为条形图中的轨迹编写函数

Question

我创建了一个数据透视表：

df = data.pivot_table(index='col_A', columns='col_B', values='col_C', fill_value=0)

数据帧df是10 * 25数据帧。我想将单个图形中的所有列绘制为迹线。但是，为所有25条跟踪编写代码会非常繁琐。有没有办法可以编写如下函数：

import plotly.plotly as py
import plotly.tools as tls
from plotly.offline import download_plotlyjs, init_notebook_mode, plot, iplot
import plotly.graph_objs as go
init_notebook_mode(connected=True)
iplot([go.Bars(x=df.index, y=df[col], name=col for col in df.columns)])

上面的代码给出了语法无效的错误。

Answer 1

我为您提供了更好理解的示例：

# import what we need
import plotly
import plotly.graph_objs as go
import pandas as pd
# Create DataFrame
df = pd.DataFrame({"A":[1,1,1,0],
                   "B":[1,1,0,0],
                   "C":[1,0,0,0]
                   })
# Convert names of columns in a list
traceslist = df.columns.tolist()
# Check list
print(traceslist)
# Create a function that will create as many traces for us as we need
def tracing(column):
   trace = go.Bar(
         x = df.index,
         y = df[column],
         # Parameters above specify what you would see if hover on any column
         name = column,
         text=column,
         textposition='auto',
         hoverinfo="x+y")
   return trace
# Create data
data = []
# Fill out data with our traces
for i in range(len(traceslist)):
   eachtrace = tracing(traceslist[i])
   data.append(eachtrace)
# Optional: create layout
layout = go.Layout(
      # Set title to plot
      title = "Bam!",
      # Choose one of the barmode below and comment another
      barmode="stack",
      #barmode="group"
      )
# Create figure with all we need to plot
fig = go.Figure(data=data, layout=layout)
# Use offline plot without connection to plotly site
plotly.offline.plot(fig, filename='Bam.html')

在上面的代码中，只需使用函数来创建traces。然后使用for循环来获取traces中的所有data。你可以在这里看到两个barmode参数有什么区别： 1）barmode="stack"; 2）barmode="group"。

你可以创建一个更漂亮的图（查看bar chart的官方文档），只需指定其他参数。