Find chemical symbols and surround them with \ce{ Symbol }

sym2ce.py

#!/usr/bin/env python3
# Find chemical symbols and surround them with \ce{ Symbol }
# Problem words: I, HOW, In, degrees K. Add words to exlist to ignore them.
# Also find lines of the type: '(a) .*' and surround them with '\wrongchoice{ (a) .*}'

import re, sys

if len(sys.argv) < 2 :
  print('Usage:> {} <filename>'.format(sys.argv[0]))
  sys.exit(1)

ptable =" H                                                                  He "
ptable+=" Li  Be                                         B   C   N   O   F   Ne "
ptable+=" Na  Mg                                         Al  Si  P   S   Cl  Ar "
ptable+=" K   Ca  Sc  Ti  V   Cr  Mn  Fe  Co  Ni  Cu  Zn Ga  Ge  As  Se  Br  Kr "
ptable+=" Rb  Sr  Y   Zr  Nb  Mo  Tc  Ru  Rh  Pd  Ag  Cd In  Sn  Sb  Te  I   Xe "
ptable+=" Cs  Ba  La  Hf  Ta  W   Re  Os  Ir  Pt  Au  Hg Tl  Pb  Bi  Po  At  Rn "
ptable+=" Fr  Ra  Ac  Rf  Db  Sg  Bh  Hs  Mt  Ds  Rg  Cn Nh  Fl  Mc  Lv  Ts  Og "
ptable+="             Ce  Pr  Nd  Pm  Sm  Eu  Gd  Tb  Dy Ho  Er  Tm  Yb  Lu     "
ptable+="             Th  Pa  U   Np  Pu  Am  Cm  Bk  Cf Es  Fm  Md  No  Lr     "

exlist = ['C','I','In','K','HOW'] # exclude these words from being replaced
orsyms = '|'.join(ptable.split())
resyms = re.compile(r'\b'+'((?:(?:{})\d*)+)'.format(orsyms)+r'\b')
rewrng = re.compile(r'^\s*\([a-d]\).*')

latexfile=sys.argv[1]
with open(latexfile,'r') as fd:
    for line in fd:

        for m in list(set(resyms.findall(line))):
            if m not in exlist :
                line = re.sub(r'\b'+m+r'\b', r'\ce{'+m+r'}', line)

        if rewrng.match(line) :
            line = r'\wrongchoice{ '+line[:-1:]+r'}'+'\n'

        print(line,end='')