所以我想将以下Python代码翻译成VBA(只是为了说明问题的玩具示例,详细信息省略)。
def numerical_integration(fun, a, b):
"""
:param fun: callable
:param a, b: float
:return: float
"""
# do something based on both fun and a, b
res = ...
return res
def h(x, k):
"""
helper func
:param x: float, main arg
:param k: float, side param
:return: float
"""
# calc based on both x and k
res = ...
return res
def main_function(k):
"""
:param k: float
:return: float
"""
a, b = 0.0, 1.0
res = numerical_integration(fun=lambda x: h(x, k), a=a, b=b)
return res
问题是我不知道如何在 VBA 中正确传递“部分”函数作为参数。我发现如何在 VBA 中传递“整个”函数 this post 。这个想法是将函数作为字符串传递,然后让 VBA 计算该字符串(我猜类似于 Python eval
等价物?)。但我不知道如果我的函数是部分的,即我希望它仅在第一个参数上成为一个函数,例如 lambda x: f(x, k) ,其中第二个参数位于主函数的上下文中。
感谢您提前提出任何建议。
最佳答案
我不了解Python和“部分”函数,但我尝试使用对象来替换它。 我创建了一个类模块,试图模仿“部分”函数,具有可选参数和默认值。
Public defaultX As Double
Public defaultY As Double
Public Function h(Optional x As Variant, Optional y As Variant) As Double
' The IsMissing() function below only works with the Variant datatype.
If (IsMissing(x)) Then
x = defaultX
End If
If (IsMissing(y)) Then
y = defaultY
End If
h = x + y
End Function
然后我决定在 numeric_integration 中使用“CallByName”函数。 这是主模块代码:
Public Function numerical_integration(fun As clsWhatEver, funName As String, a As Double, b As Double) As Integer
Dim r1 As Double, r2 As Double
' CallByName on the "fun" object, calling the "funName" function.
' Right after "vbMethod", the parameter is left empty
' (assuming default value for it was already set).
r1 = CallByName(fun, funName, VbMethod, , a)
r2 = CallByName(fun, funName, VbMethod, , b)
numerical_integration = r1 + r2
End Function
Public Function main_function(k As Double) As Double
Dim res As Double
Dim a As Double, b As Double
a = 0#
b = 1#
Dim oWE As New clsWhatEver
' Sets the default value for the first parameter of the "h" function.
oWE.defaultX = k
res = numerical_integration(oWE, "h", a, b)
main_function = res
End Function
关于python - VBA如何使用部分参数调用另一个函数内的函数,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/57301376/