ValueError: setting an array element with a sequence when trying to plot with matplotlib

Question

当我尝试运行以下代码时：

from matplotlib import pyplot as plt

Xpos = df[df['bound']==1]
Xneg = df[df['bound']==0]
y1, X1 = Xpos['Id'].values, Xpos['seq'].values
y2, X2 = Xneg['Id'].values, Xneg['seq'].values

fig, ax = plt.subplots()
ax.plot(y1, X1 , label='bounded sequences', color='blue')
ax.plot(y2, X2 , label='unbounded sequences', color='red')
plt.show()

我收到这个错误：ValueError: setting an array element with a sequence.
df 的示例输出类似于您找到的 here.
有人可以帮忙吗？
谢谢

Answer 1

这里的问题是您正在尝试绘制列表列表。

为了向您解释这个问题，我创建了一个类似于您正在使用的示例数据集（唯一的区别是序列更短）。这是我用来创建数据集的代码：

df_dict = {
    "Id": [0, 1, 2, 3, 4],
    "seq": [[0, 0, 1, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 1, 0], [0, 0, 1, 0]],
    "bound": [1, 0, 1, 0, 1]
}
df = pd.DataFrame(df_dict)

如果我们现在执行代码的第一部分并打印 X1 变量：

Xpos = df[df['bound']==1]
Xneg = df[df['bound']==0]
y1, X1 = Xpos['Id'].values, Xpos['seq'].values
y2, X2 = Xneg['Id'].values, Xneg['seq'].values
print(X1)

输出将是：

[list([0, 0, 1, 0]) list([0, 0, 1, 0]) list([0, 0, 1, 0])]

如果您想为 X1 绘制的是每个列表的串联，例如[0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0]，这可能会解决您的问题：

import pandas as pd
from matplotlib import pyplot as plt

df_dict = {
    "Id": [0, 1, 2, 3, 4],
    "seq": [[0, 0, 1, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 1, 0], [0, 0, 1, 0]],
    "bound": [1, 0, 1, 0, 1]
}
df = pd.DataFrame(df_dict)

Xpos = df[df['bound']==1]
Xneg = df[df['bound']==0]
print(Xpos)
y1, X1 = Xpos['Id'].values, [elem for sub_list in Xpos['seq'].values for elem in sub_list]
y2, X2 = Xneg['Id'].values, [elem for sub_list in Xneg['seq'].values for elem in sub_list]
print(y1)
print(X1)
fig, ax = plt.subplots()
ax.plot(X1, label='bounded sequences', color='blue')
ax.plot(X2, label='unbounded sequences', color='red')
plt.show()

如果您想要散点图而不是线图，只需将两个 ax.plot 函数替换为以下内容：

ax.scatter(range(len(X1)), X1, label='bounded sequences', color='blue')
ax.scatter(range(len(X2)), X2, label='unbounded sequences', color='red')

ValueError: setting an array element with a sequence when trying to plot with matplotlib

ValueError: setting an array element with a sequence when trying to plot with matplotlib

python

arrays

matplotlib

sequence

valueerror