在d3中約束軸標籤

Question

我正在學習一個教程，以便學習一些d3js。

這裏是我的代碼：

'use strict'; 
//Dashboard 

//setup size of line chart 
var margin = {top: 20, right: 20, bottom: 30, left: 50}, 
width = 600 - margin.left - margin.right, 
height = 400 - margin.top - margin.bottom; 

//parse data from file 
var parseDate = d3.time.format("%b").parse; 

//set scales 
var x = d3.time.scale() 
    .range([0, width]); 

var y = d3.scale.linear() 
    .range([height, 0]); 

//create axes 
var xAxis = d3.svg.axis() 
    .scale(x) 
    .orient("bottom"); 

var yAxis = d3.svg.axis() 
    .scale(y) 
    .orient("left"); 

//construct the line using points from data 
var line = d3.svg.line() 
    .x(function(d) { return x(d.date); }) 
    .y(function(d) { return y(d.users); }); 

var svg = d3.select(".linechart").append("svg") 
    .attr("width", width + margin.left + margin.right) 
    .attr("height", height + margin.top + margin.bottom) 
    .append("g") 
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")"); 

d3.tsv("data.tsv", function(error, data) { 
    if (error) throw error; 
//traverse through the data 
    data.forEach(function(d) { 
    d.date = parseDate(d.date); 
    d.users = +d.users; 
    }); 
//establish the domain for x and y axes 
    x.domain(d3.extent(data, function(d) { return d.date; })); 
    y.domain(d3.extent(data, function(d) { return d.users; })); 

//add "groups" 
    svg.append("g") 
     .attr("class", "x axis") 
     .attr("transform", "translate(0," + height + ")") 
     .call(xAxis); 

    svg.append("g") 
     .attr("class", "y axis") 
     .call(yAxis) 
    .append("text") 
     .attr("transform", "rotate(-90)") 
     .attr("y", 6) 
     .attr("dy", ".71em") 
     .style("text-anchor", "end") 
     .text("Users (unique)"); 

    svg.append("path") 
     .datum(data) 
     .attr("class", "line") 
     .attr("d", line); 
}); 

結果是這樣的：

的數據是：

date users 
Jan 10 
Feb 20 
Mar 30 
.... 

我的問題是關於軸，怎麼我可以強制它不在x軸上插入不在數據集中的標籤嗎？

Answer 1

集蜱用於手動x軸：

... 
if (error) throw error; 

var ticks = data.map(function(d) { return parseDate(d.date) }; 
... 
x.domain(d3.extent(data, function(d) { return d.date; })).tickValues(ticks); 

https://github.com/d3/d3-3.x-api-reference/blob/master/SVG-Axes.md#tickValues