这可能是超级基本的，但我已经尝试了很多未能触及的东西..
我想将一个数字更改为它的否定版本。
answer = []
array = [3, 5, 2, 19, 2, 1]
array.each.with_index do |x, i|
if x > array[i+1]
answer << array[i] * -1
else x =< array[i+1]
answer << array[i]
end
end
=> the answer I want is [-5] for when 'true' but I'm getting [5]
我也试过制作一个新的＆＃39; negarray＆＃39;将所有等效的负数作为＆＃39; array＆＃39;
answer = []
array = [3, 5, 2, 19, 2, 1]
negarray = [-3, -5, -2, -19, -2, -1]
=> again, getting [5], and not the [-5] I want.
干杯！
答案 0 :(得分：4)
在实际版本中，问题不明确。
如果你的意思是
我想将一个数字更改为它的否定版本。
你想要一个负数，然后你可以尝试：
answer = []
array = [3, 5, 6, 19, 2, 1]
array.each do |x|
if x > 0
answer << x * -1
else
answer << x
end
end
p answer
或
array.each do |x|
answer << if x > 0
x * -1
else
x
end
end
或使用三元运算符：
array.each do |x|
answer << (x > 0 ? -x : x)
end
或更短且更红宝石的esk（使用三元运算符）：
array = [3, 5, 6, 19, 2, -1]
answer = array.map { |n| n > 0 ? -n : n }
如果你喜欢更长的时间：
answer = array.map do |n|
if n > 0
-n
else
n
end
end
如果您不想使用任何if结构，那么您可以使用负abs方法：
answer = array.map { |n| -n.abs }
答案 1 :(得分：4)
以下一行
if x > array[i+1]
您基本上是在说明位置i处的元素是否大于i+1处的位置，您希望将其设为负数。问题是5小于下一个元素6，因此不会被否定。
让我们修复您的代码，并使用map方法来简化它：
out = array.map.with_index do |x, i|
(array[i+1].nil? || x > array[i+1]) ? x : x*-1
end
# [-3, -5, -6, 19, 2, 1]
答案 2 :(得分：-1)
如果要在索引1处获取第二个数组元素的负值，请执行以下操作
<html>
<head>
<!-----------
EVENT PAGE by clumhood
:> ------------>
<title>FANFIC RECS</title>
<link rel="shortcut icon" href="{Favicon}">
<link rel="alternate" type="application/rss+xml" href="{RSS}">
<link rel="apple-touch-icon" href="{PortraitURL-128}"/>
<link href='http://fonts.googleapis.com/css?family=Roboto:700,400' rel='stylesheet' type='text/css'>
<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/font-awesome/4.3.0/css/font-awesome.min.css">
<script type="text/javascript">
WebFontConfig = {
google: { families: [ 'Roboto:700,400:latin' ] }
};
(function() {
var wf = document.createElement('script');
wf.src = ('https:' == document.location.protocol ? 'https' : 'http') +
'://ajax.googleapis.com/ajax/libs/webfont/1/webfont.js';
wf.type = 'text/javascript';
wf.async = 'true';
var s = document.getElementsByTagName('script')[0];
s.parentNode.insertBefore(wf, s);
})(); </script>
<!------- filter scripts -------->
<script src="http://static.tumblr.com/fuu6t9w/kh8ml0pl9/jquery-1.7.1.min.js"></script>
<script src="http://static.tumblr.com/fuu6t9w/eubml0pm0/jquery.isotope.min.js"></script>
<script>
$(function(){
<!------- filter scripts -------->
<script src="http://static.tumblr.com/fuu6t9w/kh8ml0pl9/jquery-1.7.1.min.js"></script>
<script src="http://static.tumblr.com/fuu6t9w/eubml0pm0/jquery.isotope.min.js"></script>
<script>
$(function(){
var $container = $('#container');
$container.isotope({
itemSelector : '.story'
});
var $optionSets = $('#sort .option-set'),
$optionLinks = $optionSets.find('a');
$optionLinks.click(function(){
var $this = $(this);
// don't proceed if already selected
if ( $this.hasClass('selected') ) {
return false;
}
var $optionSet = $this.parents('.option-set');
$optionSet.find('.selected').removeClass('selected');
$this.addClass('selected');
// make option object dynamically, i.e. { filter: '.my-filter-class' }
var options = {},
key = $optionSet.attr('data-option-key'),
value = $this.attr('data-option-filter');
// parse 'false' as false boolean
value = value === 'false' ? false : value;
options[ key ] = value;
if ( key === 'layoutMode' && typeof changeLayoutMode === 'function' ) {
// changes in layout modes need extra logic
changeLayoutMode( $this, options )
} else {
// otherwise, apply new options
$container.isotope( options );
}
return false;
});
});
</script>
<!-----end filter scripts------>
<!-----end filter scripts------>
<style type="text/css">
body {
font-family:arial;
font-size:12px;
background:#f8f8f8; /**this is the color of the bg.*/
}
a {
color:#008997; /**this is the color of the links.*/
text-decoration:none;
}
::-webkit-scrollbar {
background-color: white;
height:8px;
width:5px
}
::-webkit-scrollbar-thumb:vertical {
background-color:#f8f8f8;
height:50px
}
::-webkit-scrollbar-thumb:horizontal {
background-color:#505050;
height:8px!important
}
.top {
text-align:left;
padding-bottom:0px;
margin-bottom:10px;
margin-top:-9px;
margin-left:-7px;
}
.top2 {
width:1080px;
background:white; /**this is the color of the filter titles topbar background.*/
text-align:left;
padding-bottom:0px;
margin-bottom:10px;
margin-top:10px;
margin-left:-7px;
line-height:20px;
}
#sort {
padding:10px;
text-align:center;
font-family:'roboto', sans-serif;
font-size:10px;
text-transform:uppercase;
}
#sort a {
margin-left:20px;
}
#sort a:hover {
color:#bb2576; /**this is the color of the filter links when you hover over them.*/
}
.title {
float:left;
padding:15px;
padding-top:20px;
font-family:'roboto', sans-serif;
font-size:12px;
color:#bb2576;
font-weight:normal;
}
.links {
width:1100px;
text-align:center;
padding:30px;
}
.links a {
font-family:'roboto', sans-serif;
font-size:11px;
text-transform:uppercase;
padding:30px;
margin-left:-3px;
}
.links a:hover {
color:#b60079; /**this is the color of the links when you hover over them.*/
}
.links a:last-child {
}
#container {
width:1080px;
margin-top:10px;
}
#content {
margin:10px;
overflow:hidden;
width:250px;
height:250px;
float:center;
box-shadow:0px 3px 10px rgba(0,0,0,.15);
text-align:left;
line-height:150%;
background:white; /**this is the color of the background of each event.*/
transition-duration:1s;
-moz-transition-duration:1s;
-webkit-transition-duration:1s;
-o-transition-duration:1s;
}
.desc {
padding:10px;
margin-top:10px;
font-size:11px;
}
#content2 {
margin:10px;
overflow:hidden;
width:250px;
height:250px;
float:left;
box-shadow:0px 3px 10px rgba(0,0,0,.15);
text-align:left;
line-height:150%;
background:#ffffff; /**this is the color of the background of each past event.*/
transition-duration:1s;
-moz-transition-duration:1s;
-webkit-transition-duration:1s;
-o-transition-duration:1s;
}
</style>
</head>
<body>
要将数组的所有值更改为负数，请使用以下
answer << array[1] * -1