File Paths example

2019-06-06 06:17:45 -07:00 · 2019-06-06 06:17:45 -07:00 · 52be303a71
commit 52be303a71
parent f2802c4c93
7 changed files with 318 additions and 1 deletions
--- 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
--- a/examples/file-paths/file-paths.go
+++ 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)
+}
--- a/examples/file-paths/file-paths.hash
+++ b/examples/file-paths/file-paths.hash
@ -0,0 +1,2 @@
+4611ff69626490eb50673a739707d870fac79142
+eUhAltl7_sI
--- a/examples/file-paths/file-paths.sh
+++ 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
--- a/public/file-paths
+++ b/public/file-paths
@ -0,0 +1,238 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>Go by Example: File Paths</title>
+    <link rel=stylesheet href="site.css">
+  </head>
+  <body>
+    <div class="example" id="file-paths">
+      <h2><a href="./">Go by Example</a>: File Paths</h2>
+      
+      <table>
+        
+        <tr>
+          <td class="docs">
+            <p>The <code>filepath</code> package provides functions to parse
+and construct <em>file paths</em> in a way that is portable
+between operating systems; <code>dir/file</code> on Linux vs.
+<code>dir\file</code> on Windows, for example.</p>
+
+          </td>
+          <td class="code leading">
+            <a href="http://play.golang.org/p/eUhAltl7_sI">
+              <img title="Run code" class="run" src="data:image/png;base64,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" />
+            </a>
+            <div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
+</pre></div>
+
+          </td>
+        </tr>
+        
+        <tr>
+          <td class="docs">
+            
+          </td>
+          <td class="code leading">
+            
+            <div class="highlight"><pre><span class="kn">import</span> <span class="p">(</span>
+    <span class="s">&quot;fmt&quot;</span>
+    <span class="s">&quot;path/filepath&quot;</span>
+    <span class="s">&quot;strings&quot;</span>
+<span class="p">)</span>
+</pre></div>
+
+          </td>
+        </tr>
+        
+        <tr>
+          <td class="docs">
+            
+          </td>
+          <td class="code leading">
+            
+            <div class="highlight"><pre><span class="kd">func</span> <span class="nx">main</span><span class="p">()</span> <span class="p">{</span>
+</pre></div>
+
+          </td>
+        </tr>
+        
+        <tr>
+          <td class="docs">
+            <p><code>Join</code> should be used to construct paths in a
+portable way. It takes any number of arguments
+and constructs a hierarchical path from them.</p>
+
+          </td>
+          <td class="code leading">
+            
+            <div class="highlight"><pre>    <span class="nx">p</span> <span class="o">:=</span> <span class="nx">filepath</span><span class="p">.</span><span class="nx">Join</span><span class="p">(</span><span class="s">&quot;dir1&quot;</span><span class="p">,</span> <span class="s">&quot;dir2&quot;</span><span class="p">,</span> <span class="s">&quot;filename&quot;</span><span class="p">)</span>
+    <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="s">&quot;p:&quot;</span><span class="p">,</span> <span class="nx">p</span><span class="p">)</span>
+</pre></div>
+
+          </td>
+        </tr>
+        
+        <tr>
+          <td class="docs">
+            <p>You should always use <code>Join</code> instead of
+concatenating <code>/</code>s or <code>\</code>s manually. In addition
+to providing portability, <code>Join</code> will also
+normalize paths by removing superfluous separators
+and directory changes.</p>
+
+          </td>
+          <td class="code leading">
+            
+            <div class="highlight"><pre>    <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">filepath</span><span class="p">.</span><span class="nx">Join</span><span class="p">(</span><span class="s">&quot;dir1//&quot;</span><span class="p">,</span> <span class="s">&quot;filename&quot;</span><span class="p">))</span>
+    <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">filepath</span><span class="p">.</span><span class="nx">Join</span><span class="p">(</span><span class="s">&quot;dir1/../dir1&quot;</span><span class="p">,</span> <span class="s">&quot;filename&quot;</span><span class="p">))</span>
+</pre></div>
+
+          </td>
+        </tr>
+        
+        <tr>
+          <td class="docs">
+            <p><code>Dir</code> and <code>Base</code> can be used to split a path to the
+directory and the file. Alternatively, <code>Split</code> will
+return both in the same call.</p>
+
+          </td>
+          <td class="code leading">
+            
+            <div class="highlight"><pre>    <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="s">&quot;Dir(p):&quot;</span><span class="p">,</span> <span class="nx">filepath</span><span class="p">.</span><span class="nx">Dir</span><span class="p">(</span><span class="nx">p</span><span class="p">))</span>
+    <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="s">&quot;Base(p):&quot;</span><span class="p">,</span> <span class="nx">filepath</span><span class="p">.</span><span class="nx">Base</span><span class="p">(</span><span class="nx">p</span><span class="p">))</span>
+</pre></div>
+
+          </td>
+        </tr>
+        
+        <tr>
+          <td class="docs">
+            <p>To check whether a path is absolute, use <code>IsAbs</code>.</p>
+
+          </td>
+          <td class="code leading">
+            
+            <div class="highlight"><pre>    <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">filepath</span><span class="p">.</span><span class="nx">IsAbs</span><span class="p">(</span><span class="s">&quot;dir/file&quot;</span><span class="p">))</span>
+    <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">filepath</span><span class="p">.</span><span class="nx">IsAbs</span><span class="p">(</span><span class="s">&quot;/dir/file&quot;</span><span class="p">))</span>
+</pre></div>
+
+          </td>
+        </tr>
+        
+        <tr>
+          <td class="docs">
+            
+          </td>
+          <td class="code leading">
+            
+            <div class="highlight"><pre>    <span class="nx">filename</span> <span class="o">:=</span> <span class="s">&quot;config.json&quot;</span>
+</pre></div>
+
+          </td>
+        </tr>
+        
+        <tr>
+          <td class="docs">
+            <p>To find a file&rsquo;s extension, use <code>Ext</code>.</p>
+
+          </td>
+          <td class="code leading">
+            
+            <div class="highlight"><pre>    <span class="nx">ext</span> <span class="o">:=</span> <span class="nx">filepath</span><span class="p">.</span><span class="nx">Ext</span><span class="p">(</span><span class="nx">filename</span><span class="p">)</span>
+    <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">ext</span><span class="p">)</span>
+</pre></div>
+
+          </td>
+        </tr>
+        
+        <tr>
+          <td class="docs">
+            <p>To find the file&rsquo;s name with the extension removed,
+use <code>TrimSuffix</code>.</p>
+
+          </td>
+          <td class="code leading">
+            
+            <div class="highlight"><pre>    <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">strings</span><span class="p">.</span><span class="nx">TrimSuffix</span><span class="p">(</span><span class="nx">filename</span><span class="p">,</span> <span class="nx">ext</span><span class="p">))</span>
+</pre></div>
+
+          </td>
+        </tr>
+        
+        <tr>
+          <td class="docs">
+            <p><code>Rel</code> finds a relative path between a <em>base</em> and a
+<em>target</em>.</p>
+
+          </td>
+          <td class="code leading">
+            
+            <div class="highlight"><pre>    <span class="nx">rel</span><span class="p">,</span> <span class="nx">err</span> <span class="o">:=</span> <span class="nx">filepath</span><span class="p">.</span><span class="nx">Rel</span><span class="p">(</span><span class="s">&quot;a/b&quot;</span><span class="p">,</span> <span class="s">&quot;a/b/t/file&quot;</span><span class="p">)</span>
+    <span class="k">if</span> <span class="nx">err</span> <span class="o">!=</span> <span class="kc">nil</span> <span class="p">{</span>
+        <span class="nb">panic</span><span class="p">(</span><span class="nx">err</span><span class="p">)</span>
+    <span class="p">}</span>
+    <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">rel</span><span class="p">)</span>
+</pre></div>
+
+          </td>
+        </tr>
+        
+        <tr>
+          <td class="docs">
+            
+          </td>
+          <td class="code">
+            
+            <div class="highlight"><pre>    <span class="nx">rel</span><span class="p">,</span> <span class="nx">err</span> <span class="p">=</span> <span class="nx">filepath</span><span class="p">.</span><span class="nx">Rel</span><span class="p">(</span><span class="s">&quot;a/b&quot;</span><span class="p">,</span> <span class="s">&quot;a/c/t/file&quot;</span><span class="p">)</span>
+    <span class="k">if</span> <span class="nx">err</span> <span class="o">!=</span> <span class="kc">nil</span> <span class="p">{</span>
+        <span class="nb">panic</span><span class="p">(</span><span class="nx">err</span><span class="p">)</span>
+    <span class="p">}</span>
+    <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">rel</span><span class="p">)</span>
+<span class="p">}</span>
+</pre></div>
+
+          </td>
+        </tr>
+        
+      </table>
+      
+      <table>
+        
+        <tr>
+          <td class="docs">
+            
+          </td>
+          <td class="code">
+            
+            <div class="highlight"><pre><span class="gp">$</span> go run file-paths.go
+<span class="go">p: dir1/dir2/filename</span>
+<span class="go">dir1/filename</span>
+<span class="go">dir1/filename</span>
+<span class="go">Dir(p): dir1/dir2</span>
+<span class="go">Base(p): filename</span>
+<span class="go">false</span>
+<span class="go">true</span>
+<span class="go">.json</span>
+<span class="go">config</span>
+<span class="go">t/file</span>
+<span class="go">../c/t/file</span>
+</pre></div>
+
+          </td>
+        </tr>
+        
+      </table>
+      
+      
+      <p class="next">
+        Next example: <a href="command-line-arguments">Command-Line Arguments</a>.
+      </p>
+      
+      <p class="footer">
+        by <a href="https://markmcgranaghan.com">Mark McGranaghan</a> | <a href="https://github.com/mmcgrana/gobyexample/blob/master/examples/file-paths">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
+      </p>
+    </div>
+  </body>
+</html>
--- a/public/index.html
+++ b/public/index.html
@ -141,6 +141,8 @@
      
        <li><a href="line-filters">Line Filters</a></li>
      
+        <li><a href="file-paths">File Paths</a></li>
+      
        <li><a href="command-line-arguments">Command-Line Arguments</a></li>
      
        <li><a href="command-line-flags">Command-Line Flags</a></li>
--- a/public/line-filters
+++ b/public/line-filters
@ -183,7 +183,7 @@ lowercase lines.</p>
      
      
      <p class="next">
-        Next example: <a href="command-line-arguments">Command-Line Arguments</a>.
+        Next example: <a href="file-paths">File Paths</a>.
      </p>
      
      <p class="footer">