my code looks like:

list_var = ['rh','temp','tl','Tt','DPD','PAR']
for L in range(1, len(list_var)):for subset in itertools.combinations(list_var, L):f = 'inf ~ {} + C(area)'.format(' * '.join(list(subset)))

error 'range' object is not callable jumped up even I changed len(list_var) into a number. Can you identify the problem and fix it? Thank you in advance!!!

I can reproduce the issue when assigning the range name to a range instanciated object:

>>> range = range(10)
>>> range(1)
Traceback (most recent call last):File "<string>", line 301, in runcodeFile "<interactive input>", line 1, in <module>
TypeError: 'range' object is not callable

you probably reassigned the name earlier in your code, triggering this exact error.

A quick & dirty fix is:

del range