import re
s = "python java php c"
regex = re.compile('[a-zA-Z0-9]')
regex_find = regex.finditer(s)
idx_positions = {}
frequency = {}
for matchs in regex_find:
print('*', matchs)
frequency[matchs.group()] = frequency.get(matchs.group(), 0) + 1
print('**', frequency.get(matchs.group(), 0) + 1)
idx_positions[matchs.group()] = idx_positions.get(matchs.group(), []) + [matchs.start()]
print('***', idx_positions.get(matchs.group(), []) + [matchs.start()])
print('****', idx_positions)
for (key, value) in frequency.items():
print(key , " frequency : ", value , ' indexes : ', idx_positions[key])
'''
run:
* <re.Match object; span=(0, 1), match='p'>
** 2
*** [0, 0]
**** {'p': [0]}
* <re.Match object; span=(1, 2), match='y'>
** 2
*** [1, 1]
**** {'p': [0], 'y': [1]}
* <re.Match object; span=(2, 3), match='t'>
** 2
*** [2, 2]
**** {'p': [0], 'y': [1], 't': [2]}
* <re.Match object; span=(3, 4), match='h'>
** 2
*** [3, 3]
**** {'p': [0], 'y': [1], 't': [2], 'h': [3]}
* <re.Match object; span=(4, 5), match='o'>
** 2
*** [4, 4]
**** {'p': [0], 'y': [1], 't': [2], 'h': [3], 'o': [4]}
* <re.Match object; span=(5, 6), match='n'>
** 2
*** [5, 5]
**** {'p': [0], 'y': [1], 't': [2], 'h': [3], 'o': [4], 'n': [5]}
* <re.Match object; span=(7, 8), match='j'>
** 2
*** [7, 7]
**** {'p': [0], 'y': [1], 't': [2], 'h': [3], 'o': [4], 'n': [5], 'j': [7]}
* <re.Match object; span=(8, 9), match='a'>
** 2
*** [8, 8]
**** {'p': [0], 'y': [1], 't': [2], 'h': [3], 'o': [4], 'n': [5], 'j': [7], 'a': [8]}
* <re.Match object; span=(9, 10), match='v'>
** 2
*** [9, 9]
**** {'p': [0], 'y': [1], 't': [2], 'h': [3], 'o': [4], 'n': [5], 'j': [7], 'a': [8], 'v': [9]}
* <re.Match object; span=(10, 11), match='a'>
** 3
*** [8, 10, 10]
**** {'p': [0], 'y': [1], 't': [2], 'h': [3], 'o': [4], 'n': [5], 'j': [7], 'a': [8, 10], 'v': [9]}
* <re.Match object; span=(12, 13), match='p'>
** 3
*** [0, 12, 12]
**** {'p': [0, 12], 'y': [1], 't': [2], 'h': [3], 'o': [4], 'n': [5], 'j': [7], 'a': [8, 10], 'v': [9]}
* <re.Match object; span=(13, 14), match='h'>
** 3
*** [3, 13, 13]
**** {'p': [0, 12], 'y': [1], 't': [2], 'h': [3, 13], 'o': [4], 'n': [5], 'j': [7], 'a': [8, 10], 'v': [9]}
* <re.Match object; span=(14, 15), match='p'>
** 4
*** [0, 12, 14, 14]
**** {'p': [0, 12, 14], 'y': [1], 't': [2], 'h': [3, 13], 'o': [4], 'n': [5], 'j': [7], 'a': [8,10], 'v': [9]}
* <re.Match object; span=(16, 17), match='c'>
** 2
*** [16, 16]
**** {'p': [0, 12, 14], 'y': [1], 't': [2], 'h': [3, 13], 'o': [4], 'n': [5], 'j': [7], 'a': [8,10], 'v': [9], 'c': [16]}
p frequency : 3 indexes : [0, 12, 14]
y frequency : 1 indexes : [1]
t frequency : 1 indexes : [2]
h frequency : 2 indexes : [3, 13]
o frequency : 1 indexes : [4]
n frequency : 1 indexes : [5]
j frequency : 1 indexes : [7]
a frequency : 2 indexes : [8, 10]
v frequency : 1 indexes : [9]
c frequency : 1 indexes : [16]
'''
