在pandas / python中绘制平行坐标

Question

我正在尝试在python中使用pandas来绘制以下高维数据： http://i.stack.imgur.com/34nbR.jpg

这是我的代码：

import pandas
from pandas.tools.plotting import parallel_coordinates

data = pandas.read_csv('ParaCoords.csv')
parallel_coordinates(data,'Name')

代码无法绘制数据，Traceback错误以：

结束

Keyerror: 'Name'

parallel_coordinates应该说/做的第二个参数是什么？ 如何成功绘制数据？

Answer 1

第二个参数应该是定义class的列名。想想['dog', 'dog', 'cat', 'bird', 'cat', 'dog']。

在example online中，他们使用'Name'作为第二个参数，因为这是一个定义虹膜名称的列

文档

Signature: parallel_coordinates(*args, **kwargs)
Docstring:
Parallel coordinates plotting.

Parameters
----------
frame: DataFrame
class_column: str
    Column name containing class names
cols: list, optional
    A list of column names to use
ax: matplotlib.axis, optional
    matplotlib axis object
color: list or tuple, optional
    Colors to use for the different classes
use_columns: bool, optional
    If true, columns will be used as xticks
xticks: list or tuple, optional
    A list of values to use for xticks
colormap: str or matplotlib colormap, default None
    Colormap to use for line colors.
axvlines: bool, optional
    If true, vertical lines will be added at each xtick
axvlines_kwds: keywords, optional
    Options to be passed to axvline method for vertical lines
kwds: keywords
    Options to pass to matplotlib plotting method

Answer 2

您download from UCI没有标头的iris.data文件。要使pandas示例有效，您必须将标题明确指定为列名：

from pandas.tools.plotting import parallel_coordinates
# The iris.data file from UCI does not have headers,
# so we have to assign the column names explicitly.
data = pd.read_csv("data-iris-for-pandas/iris.data")
data.columns=["x1","x2","x3","x4","Name"]
plt.figure()
parallel_coordinates(data,"Name")

基本上，pandas文档不完整。有人在没有让我们知道的情况下将列名放入数据框中。