javascript - 更新 y 轴标题

Question

对于下面的 d3 图表，我需要更新 y 轴标题。目前它是温度，°F，但我想在第二次调用中将其设置为温度，°C。

<script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
      .axis--x path {
          display: none;
      }

      .line {
          fill: none;
          stroke: steelblue;
          stroke-width: 1.5px;
      }

  </style>
  <button>Click me</button>
  <svg width="960" height="500"></svg>
  <!--<script src="d3.v4.js"></script>-->

  <script>
      var svg = d3.select("svg"),
          margin = {
              top: 20,
              right: 80,
              bottom: 30,
              left: 50
          },
          width = svg.attr("width") - margin.left - margin.right,
          height = svg.attr("height") - margin.top - margin.bottom,
          g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");

      var parseTime = d3.timeParse("%Y%m%d");

      var x = d3.scaleTime().range([0, width]),
          y = d3.scaleLinear().range([height, 0]),
          z = d3.scaleOrdinal(d3.schemeCategory10);

      var line = d3.line()
          .curve(d3.curveBasis)
          .x(function (d) {
              return x(d.date);
          })
          .y(function (d) {
              return y(d.temperature);
          });

      var data = [{
          "date": "1116156400000",
          "Old York": 63.4,
          "San Francisco": 62.7,
          "Austin": 72.2
      }, {
          "date": "1167692400000",
          "Old York": 58.0,
          "San Francisco": 59.9,
          "Austin": 67.7
      }, {
          "date": "1199228400000",
          "Old York": 53.3,
          "San Francisco": 59.1,
          "Austin": 69.4
      }, {
          "date": "1230850800000",
          "Old York": 55.7,
          "San Francisco": 58.8,
          "Austin": 68.0
      }, {
          "date": "1262386800000",
          "Old York": 62.3,
          "San Francisco": 55.1,
          "Austin": 71.9
      }];

      var data2 = [{
          "date": "1136156400000",
          "New York": 263.4,
          "San Francisco": 262.7,
          "Austin": 372.2
      }, {
          "date": "1167692400000",
          "New York": 458.0,
          "San Francisco": 259.9,
          "Austin": -367.7
      }, {
          "date": "1199228400000",
          "New York": 153.3,
          "San Francisco": 259.1,
          "Austin": 369.4
      }, {
          "date": "1230850800000",
          "New York": 155.7,
          "San Francisco": 258.8,
          "Austin": 368.0
      }, {
          "date": "1262386800000",
          "New York": 162.3,
          "San Francisco": 255.1,
          "Austin": 371.9
      }];


      // d3.tsv("data.tsv", type, function (error, data) {
      //     if (error) throw error;

      data.columns = ["date", "Old York", "San Francisco", "Austin"];

      var cities = data.columns.slice(1).map(function (id) {
          return {
              id: id,
              values: data.map(function (d) {
                  return {
                      date: d.date,
                      temperature: d[id]
                  };
              })
          };
      });

      x.domain(d3.extent(data, function (d) {
          return d.date;
      }));

      y.domain([
          d3.min(cities, function (c) {
              return d3.min(c.values, function (d) {
                  return d.temperature;
              });
          }),
          d3.max(cities, function (c) {
              return d3.max(c.values, function (d) {
                  return d.temperature;
              });
          })
      ]);
      g.append("g")
          .attr("class", "axis axis--x")
          .attr("transform", "translate(0," + height + ")")
          .call(d3.axisBottom(x));
      g.append("g")
          .attr("class", "axis axis--y")
          .call(d3.axisLeft(y))
          .append("text")
          .attr("transform", "rotate(-90)")
          .attr("y", 6)
          .attr("dy", "0.71em")
          .attr("fill", "#000")
          .text("Temperature, ºF");

      update();
      d3.select("button").on("click", function () {
          // cities.splice(0, 1);
          data = data2;
          data.columns = ["date", "New York", "San Francisco", "Austin"];
          //            console.log(JSON.stringify(cities));
          update();
      });

      function update() {
  //        data.columns = ["date", "New York", "San Francisco", "Austin"];
          cities = data.columns.slice(1).map(function (id) {
              return {
                  id: id,
                  values: data.map(function (d) {
                      return {
                          date: d.date,
                          temperature: d[id]
                      };
                  })
              };
          });


          x.domain(d3.extent(data, function (d) {
              return d.date;
          }));
          y.domain([
              d3.min(cities, function (c) {
                  return d3.min(c.values, function (d) {
                      return d.temperature;
                  });
              }),
              d3.max(cities, function (c) {
                  return d3.max(c.values, function (d) {
                      return d.temperature;
                  });
              })
          ]);
          z.domain(cities.map(function (c) {
              return c.id;
          }));

          var city = g.selectAll(".city")
              .data(cities);

          // var text = g.selectAll(".text")
          //     .data(texts);

          city.exit().remove();

          var cityEnter = city.enter().append("g")
              .attr("class", "city");

          cityEnter.append("path")
              .attr("class", "line")
              .attr("d", function (d) {
                  return line(d.values);
              })
              .style("stroke", function (d) {
                  return z(d.id);
              });


          city = cityEnter.merge(city);

          cityEnter.append("text")
          //        city.append("text")
              .datum(function (d) {
                  return {
                      id: d.id,
                      value: d.values[d.values.length - 1]
                  };
              })
              .attr("transform", function (d) {
                  return "translate(" + x(d.value.date) + "," + y(d.value.temperature) + ")";
              })
              .attr("x", 3)
              .attr("dy", "0.35em")
              .style("font", "10px sans-serif")
              .text(function (d) {
                  return d.id;
              });


          city.select("path")
          //            .transition().duration(1000)
              .attr("d", function (d) {
                  return line(d.values);
              });

          city.select("text").datum(function (d) {
              return {
                  id: d.id,
                  value: d.values[d.values.length - 1]
              };
          })
          .text(function (d) {
              return d.id;
          })
          //            .transition().duration(1000)
              .attr("transform", function (d) {
                  return "translate(" + x(d.value.date) + "," + y(d.value.temperature) + ")";
              });

          svg.select(".axis--y")
                      .transition().duration(1000)
              .call(d3.axisLeft(y));
              
                        svg.select(".axis--x")
                      .transition().duration(1000)
              .call(d3.axisBottom(x));
      }

  </script>

Answer 1

使用变量来定义该文本元素:

var yAxisText = gY.append("text")
    .attr("transform", "rotate(-90)")
    .attr("y", 6)
    .attr("dy", "0.71em")
    .attr("fill", "#000");

然后，使用另一个变量来设置单位:

var temp = "F";

在update函数中，打印文本:

yAxisText.text("Temperature, º" + temp)

这样，当您调用 update 时，只需更改 temp 即可:

temp = "C";
update();

这是您的工作代码:

<script src="https://d3js.org/d3.v4.min.js"></script>
<style>
  .axis--x path {
    display: none;
  }
  
  .line {
    fill: none;
    stroke: steelblue;
    stroke-width: 1.5px;
  }

</style>
<button>Click me</button>
<svg width="960" height="500"></svg>
<!--<script src="d3.v4.js"></script>-->

<script>
  var svg = d3.select("svg"),
    margin = {
      top: 20,
      right: 80,
      bottom: 30,
      left: 50
    },
    width = svg.attr("width") - margin.left - margin.right,
    height = svg.attr("height") - margin.top - margin.bottom,
    g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");

  var parseTime = d3.timeParse("%Y%m%d");

  var x = d3.scaleTime().range([0, width]),
    y = d3.scaleLinear().range([height, 0]),
    z = d3.scaleOrdinal(d3.schemeCategory10);

  var line = d3.line()
    .curve(d3.curveBasis)
    .x(function(d) {
      return x(d.date);
    })
    .y(function(d) {
      return y(d.temperature);
    });

  var data = [{
    "date": "1116156400000",
    "Old York": 63.4,
    "San Francisco": 62.7,
    "Austin": 72.2
  }, {
    "date": "1167692400000",
    "Old York": 58.0,
    "San Francisco": 59.9,
    "Austin": 67.7
  }, {
    "date": "1199228400000",
    "Old York": 53.3,
    "San Francisco": 59.1,
    "Austin": 69.4
  }, {
    "date": "1230850800000",
    "Old York": 55.7,
    "San Francisco": 58.8,
    "Austin": 68.0
  }, {
    "date": "1262386800000",
    "Old York": 62.3,
    "San Francisco": 55.1,
    "Austin": 71.9
  }];

  var data2 = [{
    "date": "1136156400000",
    "New York": 263.4,
    "San Francisco": 262.7,
    "Austin": 372.2
  }, {
    "date": "1167692400000",
    "New York": 458.0,
    "San Francisco": 259.9,
    "Austin": -367.7
  }, {
    "date": "1199228400000",
    "New York": 153.3,
    "San Francisco": 259.1,
    "Austin": 369.4
  }, {
    "date": "1230850800000",
    "New York": 155.7,
    "San Francisco": 258.8,
    "Austin": 368.0
  }, {
    "date": "1262386800000",
    "New York": 162.3,
    "San Francisco": 255.1,
    "Austin": 371.9
  }];


  // d3.tsv("data.tsv", type, function (error, data) {
  //     if (error) throw error;

  data.columns = ["date", "Old York", "San Francisco", "Austin"];

  var cities = data.columns.slice(1).map(function(id) {
    return {
      id: id,
      values: data.map(function(d) {
        return {
          date: d.date,
          temperature: d[id]
        };
      })
    };
  });

  x.domain(d3.extent(data, function(d) {
    return d.date;
  }));

  y.domain([
    d3.min(cities, function(c) {
      return d3.min(c.values, function(d) {
        return d.temperature;
      });
    }),
    d3.max(cities, function(c) {
      return d3.max(c.values, function(d) {
        return d.temperature;
      });
    })
  ]);
  g.append("g")
    .attr("class", "axis axis--x")
    .attr("transform", "translate(0," + height + ")")
    .call(d3.axisBottom(x));
  var gY = g.append("g")
    .attr("class", "axis axis--y")
    .call(d3.axisLeft(y));

  var yAxisText = gY.append("text")
    .attr("transform", "rotate(-90)")
    .attr("y", 6)
    .attr("dy", "0.71em")
    .attr("fill", "#000");
    
    var temp = "F";

  update();
  d3.select("button").on("click", function() {
    // cities.splice(0, 1);
    data = data2;
    data.columns = ["date", "New York", "San Francisco", "Austin"];
	temp = "C";
    //            console.log(JSON.stringify(cities));
    update();
  });

  function update() {
    //        data.columns = ["date", "New York", "San Francisco", "Austin"];
    cities = data.columns.slice(1).map(function(id) {
      return {
        id: id,
        values: data.map(function(d) {
          return {
            date: d.date,
            temperature: d[id]
          };
        })
      };
    });



    x.domain(d3.extent(data, function(d) {
      return d.date;
    }));
    y.domain([
      d3.min(cities, function(c) {
        return d3.min(c.values, function(d) {
          return d.temperature;
        });
      }),
      d3.max(cities, function(c) {
        return d3.max(c.values, function(d) {
          return d.temperature;
        });
      })
    ]);
    z.domain(cities.map(function(c) {
      return c.id;
    }));

    var city = g.selectAll(".city")
      .data(cities);

    // var text = g.selectAll(".text")
    //     .data(texts);

    city.exit().remove();

    var cityEnter = city.enter().append("g")
      .attr("class", "city");

    cityEnter.append("path")
      .attr("class", "line")
      .attr("d", function(d) {
        return line(d.values);
      })
      .style("stroke", function(d) {
        return z(d.id);
      });


    city = cityEnter.merge(city);

    cityEnter.append("text")
      //        city.append("text")
      .datum(function(d) {
        return {
          id: d.id,
          value: d.values[d.values.length - 1]
        };
      })
      .attr("transform", function(d) {
        return "translate(" + x(d.value.date) + "," + y(d.value.temperature) + ")";
      })
      .attr("x", 3)
      .attr("dy", "0.35em")
      .style("font", "10px sans-serif")
      .text(function(d) {
        return d.id;
      });


    city.select("path")
      //            .transition().duration(1000)
      .attr("d", function(d) {
        return line(d.values);
      });

    city.select("text").datum(function(d) {
        return {
          id: d.id,
          value: d.values[d.values.length - 1]
        };
      })
      .text(function(d) {
        return d.id;
      })
      //            .transition().duration(1000)
      .attr("transform", function(d) {
        return "translate(" + x(d.value.date) + "," + y(d.value.temperature) + ")";
      });

    svg.select(".axis--y")
      .transition().duration(1000)
      .call(d3.axisLeft(y));

    svg.select(".axis--x")
      .transition().duration(1000)
      .call(d3.axisBottom(x));

		    yAxisText.text("Temperature, º" + temp)

  }

</script>