如何在另一个python文件中使用函数

Question

I made a function called WaveLengthCal(d, T) as below

def WaveLengthCal(d, T):

 import numpy as np

 g=9.8
 k0h=4*np.pi**2/g/T**2*d;

 if k0h>2.72:
    kh=k0h*(1+2*np.exp(-2*k0h))
 else:
    kh=np.sqrt(k0h)*(1+1/16*k0h+11/360*k0h**2)

 NP=10 # number of time of iteration
 L0=g*T**2/2/np.pi
 L=L0*np.tanh(kh)

 if d/L <1/20:
    L=T*np.sqrt(g*d)
 elif d/L>1/2:
    L=L0
 else:
    for i in range(NP):
        L=g*T**2/2/np.pi*np.tanh(2*np.pi*d/L)

 return L

This function works fine if I use this function in the same file as

>>> WaveLengthCal(2,3)
[11.297788563155367]

However, when I tried to use this function in another python file as below,

import WaveLengthCal as wl

L=wl.WaveLengthCal(0.513,2)

it does not work well, it showed an error message as

> Traceback (most recent call last):   File
> "/usr/lib/python3.5/code.py", line 91, in runcode
>     exec(code, self.locals)   File "<input>", line 7, in <module> TypeError: WaveLengthCal() missing 1 required positional argument: 'T'

I am not sure why, as I already put two inputs there, but it keeps on telling me one of the argument is missing. Anyone has any suggestions?

Answer 1

What is the name of the file into which you put your function? It is that name that should be imported. Say:

You have a file named: wavefunctionfile.py with the following content:

def wavefunction(a,b):
    print(a)
    print(b)
    return a+b

You can now start python in the same directory as the file and do this:

>>> import wavefunctionfile as w
>>> w.wavefunction(3,4)

This will output

3
4
7

Answer 2

from WaveLengthCalFile import WaveLengthCal should work, but I feel like if the above doesn't work then there is something else going on...

Note that you will need to configure your IDE to work with this. In Pycharm you can right click the directory your WaveLengthCalFile is in and click "Mark as Source"

In the above picture, I import a function called a_func from a file called moonbase.py, which demonstrates your required functionality exactly