["python","math","numpy","logarithm"]
NumPy: Logarithm with base n

From the numpy documentation on logarithms, I have found functions to take the logarithm with base e, 2, and 10: import numpy as np np.log(np.e**3) #3.0 np.log2(2**3) #3.0 np.log10(10**3) #3.0 However, how do I take the logarithm with base n (e.g. 42) in numpy?
If you have numpy 1.23 or later, you can use np.emath.logn: import numpy as np array = np.array([74088, 3111696]) # = [42^3, 42^4] base = 42 exponent = np.emath.logn(base, array) # = [3, 4] If your version of numpy is older: To get the logarithm with a custom base using math.log: import math number = 74088 # = 42^3 base = 42 exponent = math.log(number, base) # = 3 To get the logarithm with a custom base using numpy.log: import numpy as np array = np.array([74088, 3111696]) # = [42^3, 42^4] base = 42 exponent = np.log(array) / np.log(base) # = [3, 4] Which uses the logarithm base change rule: