title: Custom Plotly Markers based on variable value
body: <p>I am using the following code to create a simple plotly line chart in Python. I have two variables (at the bottom of the code):</p>
  
  <pre><code>ctime
  amount
  </code></pre>
  
  <p>ctime just using the current time for each element in amount; there are 10 times
  amount is a contained of amounts ranging from 0-1000; the are ten amounts</p>
  
  <p>I want to color my plot markers in the following way:</p>
  
  <p>amount is less than 300; that specific marker for that value will be green
  amount is between 300 and 400; that specific marker for that value will be yellow
  amount is greater than 400; that specific marker for that value will be red</p>
  
  <p>Is there any way I can build in a conditional type handler for this?</p>
  
  <pre><code>layout = Layout(
      title='Current Amount',
      titlefont=Font(
          family='"Open sans", verdana, arial, sans-serif',
          size=17,
          color='#444'
      ),
      font=Font(
          family='"Open sans", verdana, arial, sans-serif',
          size=12,
          color='#444'
      ),
      showlegend=True,
      autosize=True,
      width=803,
      height=566,
      xaxis=XAxis(
          title='Time',
          titlefont=Font(
              family='"Open sans", verdana, arial, sans-serif',
              size=14,
              color='#444'
          ),
          range=[1418632334984.89, 1418632334986.89],
          domain=[0, 1],
          type='date',
          rangemode='normal',
          autorange=True,
          showgrid=False,
          zeroline=False,
          showline=True,
          autotick=True,
          nticks=0,
          ticks='inside',
          showticklabels=True,
          tick0=0,
          dtick=1,
          ticklen=5,
          tickwidth=1,
          tickcolor='#444',
          tickangle='auto',
          tickfont=Font(
              family='"Open sans", verdana, arial, sans-serif',
              size=12,
              color='#444'
          ),
          mirror='allticks',
          linecolor='rgb(34,34,34)',
          linewidth=1,
          anchor='y',
          side='bottom'
      ),
      yaxis=YAxis(
          title='GHI (W/m2)',
          titlefont=Font(
              family='"Open sans", verdana, arial, sans-serif',
              size=14,
              color='#444'
          ),
          range=[-5.968375815056313, 57.068375815056314],
          domain=[0, 1],
          type='linear',
          rangemode='normal',
          autorange=True,
          showgrid=False,
          zeroline=False,
          showline=True,
          autotick=True,
          nticks=0,
          ticks='inside',
          showticklabels=True,
          tick0=0,
          dtick=1,
          ticklen=5,
          tickwidth=1,
          tickcolor='#444',
          tickangle='auto',
          tickfont=Font(
              family='"Open sans", verdana, arial, sans-serif',
              size=12,
              color='#444'
          ),
          exponentformat='B',
          showexponent='all',
          mirror='allticks',
          linecolor='rgb(34,34,34)',
          linewidth=1,
          anchor='x',
          side='left'
      ),
      legend=Legend(
          x=1,
          y=1.02,
          traceorder='normal',
          font=Font(
              family='"Open sans", verdana, arial, sans-serif',
              size=12,
              color='#444'
          ),
          bgcolor='rgba(255, 255, 255, 0.5)',
          bordercolor='#444',
          borderwidth=0,
          xanchor='left',
          yanchor='auto'
      )
  )
  
  
  new_data = Scatter(x=ctime, y=amount)
  data = Data( [ new_data ] )
  </code></pre>