renaming files in a directory using python or R -

i went across similar questions of renaming files in directory using python.

i have these files in directory want rename:

    -statistical_analysis_with_r     -statistical_pattern_recognition_3rd_edition      -statistical analysis r     -statistical pattern recognition 3rd edition 

for wrote script in windows:

def naming(so):     import re     w=re.split('[ _]+',so)     r=[]     in w:         r.append(i.capitalize())     print(' '.join(r))      import os c in os.listdir(os.getcwd()):     if c.endswith(".pdf"):         os.rename(c,naming(c)) print(os.listdir(os.getcwd())) 

but getting error:

statistical analysis r.pdf traceback (most recent call last):    file "<ipython-input-79-d7f645d6d3e5>", line 4, in <module>     os.rename(c,naming(c))  typeerror: rename: can't specify none path argument 

can what's going on?

and doing same thing using r (www.r-project.org)? 

loads of in advance.

your naming function doesn't return name, prints out name , returns none. that's why you're getting error none.

change this: print(' '.join(r))

to this: return ' '.join(r)