Javascript 迭代除最后一个记号外的所有记号

我根据记号画了一堆矩形。然而，我不想为最后一个记号画一个矩形。我该怎么做？我已经尝试过切片

hoursg.selectAll（'g.tick'）

，但没有成功

编辑：更新代码并添加SVG，请参见注释

    // draw axis below data
    hoursg = svg.append('g').classed('axis', true).classed('hours', true).classed('labeled', true).attr("transform", "translate(0.5," + yaxisHeight + ")").call(hoursAxis).style("opacity", axisOpacity);

    // Need the pixel dimensions between each tick e.g. three hours.
    hoursTickSpacing = weekscale(moment(start).add(3, 'hours').toDate()) - weekscale(start.toDate());

    // add day/night shading by adding elements to the dom for every tickmark in the hours axis.
    var hourTicks = hoursg.selectAll('g.tick');

    hourTicks.filter(':not(:last-child)').insert('rect', ':first-child').attr('class', function (d, i) {
            var hours;
            hours = d.getHours();
            if (hours < 6 || hours >= 18) {
                return 'nighttime';
            } else {
                return 'daytime';
            }
        }).attr('x', 0).attr('width', hoursTickSpacing).attr('height', 8);

//在数据下方绘制轴
hoursg=svg.append（'g'）.classed（'axis'，true）。classed（'hours'，true）。classed（'labeled'，true）。attr（“transform”，“translate（0.5，+yaxisHeight+））。call（hoursAxis）。style（“opacity”，axisOpacity）；
//需要每个刻度之间的像素尺寸，例如三小时。
hoursTickSpacing=weekscale（矩（开始）.add（3，'hours'）.toDate（））-weekscale（开始.toDate（））；
//通过为小时轴中的每个记号向dom添加元素，添加日间/夜间着色。
var hourTicks=hoursg.selectAll（'g.tick'）；
hourTicks.filter（'：not（：last child））.insert（'rect'，'：first child'）.attr（'class'，function（d，i）{
var小时数；
小时=d.getHours（）；
如果（小时数<6 | |小时数>=18）{
返回“夜间”；
}否则{
返回“白天”；
}
}).attr（'x'，0.）.attr（'width'，hourstickspating.）.attr（'height'，8）；

下面是创建的SVG对象：

<g class="axis hours labeled" transform="translate(0.5,100)" style="opacity: 0.6;"><g class="tick" transform="translate(0,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(12.5,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(25,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(37.5,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(50,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(62.5,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(75,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(87.5,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(100,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(112.50000000000001,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(125,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(137.5,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(150,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(162.5,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(175,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(187.5,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(200,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(212.49999999999997,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(225.00000000000003,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(237.5,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(250,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(262.5,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(275,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(287.5,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(300,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(312.5,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(325,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(337.5,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(350,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(362.50000000000006,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(375,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(387.5,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(400,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(412.5,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(424.99999999999994,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(437.5,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(450.00000000000006,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(462.5,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(475,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(487.5,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(500,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(512.5,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(525,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(537.5,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(550,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(562.5,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(575,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(587.5,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(600,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(612.5,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(625,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(637.5,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(650,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(662.5,0)" style="opacity: 1;"><rect class="daytime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(675,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(687.5,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><g class="tick" transform="translate(700,0)" style="opacity: 1;"><rect class="nighttime" x="0" width="12.5" height="8"></rect><line y2="8" x2="0"></line><text dy=".71em" y="14" x="0" style="text-anchor: middle;"></text></g><path class="domain" d="M0,8V0H700V8"></path></g>

有问题的是

对象。

您可以使用：

其中，

isNotLastTick

是一个函数，如果给定的数据不代表最后一个刻度，则返回真实值

下面是一个

过滤器的示例：


var数据=[1,2,3,4]；
var p=d3
.selectAll（“.p”）
.数据（数据）；
p、 输入（）
.append（'p'）
.attr（'class'，'p'）
.text（函数（d）{return d}）
p、 过滤器（函数（d，i）{返回i==0}）
.attr（'style'，'color:red'）
好的，我想我理解你的方法。为此，我需要找到
hoursg的长度。选择all（'g.tick'）
，这样我的过滤器就可以是
I！=勾选长度
或类似的东西，对吗？如何计算长度？是否使用数据联接？在这种情况下，它是数据数组的长度。如果只是选择现有元素，我认为可以使用字符串
“：last child”
作为
过滤器的参数，而不是函数。我以前没有试过。我对d3还是很陌生，所以我不太确定。但是我不认为我在使用数据连接，因为我没有在脚本中的任何地方使用
join（）
方法。感谢您的更新。这将选择最后一个子对象-如果我要选择除最后一个子对象以外的所有其他对象，该怎么办？只需使用不同的CSS选择器即可-
：not（：last child）
。我已经更新了示例。
hoursg.selectAll('g.tick')
  .filter(isNotLastTick)
  .insert('rect')
  //...