Golang : Pad file extension automagically

Problem: You want to pad file type extension to a given filename string without prompting your program users to do so. Your program accepts extension of certain type only. How to pad the missing file type extension automatically? Solution: Use strings.HasSuffix() function to detect if the filename string has the file type extension. If not, pad the filename string with the file extension type. Here you go! package main import ( "strings" "os" "fmt" ) func main() { if len(os.Args) != 2 { fmt.Printf("Usage : %s <filename.ext>\n", os.Args[0]) os.Exit(0) } inputFileName := os.Args[1] fmt.Println("Input file name is : ", inputFileName) if !strings.HasSuffix(inputFileName, ".ext") { // check if the .ext is in the string fmt.Println("Input file name does not have extension. Padding now") inputFileName += ".ext" fmt.Println("Input file name with extension padded : ", inputFileName) } else { fmt.Println("Input file name already has extension : ", inputFileName) } } Sample outputs: ./padfileextent testfilenamewithoutextension.bmp Input file name is : testfilenamewithoutextension.bmp Input file name does not have extension. Padding now Input file name with extension padded : testfilenamewithoutextension.bmp.ext NOTE : Still pad with .ext because the filename does not have the required extension ./padfileextent testfilenamewithoutextension Input file name is : testfilenamewithoutextension Input file name does not have extension. Padding now Input file name with extension padded : testfilenamewithoutextension.ext ./padfileextent testfilenamewithoutextension.ext Input file name is : testfilenamewithoutextension.ext Input file name already has extension : testfilenamewithoutextension.ext References: https://www.socketloop.com/tutorials/golang-get-command-line-arguments

Tags : golang pad-file-extension filename strings-hassuffix

Adam Ng By Adam Ng

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