index 464b60e..7ae276e 100644
--- a/old.go
+++ b/new.go
@@ -4,6 +4,7 @@ import (
        "fmt"
        "log"
        "os"
+       "path/filepath"
        "regexp"
 )

@@ -15,69 +16,31 @@ func readCurrentDir() {
        }
        defer file.Close()

-       list, _ := file.Readdirnames(0) // 0 to read all files and folders
+       list, err := file.Readdirnames(0) // 0 to read all files and folders
+       if err != nil {
+               log.Fatalf("failed reading directory: %s", err)
+       }
+       re := regexp.MustCompile("[^A-Za-z]")
        for _, name := range list {
                oldName := name
                fmt.Println("Old Name - ", oldName)
-               re := regexp.MustCompile("[^A-za-z]")
                newName := re.ReplaceAllString(oldName, " ")
                fmt.Println("New Name - ", newName)
-               os.Rename(dir+oldName, dir+newName)
+               err := os.Rename(filepath.Join(dir, oldName), filepath.Join(dir, newName))
+               if err != nil {
+                       log.Printf("error renaming file: %s", err)
+                       continue
+               }
                fmt.Println("File names have been changed")
-
        }
 }

 func main() {
        readCurrentDir()
-
 }
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