Python 来自 Pandas 数据帧的具有不同大小、标记和颜色的散点图
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Scatterplot with different size, marker, and color from pandas dataframe
提问by Kexin Xu
I am trying to do a scatter plot with speed over meters for each point where marker indicate different types, size indicate different weights and color indicate how old a point is over 10 minutes scale. However, I was only able to plot by size so far.
我正在尝试为每个点绘制速度超过米的散点图，其中标记表示不同的类型，大小表示不同的权重，颜色表示一个点超过 10 分钟的规模。但是，到目前为止，我只能按大小进行绘图。
Any help is highly appreciated.
任何帮助都受到高度赞赏。
x = {'speed': [10, 15, 20, 18, 19], 'meters' : [122, 150, 190, 230, 300], 'type': ['phone', 'phone', 'gps', 'gps', 'car'], 'weight': [0.2, 0.3, 0.1, 0.85, 0.0], 'old': [1, 2, 4, 5, 8]}
m = pd.DataFrame(x)
plt.scatter(m.meters, m.speed, s = 30* m.weight)
mkr_dict = {'gps': 'x', 'phone': '+', 'car': 'o'}
meters speed type weight old
0 122 10 phone 0.20 1
1 150 15 phone 0.30 2
2 190 20 gps 0.10 4
3 230 18 gps 0.85 5
4 300 19 car 0.00 8
Updated question:
更新的问题：
I am trying to add colorbar to the color scale based on old. it worked when I plot against the entire dataset but failed after trying to add marker for each subset. Any idea?
我正在尝试将颜色条添加到基于旧的色标中。当我针对整个数据集进行绘图时它起作用，但在尝试为每个子集添加标记后失败。任何的想法？
plt.scatter(m.meters, m.speed, s = 30* m.weight, c=m.old)
cbar = plt.colorbar(ticks = [0, 5, 10])
cbar.ax.set_yticklabels(['New','5mins', '10mins'])
TypeError: You must first set_array for mappable
类型错误：您必须先为可映射设置 set_array
采纳答案by cphlewis
scattercan only do one kind of marker at a time, so you have to plot the different types separately. Fortunately pandas makes this easy:
scatter一次只能做一种标记，所以你必须分别绘制不同的类型。幸运的是，pandas 让这一切变得简单：
import matplotlib.pyplot as plt
import pandas as pd
x = {'speed': [10, 15, 20, 18, 19],
'meters' : [122, 150, 190, 230, 300],
'type': ['phone', 'phone', 'gps', 'gps', 'car'],
'weight': [0.2, 0.3, 0.1, 0.85, 0.0],
'old': [1, 2, 4, 5, 8]}
m = pd.DataFrame(x)
mkr_dict = {'gps': 'x', 'phone': '+', 'car': 'o'}
for kind in mkr_dict:
d = m[m.type==kind]
plt.scatter(d.meters, d.speed,
s = 100* d.weight,
c = d.old,
marker = mkr_dict[kind])
plt.show()
.... Where's the car? Well, the weight is 0.0 in the original test data, and we're using weight for marker-size, so: can't see it.
……车呢？嗯，原始测试数据中的权重是 0.0，我们使用权重作为标记大小，所以：看不到它。
回答by xnx
If you have just a few points, as here, you can pass a list of floats to the cargument:
如果您只有几点，如这里，您可以将浮点数列表传递给c参数：
colors = ['r', 'b', 'k', 'g', 'm']
plt.scatter(m.meters, m.speed, s=30*m.weight, vmin=0, vmax=10, cmap=cm)
to have your points coloured in the order given. Alternatively, to use a colormap:
按照给定的顺序对您的点进行着色。或者，要使用颜色图：
cm = plt.cm.get_cmap('hot') # or your colormap of choice
plt.scatter(m.meters, m.speed, s=30*m.weight, c=m.old, cmap=cm)
To change the marker shapes, you either need to add your own Patches, or add one point at a time: e.g.
要更改标记形状，您需要添加自己的Patches，或者一次添加一个点：例如
markers = ['^', 'o', 'v', 's', 'd']
for px, py, c, s, t in zip(m.meters, m.speed, m.old, m.weight, markers):
plt.scatter(px, py, marker=t, c=cm(c/10.), vmin=0, vmax=10, s=400*s+100)
plt.show()
(I've scaled the m.weightto a different range to see the 5th point, which would otherwise have size 0.0).
（我已将 缩放m.weight到不同的范围以查看第 5 个点，否则该点的大小为 0.0）。
