这向所有消费者发出信号，表明不会再有新的数据到来。
理解复杂数据结构 假设我们有一个名为$events的Laravel集合，其结构如以下dd()输出所示：Illuminate\Database\Eloquent\Collection {#948 ▼ #items: array:3 [▼ "26-01-2021" => Illuminate\Database\Eloquent\Collection {#972 ▶} "01-02-2021" => Illuminate\Database\Eloquent\Collection {#962 ▶} "03-11-2021" => Illuminate\Database\Eloquent\Collection {#965 ▼ #items: array:1 [▼ 0 => App\Models\DaysEvent {#994 ▼ #table: "days_events" // ... 其他Eloquent模型属性 #attributes: array:29 [▼ "id" => 166 "title" => "Individual Interview" "slug" => "individual-interview" "location" => "Online" // ... 其他属性 ] // ... } ] } ] }从上述结构可以看出： $events本身是一个Illuminate\Database\Eloquent\Collection实例。
完整代码示例<!DOCTYPE html> <html> <head> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <style> * { box-sizing: border-box; } body { background-color: #f1f1f1; } #regForm { background-color: #ffffff; margin: 10px auto; font-family: Raleway; padding: 10px; width: 90%; min-width: 300px; } h1 { text-align: center; } input { padding: 10px; width: 100%; font-size: 17px; font-family: Raleway; border: 1px solid #aaaaaa; } /* Mark input boxes that gets an error on validation: */ input.invalid { background-color: #ffdddd; } /* Hide all steps by default: */ .tab { display: none; } button { background-color: #04AA6D; color: #ffffff; border: none; padding: 10px 20px; font-size: 17px; font-family: Raleway; cursor: pointer; } button:hover { opacity: 0.8; } #prevBtn { background-color: #bbbbbb; } /* Make circles that indicate the steps of the form: */ .step { height: 15px; width: 15px; margin: 0 2px; background-color: #bbbbbb; border: none; border-radius: 50%; display: inline-block; opacity: 0.5; } .step.active { opacity: 1; } /* Mark the steps that are finished and valid: */ .step.finish { background-color: #04AA6D; } .autocomplete { position: relative; display: inline-block; } .autocomplete-items { position: absolute; border: 1px solid #d4d4d4; border-bottom: none; border-top: none; z-index: 99; /*position the autocomplete items to be the same width as the container:*/ top: 100%; left: 0; right: 0; } .autocomplete-items div { padding: 10px; cursor: pointer; background-color: #fff; border-bottom: 1px solid #d4d4d4; } .autocomplete-items div:hover { /*when hovering an item:*/ background-color: #e9e9e9; } .autocomplete-active { /*when navigating through the items using the arrow keys:*/ background-color: DodgerBlue !important; color: #ffffff; } </style> <body> <form id="regForm" action="/submit_page.php"> <h1>Your Nutrition Needs:</h1> <div class="tab">Your Fruit: <p class="autocomplete"> <input id="myFruitList" type="text" name="fruit" placeholder="Start typing your fruit name"></p> </div> </form> <script> function fruitautocomplete(inp, arr) { /*the autocomplete function takes two arguments, the text field element and an array of possible autocompleted values:*/ var currentFocus; /*execute a function when someone writes in the text field:*/ inp.addEventListener("input", function(e) { var a, b, i, val = this.value; /*close any already open lists of autocompleted values*/ closeAllLists(); if (!val) { return false; } currentFocus = -1; /*create a DIV element that will contain the items (values):*/ a = document.createElement("DIV"); a.setAttribute("id", this.id + "autocomplete-list"); a.setAttribute("class", "autocomplete-items"); /*append the DIV element as a child of the autocomplete container:*/ this.parentNode.appendChild(a); /*for each item in the array...*/ for (i = 0; i < arr.length; i++) { /*check if the item starts with the same letters as the text field value:*/ if (arr[i].toUpperCase().indexOf(val.toUpperCase()) > -1) { /*create a DIV element for each matching element:*/ b = document.createElement("DIV"); /*make the matching letters bold:*/ let index = arr[i].toUpperCase().indexOf(val.toUpperCase()); b.innerHTML = arr[i].substr(0, index); b.innerHTML += "<strong>" + arr[i].substr(index, val.length) + "</strong>"; b.innerHTML += arr[i].substr(index + val.length); /*insert a input field that will hold the current array item's value:*/ b.innerHTML += "<input type='hidden' value='" + arr[i] + "'>"; /*execute a function when someone clicks on the item value (DIV element):*/ b.addEventListener("click", function(e) { /*insert the value for the autocomplete text field:*/ inp.value = this.getElementsByTagName("input")[0].value; /*close the list of autocompleted values, (or any other open lists of autocompleted values:*/ closeAllLists(); }); a.appendChild(b); } } }); /*execute a function presses a key on the keyboard:*/ inp.addEventListener("keydown", function(e) { var x = document.getElementById(this.id + "autocomplete-list"); if (x) x = x.getElementsByTagName("div"); if (e.keyCode == 40) { /*If the arrow DOWN key is pressed, increase the currentFocus variable:*/ currentFocus++; /*and and make the current item more visible:*/ addActive(x); } else if (e.keyCode == 38) { //up /*If the arrow UP key is pressed, decrease the currentFocus variable:*/ currentFocus--; /*and and make the current item more visible:*/ addActive(x); } else if (e.keyCode == 13) { /*If the ENTER key is pressed, prevent the form from being submitted,*/ e.preventDefault(); if (currentFocus > -1) { /*and simulate a click on the "active" item:*/ if (x) x[currentFocus].click(); } } }); inp.addEventListener("focus", function(e) { if (!this.value) { showAllOptions(this, fruitlist); } }); inp.addEventListener("blur", function(e) { let valid = false; for (let i = 0; i < fruitlist.length; i++) { if (fruitlist[i] === this.value) { valid = true; break; } } if (!valid) { this.value = ""; // Clear the input if it's invalid alert("Please select a valid fruit from the list."); } }); function addActive(x) { /*a function to classify an item as "active":*/ if (!x) return false; /*start by removing the "active" class on all items:*/ removeActive(x); if (currentFocus >= x.length) currentFocus = 0; if (currentFocus < 0) currentFocus = (x.length - 1); /*add class "autocomplete-active":*/ x[currentFocus].classList.add("autocomplete-active"); } function removeActive(x) { /*a function to remove the "active" class from all autocomplete items:*/ for (var i = 0; i < x.length; i++) { x[i].classList.remove("autocomplete-active"); } } function closeAllLists(elmnt) { /*close all autocomplete lists in the document, except the one passed as an argument:*/ var x = document.getElementsByClassName("autocomplete-items"); for (var i = 0; i < x.length; i++) { if (elmnt != x[i] && elmnt != inp) { x[i].parentNode.removeChild(x[i]); } } } function showAllOptions(inp, arr) { var a, b, i, val = ""; // val设为空，显示所有项 closeAllLists(); currentFocus = -1; a = document.createElement("DIV"); a.setAttribute("id", inp.id + "autocomplete-list"); a.setAttribute("class", "autocomplete-items"); inp.parentNode.appendChild(a); for (i = 0; i < arr.length; i++) { b = document.createElement("DIV"); b.innerHTML = arr[i]; b.innerHTML += "<input type='hidden' value='" + arr[i] + "'>"; b.addEventListener("click", function(e) { inp.value = this.getElementsByTagName("input")[0].value; closeAllLists(); }); a.appendChild(b); } } /*execute a function when someone clicks in the document:*/ document.addEventListener("click", function(e) { closeAllLists(e.target); }); } /*An array containing all the country names in the world:*/ var fruitlist = [ "Apple", "Mango", "Pear", "Banana", "Berry" ]; /*initiate the autocomplete function on the "myFruitList" element, and pass along the fruit array as possible autocomplete values:*/ fruitautocomplete(document.getElementById("myFruitList"), fruitlist); </script> </body> </html>注意事项 性能: 对于大型数据集，模糊匹配可能会影响性能。
PHP 实时输出运行日志，关键在于关闭输出缓冲、强制刷新输出内容，并确保响应流不被中间层（如 Web 服务器或代理）缓存。
通过确保MySQL数据库、表和PDO连接的字符集设置保持一致，并优先考虑使用 utf8mb4 字符集，您可以有效地避免乱码问题，确保多语言数据能够准确无误地存储和显示。
class Parent: @classmethod def func1(cls): print("hello func1") @classmethod def func2(cls): print("hello func2") @classmethod def func3(cls): print("hello func3") CALCULATE = [func1, func2, func3] NO_CALCULATE_FUNCS = [] # 存储底层函数对象 @classmethod def calculate_kpis(cls): for func in cls.CALCULATE: # 比较底层函数对象 if func.__func__ not in cls.NO_CALCULATE_FUNCS: func(cls) # 直接调用绑定方法 class Child(Parent): # 移除这个计算，通过存储Parent.func1的底层函数 NO_CALCULATE_FUNCS = [Parent.func1.__func__] if __name__ == "__main__": p1 = Child() p1.calculate_kpis()这种方法虽然可行，但需要确保NO_CALCULATE列表中的元素也是底层函数对象，这可能会增加代码的复杂性。
std::pair是C++中用于组合两个值的模板类，支持构造函数、make_pair和花括号初始化，通过first和second访问元素，常用于返回多值函数和map容器。
// os.Exit(0)确保程序立即退出，防止其他Goroutine继续执行或打印。
Golang凭借其高并发和低延迟的特性，广泛应用于微服务开发。
dynamic_cast在运行时进行安全的向下转型，依赖RTTI检查类型，转换失败返回nullptr或抛异常，要求类有多态性；static_cast在编译期完成转换，无运行时开销，适用于已知安全的场景如向上转型或基本类型转换，但向下转型时不检查类型，错误使用导致未定义行为。
在Python包安装过程中，当pip尝试构建wheel时，可能会遇到subprocess-exited-with-error错误，导致安装失败。
在Golang中实现goroutine并发执行非常直接，Go语言通过轻量级线程（goroutine）和通道（channel）提供了强大的并发支持。
尽管Go语言规范在for语句的range迭代部分提到，如果在迭代过程中有新的条目被插入或未达到的条目被删除，range迭代器会以某种方式处理这些变化而不会导致程序崩溃。
要避免这个问题，关键在于避免按值传递多态类型，并合理使用指针或引用。
但实际上，PHP有很多细节需要注意。
可用 os.Remove 和 filepath.Glob 实现： files, _ := filepath.Glob("logs/*.log.*") for _, f := range files { info, err := os.Stat(f) if err != nil { continue } if time.Since(info.ModTime()).Hours() > 24*30 { // 超过30天 os.Remove(f) } } 建议将此逻辑放在程序启动时或通过定时任务执行。
值类型传递复制数据副本，函数内修改不影响原变量；引用类型传递内存地址，修改直接影响原对象，二者在内存操作、影响范围和性能上存在差异。
传统优化方法的局限性 考虑一个典型的场景：我们有一个 8x8 的矩阵 A 和 8x1 的向量 b，需要求解 X。
当自定义类型zMsg定义为[]zFrame而zFrame定义为[]byte时，Go编译器不允许直接将[][]byte类型变量强制转换为zMsg。
标准库并未直接提供这样的功能，因此需要我们自定义实现。
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