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authorCraig Jennings <c@cjennings.net>2024-04-07 13:41:34 -0500
committerCraig Jennings <c@cjennings.net>2024-04-07 13:41:34 -0500
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+<h1> Package cmp </h1> <ul id="short-nav">
+<li><code>import "cmp"</code></li>
+<li><a href="#pkg-overview" class="overviewLink">Overview</a></li>
+<li><a href="#pkg-index" class="indexLink">Index</a></li>
+<li><a href="#pkg-examples" class="examplesLink">Examples</a></li>
+</ul> <h2 id="pkg-overview">Overview </h2> <p>Package cmp provides types and functions related to comparing ordered values. </p> <h2 id="pkg-index">Index </h2> <ul id="manual-nav">
+<li><a href="#Compare">func Compare[T Ordered](x, y T) int</a></li>
+<li><a href="#Less">func Less[T Ordered](x, y T) bool</a></li>
+<li><a href="#Or">func Or[T comparable](vals ...T) T</a></li>
+<li><a href="#Ordered">type Ordered</a></li>
+</ul> <div id="pkg-examples"> <h3>Examples</h3> <dl> <dd><a class="exampleLink" href="#example_Or">Or</a></dd> <dd><a class="exampleLink" href="#example_Or_sort">Or (Sort)</a></dd> </dl> </div> <h3>Package files</h3> <p> <span>cmp.go</span> </p> <h2 id="Compare">func <span>Compare</span> </h2> <pre data-language="go">func Compare[T Ordered](x, y T) int</pre> <p>Compare returns </p>
+<pre data-language="go">-1 if x is less than y,
+ 0 if x equals y,
++1 if x is greater than y.
+</pre> <p>For floating-point types, a NaN is considered less than any non-NaN, a NaN is considered equal to a NaN, and -0.0 is equal to 0.0. </p>
+<h2 id="Less">func <span>Less</span> </h2> <pre data-language="go">func Less[T Ordered](x, y T) bool</pre> <p>Less reports whether x is less than y. For floating-point types, a NaN is considered less than any non-NaN, and -0.0 is not less than (is equal to) 0.0. </p>
+<h2 id="Or">func <span>Or</span> </h2> <pre data-language="go">func Or[T comparable](vals ...T) T</pre> <p>Or returns the first of its arguments that is not equal to the zero value. If no argument is non-zero, it returns the zero value. </p> <h4 id="example_Or"> <span class="text">Example</span>
+</h4> <p>Code:</p> <pre class="code" data-language="go">// Suppose we have some user input
+// that may or may not be an empty string
+userInput1 := ""
+userInput2 := "some text"
+
+fmt.Println(cmp.Or(userInput1, "default"))
+fmt.Println(cmp.Or(userInput2, "default"))
+fmt.Println(cmp.Or(userInput1, userInput2, "default"))
+</pre> <p>Output:</p> <pre class="output" data-language="go">default
+some text
+some text
+</pre> <h4 id="example_Or_sort"> <span class="text">Example (Sort)</span>
+</h4> <p>Code:</p> <pre class="code" data-language="go">type Order struct {
+ Product string
+ Customer string
+ Price float64
+}
+orders := []Order{
+ {"foo", "alice", 1.00},
+ {"bar", "bob", 3.00},
+ {"baz", "carol", 4.00},
+ {"foo", "alice", 2.00},
+ {"bar", "carol", 1.00},
+ {"foo", "bob", 4.00},
+}
+// Sort by customer first, product second, and last by higher price
+slices.SortFunc(orders, func(a, b Order) int {
+ return cmp.Or(
+ cmp.Compare(a.Customer, b.Customer),
+ cmp.Compare(a.Product, b.Product),
+ cmp.Compare(b.Price, a.Price),
+ )
+})
+for _, order := range orders {
+ fmt.Printf("%s %s %.2f\n", order.Product, order.Customer, order.Price)
+}
+
+</pre> <p>Output:</p> <pre class="output" data-language="go">foo alice 2.00
+foo alice 1.00
+bar bob 3.00
+foo bob 4.00
+bar carol 1.00
+baz carol 4.00
+</pre> <h2 id="Ordered">type <span>Ordered</span> <span title="Added in Go 1.21">1.21</span> </h2> <p>Ordered is a constraint that permits any ordered type: any type that supports the operators &lt; &lt;= &gt;= &gt;. If future releases of Go add new ordered types, this constraint will be modified to include them. </p>
+<p>Note that floating-point types may contain NaN ("not-a-number") values. An operator such as == or &lt; will always report false when comparing a NaN value with any other value, NaN or not. See the <a href="#Compare">Compare</a> function for a consistent way to compare NaN values. </p>
+<pre data-language="go">type Ordered interface {
+ ~int | ~int8 | ~int16 | ~int32 | ~int64 |
+ ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr |
+ ~float32 | ~float64 |
+ ~string
+}</pre><div class="_attribution">
+ <p class="_attribution-p">
+ &copy; Google, Inc.<br>Licensed under the Creative Commons Attribution License 3.0.<br>
+ <a href="http://golang.org/pkg/cmp/" class="_attribution-link">http://golang.org/pkg/cmp/</a>
+ </p>
+</div>