title: Plotly lines using start and end dates
body: <p>I have a DataFrame with the columns: <em>start date</em>, <em>end date</em>, and <em>value</em>. How can I plot one line for each <em>start-end date</em> in Plotly?</p>
  
  <p>Example:</p>
  
  <pre><code>import pandas as pd
  import plotly.express as px
  df = pd.DataFrame({"start date": [1,2,3,4], "end date":[8,7,4,9], "value":[11,3,11,4]})
  fig = px.line(df, x=["start date","end date"], y="value")
  fig.show()
  </code></pre>
  
  <p>In this case, there are only two lines for the columns <em>start date</em> and <em>end date</em>. However, what I'm looking for is 1 line for each <em>start-end date</em>. I tried with the parameter <em>color="value"</em> but, in value 11 it only plots 1 line. I could print it with simple plot of <em>plt</em> as:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  x = [df["start date"], df["end date"]]
  y = [df["value"], df["value"]]
  plt.plot(x, y)
  plt.show()
  </code></pre>