C Preprocessor Macro equivalent for Python

Is there a way? Yes. There's always a way. Should you do it? Probably not.

Just define a function that does what you want. If you are just concerned about code getting really long and want a one-liner, you can use a lambda function.

long_f = lambda a,b,c: a*0.123 + a*b*5.6 - 0.235*c + 7.23*c - 5*a*a + 1.5
long_f(1,2,3) == 28.808

And of course your first example is already way prettier in Python.

for i in range(a,b):
    ...

Edit: for completeness, I should answer the question as asked. If you ABSOLUTELY MUST preproccess your Python code, you can use any programming language designed for templating things like web pages. For example, I've heard of PHP being used for preprocessing code. Instead of HTML, you write your code. When you want something preprocessesed, you do your PHP blocks.

There is nothing in Python 100% equivalent to macro in C. But there is a makeshift using exec().

Say we want to compute the addition and multiplication of all the elements of a 4-D matrix. Normally we can define the functions like

import numpy as np

def Addition(matrix):
    result=0
    for i in range(matrix.shape[0]):
        for j in range(matrix.shape[1]):
            for k in range(matrix.shape[2]):
                for l in range(matrix.shape[3]):
                    result+=matrix[i,j,k,l]
    return result

def Multiplication(matrix):
    result=1
    for i in range(matrix.shape[0]):
        for j in range(matrix.shape[1]):
            for k in range(matrix.shape[2]):
                for l in range(matrix.shape[3]):
                    result*=matrix[i,j,k,l]
    return result

The 4-fold loop appears twice but I want it to appear only once for conciseness. In C/C++, we would replace it with a macro like

#define Loop\
    for (i=0;i<imax;i++)\
        for (j=0;j<jmax;j++)\
        ........

In Python, we can use exec() instead. This function takes in a string and execute it as a command. So the codes become

import numpy as np

string='''
for i in range(matrix.shape[0]):
    for j in range(matrix.shape[1]):
        for k in range(matrix.shape[2]):
            for l in range(matrix.shape[3]):
                __replacement__
'''

def Addition(matrix):
    result=np.zeros([1])
    exec(string.replace("__replacement__","result[0]+=matrix[i,j,k,l]"))
    return result[0]

def Multiplication(matrix):
    result=np.zeros([1])+1
    exec(string.replace("__replacement__","result[0]*=matrix[i,j,k,l]"))
    return result[0]

Here, the 4-fold loop appears only once as a global string variable. BUT BE WARNED. There is one problem: The result must be a np.array. If you initialize result as an ordinary float like result=0. and result=1., the exec() function will not change it and the initial values 0 and 1 will be returned in the end. This is probably a problem with the difference between reference and value. Besides, I don't expect any performance gain from this replacement. The only advantage is convenience in coding replicated commands, which may be useful in some scenarios.

The answer is no, in python you cannot actually include code "in-line/stream/whatever" like in C, C++, PL/1, Assembler, etc.. Implementation of this directive happens during an initial macro/processor/keyword scan or compiler pass. It could easily be added, and there are lots of reasons one might wish to include code directly inline without it being a function or module. This feature would make it possible to use the same snippet of code in multiple class or function definitions. For example defining the same GTK+ elements within multiple classes are a pain without it. This lack of ability has nothing to do with interpretation, because it occurs prior to syntactic analysis. It is not included in interpreted script languages such as Perl and Python simply because the developers do not want to make the feature available.

import inspect

frame = inspect.currentframe()
print(f"{frame.f_lineno}\tdebugtext")
l = lambda: frame.f_lineno
print(f"{l()}\tdebugtext")