array    : [array_like]Input array or object.
out      : [ndarray, optional]Output array with same dimensions as Input array, 
         placed with result.
**kwargs : allows you to pass keyword variable length of argument to a function. 
         It is used when we want to handle named argument in a function.
where    : [array_like, optional]True value means to calculate the universal 
         functions(ufunc) at that position, False value means to leave the value in the 
         output alone.

An array with Base-10 logarithmic value of x; 
where x belongs to all elements of input array. 

# Python program explaining
# log10() function

import numpy as np

in_array = [1, 3, 5, 10**8]
print ("Input array : ", in_array)

out_array = np.log10(in_array)
print ("Output array : ", out_array)


print("\nnp.log10(4**4) : ", np.log10(100**4))
print("np.log10(2**8) : ", np.log10(10**8))

Input array :  [1, 3, 5, 100000000]
Output array :  [ 0.          0.47712125  0.69897     8.        ]

np.log10(4**4) :  8.0
np.log10(2**8) :  8.0

# Python program showing
# Graphical representation of 
# log10() function

import numpy as np
import matplotlib.pyplot as plt

in_array = [1, 2, 3, 4, 5]
out_array = np.log10(in_array)

print ("out_array : ", out_array)

plt.plot(in_array, in_array, color = 'blue', marker = "*")

# red for numpy.log10()
plt.plot(out_array, in_array, color = 'red', marker = "o")
plt.title("numpy.log10()")
plt.xlabel("out_array")
plt.ylabel("in_array")
plt.show()  

out_array :  [ 0.          0.30103     0.47712125  0.60205999  0.69897   ]