Python：float() 参数必须是字符串或数字，而不是“interp2d”

Question

此代码返回错误“float() 参数必须是字符串或数字，而不是 'interp2d'”。我正在尝试学习如何在给定数组中的一些值的情况下插入值以填充数组（对不起，措辞不好）。我是在搞乱 interp2d 函数的语法还是什么？

import numpy as np
import matplotlib.pyplot as plt
from netCDF4 import Dataset
import scipy as sp

GCM_file = '/Users/Robert/Documents/Python Scripts/GCMfiles/ATM_echc0003_1979_2008.nc'
fh = Dataset(GCM_file, mode = 'r')

pressure = fh.variables['lev'][:]
lats = fh.variables['lat'][:]
temp = np.mean(fh.variables['t'][0,:,:,:,:], axis = (0, 3))
potential_temp = np.zeros((np.size(temp,axis=0), np.size(temp,axis=1)))

P0 = pressure[0] 
#plt.figure(0)
for j in range(0, 96):
    potential_temp[:,j] = temp[:, j] * (P0/ pressure[:]) ** .238


potential_temp_view = potential_temp.view()

temp_view = temp.view()

combo_t_and_pt = np.dstack((potential_temp_view,temp_view))
combo_view = combo_t_and_pt.view()

pt_and_t_flat=np.reshape(combo_view, (26*96,2))
t_flat = temp.flatten()
pt_flat = potential_temp.flatten()

temp_grid = np.zeros((2496,96))

for j in range(0, 2496):
    if j <= 95:
        temp_grid[j,j] = t_flat[j]
    else:
            temp_grid[j, j % 96] = t_flat[j]

'''Now you have the un-interpolated grid of all your values of t as a function of potential temp and latitude, so you have to interpolate the rest somehow....?'''

xlist = lats
ylist = pt_flat

X,Y = np.meshgrid(xlist,ylist)



temp_cubic = sp.interpolate.interp2d(xlist,ylist, temp_grid, kind = 'cubic')
#temp_linear= griddata(temp_grid, (X,Y), method = 'linear')
#temp_quintic = griddata(temp_grid, (X,Y), method = 'cubic')

plt.figure(0)
plt.contourf(X,Y, temp_cubic, 20)

编辑：向我指出了这个错误。我将插值行中的代码更改为此代码，但仍然出现错误，显示为“ValueError：输入数据无效”。这是回溯：

runfile('C:/Users/Robert/Documents/Python Scripts/attempt at defining potential temperature.py', wdir='C:/Users/Robert/Documents/Python Scripts')
Traceback (most recent call last):
  File "<ipython-input-27-1ffd3fcc3aa1>", line 1, in <module>
    runfile('C:/Users/Robert/Documents/Python Scripts/attempt at defining potential temperature.py', wdir='C:/Users/Robert/Documents/Python Scripts')
  File "C:\Users\Robert\Anaconda3\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 699, in runfile
    execfile(filename, namespace)
  File "C:\Users\Robert\Anaconda3\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 88, in execfile
    exec(compile(open(filename, 'rb').read(), filename, 'exec'), namespace)
  File "C:/Users/Robert/Documents/Python Scripts/attempt at defining potential temperature.py", line 62, in <module>
    Z = temp_cubic(xlist,ylist)
  File "C:\Users\Robert\Anaconda3\lib\site-packages\scipy\interpolate\interpolate.py", line 292, in __call__
    z = fitpack.bisplev(x, y, self.tck, dx, dy)
  File "C:\Users\Robert\Anaconda3\lib\site-packages\scipy\interpolate\fitpack.py", line 1048, in bisplev
    raise ValueError("Invalid input data")":

temp_cubic = sp.interpolate.interp2d(xlist, ylist, temp_grid, kind = 'cubic')

ylist = np.linspace(np.min(pt_flat), np.max(pt_flat), .01)

X,Y = np.meshgrid(xlist,ylist)
Z = temp_cubic(xlist,ylist)
plt.contourf(X,Y, Z, 20)

Answer 1

问题出在下面一行。 interp2d 返回一个插值函数。但是，您使用它代替了 countourf 的 Z 参数，它应该是一个浮点矩阵。详情请见contourf doc。

特别是：

contour(X,Y,Z,N)
make a contour plot of an array Z.
X, Y specify the (x, y) coordinates of the surface
X and Y must both be 2-D with the same shape as Z,
  or they must both be 1-D such that
  len(X) is the number of columns in Z and
  len(Y) is the number of rows in Z.
contour up to N automatically-chosen levels.

简而言之，我相信您希望将函数应用于 X 和 Y 以生成您作为第三个参数传入的数组。

感谢 matplotlib 文档和 kindall 显示我的其他可能性的概念错误。