To get the last item from an array in React.js, you can use multiple approaches. One way is to utilize the length property of the array. By subtracting 1 from the length, you can access the last item using array[length - 1]
g.IsType(columnIndex, 'Number'))64thrownewTypeError('参数 columnIndex 必须是一个数字');6566if(columnIndex <= 0 || columnIndex > 16384)67thrownewError('Please make sure 1 <= columnIndex <= 16384.');6869let address =ActiveSheet.Columns.Item(columnIndex).Address(...
log(item, index) }) push:添加元素到数组的末尾 代码语言:javascript 代码运行次数:0 运行 AI代码解释 let newLength = array.push('Orange') pop:删除数组末尾的元素 代码语言:javascript 代码运行次数:0 运行 AI代码解释 let last = array.pop() shift:删除数组头部元素 代码语言:javascript 代码运行次数:0...
lastIndexOf() 方法可返回一个指定的元素在数组中最后出现的位置,从该字符串的后面向前查找。如果要检索的元素没有出现,则该方法返回 -1。该方法将从尾到头地检索数组中指定元素 item。开始检索的位置在数组的 start 处或数组的结尾(没有指定 start 参数时)。如果找到一个 item,则返回 item 从尾向前检索第一...
(0,ObjHid.value.lastIndexOf(",")); 112 alert(ObjHid.value); 113 } 114 115 116 117 118 119 120 121 <TR> 122 <TD style="WIDTH: 79px; height: 123px;"> 123 <asp:ListBox ID="lbMoveFrom" runat="server" Height="120px" SelectionMode="Multiple" 124 Width="82px"> 125 <as...
isArrayLink(arr)){ //不是类数组对象 return arr } let result = [] let objarr = [] let obj = Object.create(null) arr.forEach(item => { if(isStatic(item)){ //是除了symbol外的原始数据 let key = item + '_' + getRawType(item); if(!obj[key]){ obj[key] = true result.push...
array.flat(n)是es10嵌入层叠的api,n表示尺寸,n变化infinity时维度为无限大 2.开始篇 function flatten ( arr ) { while (arr.some( item => array .isarray(item))) { arr = [].concat(...arr); } return arr; } flatten([ 1 ,[ 2 , 3 ]]...
arrayCopy.push(toAppend.last); } return arrayCopy; } append([2, 3, 4], { first: 1, last: 5 }); // => [1, 2, 3, 4, 5] append([10], { first: 0, last: false }); // => [0, 10, false] 'first' in toAppend(和'last' in toAppend)在对应属性存在时为true,否则为fal...
A Blob represents the contents of a file in memory.A file handle is anything that can identify a file. You get to own this concept, and define how to identify files. It could be anything from an index into an array, to a Dropbox file ID, to an IPFS URL, to a file path. It ...
/*** 获取视频第一帧当作封面* @param {object|string} file 文件对象|视频链接* @returns*/exportfunctionextractVideoCover(file){returnnewPromise((resolve)=>{constvideo=document.createElement('video')constcanvas=document.createElement('canvas')constcontext=canvas.getContext('2d')video.preload='metadata'...