我在 python 中遇到值错误的问题

Question

这是我绘制应力-应变曲线的代码

import matplotlib.pyplot as plt
import numpy as np
import math
from scipy.interpolate import interp1d
from matplotlib.offsetbox import AnchoredText
import pandas as pd


#both strain is a column in the given dataframe, and I manually calculated stress
df_1 = pd.read_csv('1045.csv',skiprows=25,header=[0,1])
print(df_1.head())

A1 = 40.602*(10e-6)
stress1 = ((df_1.Load)/A1)


plt.figure(figsize=(12,9))
plt.plot(df_1.Strain1.values,df_1.Load.values,'g')
plt.ylabel('stress(Pa)',fontsize=13)
plt.xlabel('Strain(%)',fontsize=13)
plt.xticks(np.arange(-6e-5,0.15,step=0.005),rotation = 45)
plt.yticks(np.arange(0,42000,step=1000))

strain = df_1.Strain1.values
stress = np.array(((df_1.Load.values)/A1))
strain = np.array((df_1.Strain1.values))

LinearLimit=1
Strain_values_linear = np.linspace(strain[0], strain[LinearLimit], num=50, endpoint=True)
Strain_values_eng = np.linspace(strain[LinearLimit], strain[-1], num=50, endpoint=True)
f1 = interp1d(strain, stress, fill_value='extrapolate')
f2 = interp1d(strain, stress, kind=3, fill_value='extrapolate')

现在我不断收到一个值错误：“x 和 y 数组沿插值轴的长度必须相等。”我不明白这个……我打印了应变和应力的形状，它们是一样的顺便说一句，这是 csv 文件的屏幕截图： enter image description here

Answer 1

您可能正在传递一个形状为 (..., N) 的数组作为第一个参数（意味着 strain 具有 (..., N) 形式的形状）。 SciPy 不允许这样做并抛出 ValueError。有关详细信息，请参阅 documentation。如果 strain 数组中有多个向量，则应该运行一个 for 循环。下面的代码应该可以工作，考虑到你想为 strain 中的每一行插入 1 个函数（并且该应变是一个二维数组。如果不是，你可以使用 strain.reshape(-1, N) 轻松转换它):

import matplotlib.pyplot as plt
import numpy as np
import math
from scipy.interpolate import interp1d
from matplotlib.offsetbox import AnchoredText
import pandas as pd


#both strain is a column in the given dataframe, and I manually calculated stress
df_1 = pd.read_csv('1045.csv',skiprows=25,header=[0,1])
print(df_1.head())

A1 = 40.602*(10e-6)
stress1 = ((df_1.Load)/A1)


plt.figure(figsize=(12,9))
plt.plot(df_1.Strain1.values,df_1.Load.values,'g')
plt.ylabel('stress(Pa)',fontsize=13)
plt.xlabel('Strain(%)',fontsize=13)
plt.xticks(np.arange(-6e-5,0.15,step=0.005),rotation = 45)
plt.yticks(np.arange(0,42000,step=1000))

strain = df_1.Strain1.values
stress = np.array(((df_1.Load.values)/A1))
strain = np.array((df_1.Strain1.values))

LinearLimit=1
Strain_values_linear = np.linspace(strain[0], strain[LinearLimit], num=50, endpoint=True)
Strain_values_eng = np.linspace(strain[LinearLimit], strain[-1], num=50, endpoint=True)

f1, f2 = [], []
for row in range(len(strain)):
    f1.append(interp1d(strain[row], stress, fill_value='extrapolate'))
    f2.append(interp1d(strain[row], stress, kind=3, fill_value='extrapolate'))

编辑：根据评论，您有 strain 个形状为 (222, 1) 的数组。这意味着您已经有一个矢量，但形状与 SciPy 接受的不兼容。在这种情况下，您将必须重塑应变和应力数组以具有 (N,) 形式的形状。以下代码应该有效：

import matplotlib.pyplot as plt
import numpy as np
import math
from scipy.interpolate import interp1d
from matplotlib.offsetbox import AnchoredText
import pandas as pd


#both strain is a column in the given dataframe, and I manually calculated stress
df_1 = pd.read_csv('1045.csv',skiprows=25,header=[0,1])
print(df_1.head())

A1 = 40.602*(10e-6)
stress1 = ((df_1.Load)/A1)


plt.figure(figsize=(12,9))
plt.plot(df_1.Strain1.values,df_1.Load.values,'g')
plt.ylabel('stress(Pa)',fontsize=13)
plt.xlabel('Strain(%)',fontsize=13)
plt.xticks(np.arange(-6e-5,0.15,step=0.005),rotation = 45)
plt.yticks(np.arange(0,42000,step=1000))

strain = df_1.Strain1.values
stress = np.array(((df_1.Load.values)/A1))
strain = np.array((df_1.Strain1.values))
strain = strain.reshape(-1,)
stress = stress.reshape(-1,)

LinearLimit=1
Strain_values_linear = np.linspace(strain[0], strain[LinearLimit], num=50, endpoint=True)
Strain_values_eng = np.linspace(strain[LinearLimit], strain[-1], num=50, endpoint=True)
f1 = interp1d(strain, stress, fill_value='extrapolate')
f2 = interp1d(strain, stress, kind=3, fill_value='extrapolate')

我在 python 中遇到值错误的问题

I have some problems with a value error in python

python

scipy

valueerror