diff --git a/examples.txt b/examples.txt index d4859d3..91a1fde 100644 --- a/examples.txt +++ b/examples.txt @@ -57,6 +57,7 @@ Base64 Encoding Reading Files Writing Files Line Filters +File Paths Command-Line Arguments Command-Line Flags Command-Line Subcommands diff --git a/examples/file-paths/file-paths.go b/examples/file-paths/file-paths.go new file mode 100644 index 0000000..75b017d --- /dev/null +++ b/examples/file-paths/file-paths.go @@ -0,0 +1,62 @@ +// The `filepath` package provides functions to parse +// and construct *file paths* in a way that is portable +// between operating systems; `dir/file` on Linux vs. +// `dir\file` on Windows, for example. +package main + +import ( + "fmt" + "path/filepath" + "strings" +) + +func main() { + + // `Join` should be used to construct paths in a + // portable way. It takes any number of arguments + // and constructs a hierarchical path from them. + p := filepath.Join("dir1", "dir2", "filename") + fmt.Println("p:", p) + + // You should always use `Join` instead of + // concatenating `/`s or `\`s manually. In addition + // to providing portability, `Join` will also + // normalize paths by removing superfluous separators + // and directory changes. + fmt.Println(filepath.Join("dir1//", "filename")) + fmt.Println(filepath.Join("dir1/../dir1", "filename")) + + // `Dir` and `Base` can be used to split a path to the + // directory and the file. Alternatively, `Split` will + // return both in the same call. + fmt.Println("Dir(p):", filepath.Dir(p)) + fmt.Println("Base(p):", filepath.Base(p)) + + // To check whether a path is absolute, use `IsAbs`. + fmt.Println(filepath.IsAbs("dir/file")) + fmt.Println(filepath.IsAbs("/dir/file")) + + filename := "config.json" + + // To find a file's extension, use `Ext`. + ext := filepath.Ext(filename) + fmt.Println(ext) + + // To find the file's name with the extension removed, + // use `TrimSuffix`. + fmt.Println(strings.TrimSuffix(filename, ext)) + + // `Rel` finds a relative path between a *base* and a + // *target*. + rel, err := filepath.Rel("a/b", "a/b/t/file") + if err != nil { + panic(err) + } + fmt.Println(rel) + + rel, err = filepath.Rel("a/b", "a/c/t/file") + if err != nil { + panic(err) + } + fmt.Println(rel) +} diff --git a/examples/file-paths/file-paths.hash b/examples/file-paths/file-paths.hash new file mode 100644 index 0000000..7cc06ab --- /dev/null +++ b/examples/file-paths/file-paths.hash @@ -0,0 +1,2 @@ +4611ff69626490eb50673a739707d870fac79142 +eUhAltl7_sI diff --git a/examples/file-paths/file-paths.sh b/examples/file-paths/file-paths.sh new file mode 100644 index 0000000..4ef4251 --- /dev/null +++ b/examples/file-paths/file-paths.sh @@ -0,0 +1,12 @@ +$ go run file-paths.go +p: dir1/dir2/filename +dir1/filename +dir1/filename +Dir(p): dir1/dir2 +Base(p): filename +false +true +.json +config +t/file +../c/t/file diff --git a/public/file-paths b/public/file-paths new file mode 100644 index 0000000..9085662 --- /dev/null +++ b/public/file-paths @@ -0,0 +1,238 @@ + + + + + Go by Example: File Paths + + + +
+

Go by Example: File Paths

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

The filepath package provides functions to parse +and construct file paths in a way that is portable +between operating systems; dir/file on Linux vs. +dir\file on Windows, for example.

+ + 		+ + + + 
package main
+
+ +
+ + + + 
import (
+    "fmt"
+    "path/filepath"
+    "strings"
+)
+
+ +
+ + + + 
func main() {
+
+ +
+

Join should be used to construct paths in a +portable way. It takes any number of arguments +and constructs a hierarchical path from them.

+ + 		+ + 
    p := filepath.Join("dir1", "dir2", "filename")
+    fmt.Println("p:", p)
+
+ +
+

You should always use Join instead of +concatenating /s or \s manually. In addition +to providing portability, Join will also +normalize paths by removing superfluous separators +and directory changes.

+ + 		+ + 
    fmt.Println(filepath.Join("dir1//", "filename"))
+    fmt.Println(filepath.Join("dir1/../dir1", "filename"))
+
+ +
+

Dir and Base can be used to split a path to the +directory and the file. Alternatively, Split will +return both in the same call.

+ + 		+ + 
    fmt.Println("Dir(p):", filepath.Dir(p))
+    fmt.Println("Base(p):", filepath.Base(p))
+
+ +
+

To check whether a path is absolute, use IsAbs.

+ + 		+ + 
    fmt.Println(filepath.IsAbs("dir/file"))
+    fmt.Println(filepath.IsAbs("/dir/file"))
+
+ +
+ + + + 
    filename := "config.json"
+
+ +
+

To find a file’s extension, use Ext.

+ + 		+ + 
    ext := filepath.Ext(filename)
+    fmt.Println(ext)
+
+ +
+

To find the file’s name with the extension removed, +use TrimSuffix.

+ + 		+ + 
    fmt.Println(strings.TrimSuffix(filename, ext))
+
+ +
+

Rel finds a relative path between a base and a +target.

+ + 		+ + 
    rel, err := filepath.Rel("a/b", "a/b/t/file")
+    if err != nil {
+        panic(err)
+    }
+    fmt.Println(rel)
+
+ +
+ + + + 
    rel, err = filepath.Rel("a/b", "a/c/t/file")
+    if err != nil {
+        panic(err)
+    }
+    fmt.Println(rel)
+}
+
+ +
+ + + + + + + + +
+ + + + 
$ go run file-paths.go
+p: dir1/dir2/filename
+dir1/filename
+dir1/filename
+Dir(p): dir1/dir2
+Base(p): filename
+false
+true
+.json
+config
+t/file
+../c/t/file
+
+ +
+ + +

+ Next example: Command-Line Arguments. +

+ +

+ by Mark McGranaghan | source | license +

+
+ + diff --git a/public/index.html b/public/index.html index e3960aa..ef6fe69 100644 --- a/public/index.html +++ b/public/index.html @@ -141,6 +141,8 @@
  • Line Filters
    • +
  • File Paths
    • +
  • Command-Line Arguments
  • Command-Line Flags
    • diff --git a/public/line-filters b/public/line-filters index d1dd866..d264214 100644 --- a/public/line-filters +++ b/public/line-filters @@ -183,7 +183,7 @@ lowercase lines.

    - Next example: Command-Line Arguments. + Next example: File Paths.