给定2000个<html>
<head>
<title>Image carousel</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" type="text/css" href="reset.css">
<link rel="stylesheet" type="text/css" href="carouselcss.css">
<!-- <link href="https://fonts.googleapis.com/css?family=Baloo+Tamma" rel="stylesheet"> -->
</head>
<body>
<header>
header is here
</header>
<div id="carousel">
<div class="sliderbuttons">
<input type="button" name="next" id="next" value=">">
<input type="button" name="prev" id="prev" value="<">
</div>
<div class="slides">
<img src="http://www.planwallpaper.com/static/images/4-Nature-Wallpapers-2014-1_ukaavUI.jpg" alt="image1" class="slide active">
<img src="http://www.mrwallpaper.com/wallpapers/green-Rice-1600x900.jpg" alt="image2" class="slide">
<img src="http://cdn.wonderfulengineering.com/wp-content/uploads/2016/01/nature-wallpapers-10.jpg" alt="image3" class="slide">
</div>
<div class="indicators">
<div class="circle blip"></div>
<div class="circle"></div>
<div class="circle"></div>
</div>
</div>
</div>
</body>
</html>
html,body {
height: 100%;
position: relative;
background-color: #ccc;
}
*{
box-sizing: border-box;
}
#container {
width: 90%;
margin: 0 auto;
height: 100%;
background-color: white;
}
header {
background: black;
height: 20px;
padding: 1.5em;
color: white;
}
#carousel {
position: relative;
margin: 0 auto;
width: 45%;
margin-top: 15px;
height: 100%;
background-color: pink
}
.slide {
position: absolute;
width: 100%;
z-index: 0;
height: 100%;
}
.sliderbuttons {
}
#prev,#next {
position: absolute;
background-color: rgba(255, 148, 41, 0.68);
box-shadow: 2px white;
border:none;
font-size: 2em;
padding: 1%;
color: white;
font-weight: bold;
font-family: 'Baloo Tamma', cursive;
height: 100%;
width: 10%;
/*making the prev,next on top of content*/
z-index: 2;
}
#prev {
left:0;
}
#next {
right:0;
}
.active {
z-index: 1;
}
.indicators {
z-index: 2;
position: absolute;
bottom:49%;
left: 45%;
}
.circle {
border-radius: 10px;
width: 10px;
height: 5px;
border:2px solid black;
}
.indicators div {
padding: 8px;
margin: 2px;
display: inline-block;
}
.blip {
background-color: orange;
}
div.indicators:hover {
cursor: pointer;
}
个对象，每个对象的Story属性等于大约500个字符的字符串。
比较它们的最快方法是什么？
body OR
@stories.uniq { |story| story.body }转换为body表示形式，然后运行Fixnum？我有一种模糊的感觉，即计算机能够比字符更快地比较数字，但我也知道每个字符实际上只是用字节表示。
答案 0 :(得分：4)
很容易对这些事情进行基准测试。例如：
require 'benchmark'
string_array = 1.upto(2000).inject([]) do |arr|
arr << 1.upto(500).inject("") { |str| str << rand(10).to_s }
end
fixnum_array = string_array.map(&:to_i)
Benchmark.bm do |x|
x.report("bignum:") { 1000.times { fixnum_array.uniq } }
x.report("bignum_and_to_i:") { 1000.times { string_array.map(&:to_i).uniq } }
x.report("string:") { 1000.times { string_array.uniq } }
end
输出：
user system total real
bignum: 1.710000 0.010000 1.720000 ( 1.729463)
bignum_and_to_i: 28.500000 0.160000 28.660000 ( 28.738891)
string: 1.740000 0.000000 1.740000 ( 1.754165)
比较包含大约500位数字的2000个字符串比首先将字符串转换为数字然后进行比较要快得多。
比较长字符串与比较大字符串不会产生很大的不同。
结论：将长字符串转换为大字符串是如此之慢，以至于只比较字符串会更快。