[regex] Regular expression to match numbers with or without commas and decimals in text

Some days ago, I worked on the problem of removing trailing zeros from the string of a number.

In the continuity of that problem, I find this one interesting because it widens the problem to numbers comprising commas.

I have taken the regex's pattern I had writen in that previous problem I worked on and I improved it in order that it can treat the numbers with commas as an answer for this problem.

I've been carried away with my enthusiasm and my liking of regexes. I don't know if the result fits exactly to the need expressed by Michael Prescott. I would be interested to know the points that are in excess or in lack in my regex, and to correct it to make it more suitable for you.

Now, after a long session of work on this regex, I have a sort of weight in the brain, so I'm not fresh enough to give a lot of explanation. If points are obscure, and if anybody may come to be interested enough, please, ask me.

The regex is built in order that it can detect the numbers expressed in scientific notation 2E10 or even 5,22,454.12E-00.0478 , removing unnecessary zeros in the two parts of such numbers too. If an exponent is equal to zero , the number is modified so that there is no more exponent.

I put some verification in the pattern so that some particular cases will not match, for exemple '12..57' won't match. But in ',111' the string '111' matches because the preceding comma is considered a comma not being in a number but a comma of sentence.

I think that the managing of commas should be improved, because it seems to me that there are only 2 digits between commas in Indian numbering. It won't be dificult to correct, I presume

Here after is a code demonstrating how my regex works. There are two functions, according if one wants the numbers '.1245' to be transformed in '0.1245' or not. I wouldn't be surprised if errors or unwanted matchings or unmatchings will remain for certain cases of number strings; then I'd like to know these cases to understand and correct the deficiency.

I apologize for this code written in Python, but regexes are trans-langage and I think everybody will be capable of undertsanding the reex's pattern

import re

regx = re.compile('(?<![\d.])(?!\.\.)(?<![\d.][eE][+-])(?<![\d.][eE])(?<!\d[.,])'
                  '' #---------------------------------
                  '([+-]?)'
                  '(?![\d,]*?\.[\d,]*?\.[\d,]*?)'
                  '(?:0|,(?=0)|(?<!\d),)*'
                  '(?:'
                  '((?:\d(?!\.[1-9])|,(?=\d))+)[.,]?'
                  '|\.(0)'
                  '|((?<!\.)\.\d+?)'
                  '|([\d,]+\.\d+?))'
                  '0*'
                  '' #---------------------------------
                  '(?:'
                  '([eE][+-]?)(?:0|,(?=0))*'
                  '(?:'
                  '(?!0+(?=\D|\Z))((?:\d(?!\.[1-9])|,(?=\d))+)[.,]?'
                  '|((?<!\.)\.(?!0+(?=\D|\Z))\d+?)'
                  '|([\d,]+\.(?!0+(?=\D|\Z))\d+?))'
                  '0*'
                  ')?'
                  '' #---------------------------------
                  '(?![.,]?\d)')


def dzs_numbs(x,regx = regx): # ds = detect and zeros-shave
    if not regx.findall(x):
        yield ('No match,', 'No catched string,', 'No groups.')
    for mat in regx.finditer(x):
        yield (mat.group(), ''.join(mat.groups('')), mat.groups(''))

def dzs_numbs2(x,regx = regx): # ds = detect and zeros-shave
    if not regx.findall(x):
        yield ('No match,', 'No catched string,', 'No groups.')
    for mat in regx.finditer(x):
        yield (mat.group(),
               ''.join(('0' if n.startswith('.') else '')+n for n in mat.groups('')),
               mat.groups(''))

NS = ['  23456000and23456000. or23456000.000  00023456000 s000023456000.  000023456000.000 ',
      'arf 10000 sea10000.+10000.000  00010000-00010000. kant00010000.000 ',
      '  24:  24,  24.   24.000  24.000,   00024r 00024. blue 00024.000  ',
      '  8zoom8.  8.000  0008  0008. and0008.000  ',
      '  0   00000M0. = 000.  0.0  0.000    000.0   000.000   .000000   .0   ',
      '  .0000023456    .0000023456000   '
      '  .0005872    .0005872000   .00503   .00503000   ',
      '  .068    .0680000   .8   .8000  .123456123456    .123456123456000    ',
      '  .657   .657000   .45    .4500000   .7    .70000  0.0000023230000   000.0000023230000   ',
      '  0.0081000    0000.0081000  0.059000   0000.059000     ',
      '  0.78987400000 snow  00000.78987400000  0.4400000   00000.4400000   ',
      '  -0.5000  -0000.5000   0.90   000.90   0.7   000.7   ',
      '  2.6    00002.6   00002.60000  4.71   0004.71    0004.7100   ',
      '  23.49   00023.49   00023.490000  103.45   0000103.45   0000103.45000    ',
      '  10003.45067   000010003.45067   000010003.4506700 ',
      '  +15000.0012   +000015000.0012   +000015000.0012000    ',
      '  78000.89   000078000.89   000078000.89000    ',
      '  .0457e10   .0457000e10   00000.0457000e10  ',
      '   258e8   2580000e4   0000000002580000e4   ',
      '  0.782e10   0000.782e10   0000.7820000e10  ',
      '  1.23E2   0001.23E2  0001.2300000E2   ',
      '  432e-102  0000432e-102   004320000e-106   ',
      '  1.46e10and0001.46e10  0001.4600000e10   ',
      '  1.077e-300  0001.077e-300  0001.077000e-300   ',
      '  1.069e10   0001.069e10   0001.069000e10   ',
      '  105040.03e10  000105040.03e10  105040.0300e10    ',
      '  +286E000024.487900  -78.4500e.14500   .0140E789.  ',
      '  081,12.40E07,95.0120     0045,78,123.03500e-0.00  ',
      '  0096,78,473.0380e-0.    0008,78,373.066000E0.    0004512300.E0000  ',
      '  ..18000  25..00 36...77   2..8  ',
      '  3.8..9    .12500.     12.51.400  ',
      '  00099,111.8713000   -0012,45,83,987.26+0.000,099,88,44.or00,00,00.00must',
      '  00099,44,and   0000,099,88,44.bom',
      '00,000,00.587000  77,98,23,45.,  this,that ',
      '  ,111  145.20  +9,9,9  0012800  .,,.  1  100,000 ',
      '1,1,1.111  000,001.111   -999.  0.  111.110000  1.1.1.111  9.909,888']


for ch in NS:
    print 'string: '+repr(ch)
    for strmatch, modified, the_groups in dzs_numbs2(ch):
        print strmatch.rjust(20),'',modified,'',the_groups
    print

result

string: '  23456000and23456000. or23456000.000  00023456000 s000023456000.  000023456000.000 '
            23456000  23456000  ('', '23456000', '', '', '', '', '', '', '')
           23456000.  23456000  ('', '23456000', '', '', '', '', '', '', '')
        23456000.000  23456000  ('', '23456000', '', '', '', '', '', '', '')
         00023456000  23456000  ('', '23456000', '', '', '', '', '', '', '')
       000023456000.  23456000  ('', '23456000', '', '', '', '', '', '', '')
    000023456000.000  23456000  ('', '23456000', '', '', '', '', '', '', '')

string: 'arf 10000 sea10000.+10000.000  00010000-00010000. kant00010000.000 '
               10000  10000  ('', '10000', '', '', '', '', '', '', '')
              10000.  10000  ('', '10000', '', '', '', '', '', '', '')
           10000.000  10000  ('', '10000', '', '', '', '', '', '', '')
            00010000  10000  ('', '10000', '', '', '', '', '', '', '')
           00010000.  10000  ('', '10000', '', '', '', '', '', '', '')
        00010000.000  10000  ('', '10000', '', '', '', '', '', '', '')

string: '  24:  24,  24.   24.000  24.000,   00024r 00024. blue 00024.000  '
                  24  24  ('', '24', '', '', '', '', '', '', '')
                 24,  24  ('', '24', '', '', '', '', '', '', '')
                 24.  24  ('', '24', '', '', '', '', '', '', '')
              24.000  24  ('', '24', '', '', '', '', '', '', '')
              24.000  24  ('', '24', '', '', '', '', '', '', '')
               00024  24  ('', '24', '', '', '', '', '', '', '')
              00024.  24  ('', '24', '', '', '', '', '', '', '')
           00024.000  24  ('', '24', '', '', '', '', '', '', '')

string: '  8zoom8.  8.000  0008  0008. and0008.000  '
                   8  8  ('', '8', '', '', '', '', '', '', '')
                  8.  8  ('', '8', '', '', '', '', '', '', '')
               8.000  8  ('', '8', '', '', '', '', '', '', '')
                0008  8  ('', '8', '', '', '', '', '', '', '')
               0008.  8  ('', '8', '', '', '', '', '', '', '')
            0008.000  8  ('', '8', '', '', '', '', '', '', '')

string: '  0   00000M0. = 000.  0.0  0.000    000.0   000.000   .000000   .0   '
                   0  0  ('', '0', '', '', '', '', '', '', '')
               00000  0  ('', '0', '', '', '', '', '', '', '')
                  0.  0  ('', '0', '', '', '', '', '', '', '')
                000.  0  ('', '0', '', '', '', '', '', '', '')
                 0.0  0  ('', '', '0', '', '', '', '', '', '')
               0.000  0  ('', '', '0', '', '', '', '', '', '')
               000.0  0  ('', '', '0', '', '', '', '', '', '')
             000.000  0  ('', '', '0', '', '', '', '', '', '')
             .000000  0  ('', '', '0', '', '', '', '', '', '')
                  .0  0  ('', '', '0', '', '', '', '', '', '')

string: '  .0000023456    .0000023456000     .0005872    .0005872000   .00503   .00503000   '
         .0000023456  0.0000023456  ('', '', '', '.0000023456', '', '', '', '', '')
      .0000023456000  0.0000023456  ('', '', '', '.0000023456', '', '', '', '', '')
            .0005872  0.0005872  ('', '', '', '.0005872', '', '', '', '', '')
         .0005872000  0.0005872  ('', '', '', '.0005872', '', '', '', '', '')
              .00503  0.00503  ('', '', '', '.00503', '', '', '', '', '')
           .00503000  0.00503  ('', '', '', '.00503', '', '', '', '', '')

string: '  .068    .0680000   .8   .8000  .123456123456    .123456123456000    '
                .068  0.068  ('', '', '', '.068', '', '', '', '', '')
            .0680000  0.068  ('', '', '', '.068', '', '', '', '', '')
                  .8  0.8  ('', '', '', '.8', '', '', '', '', '')
               .8000  0.8  ('', '', '', '.8', '', '', '', '', '')
       .123456123456  0.123456123456  ('', '', '', '.123456123456', '', '', '', '', '')
    .123456123456000  0.123456123456  ('', '', '', '.123456123456', '', '', '', '', '')

string: '  .657   .657000   .45    .4500000   .7    .70000  0.0000023230000   000.0000023230000   '
                .657  0.657  ('', '', '', '.657', '', '', '', '', '')
             .657000  0.657  ('', '', '', '.657', '', '', '', '', '')
                 .45  0.45  ('', '', '', '.45', '', '', '', '', '')
            .4500000  0.45  ('', '', '', '.45', '', '', '', '', '')
                  .7  0.7  ('', '', '', '.7', '', '', '', '', '')
              .70000  0.7  ('', '', '', '.7', '', '', '', '', '')
     0.0000023230000  0.000002323  ('', '', '', '.000002323', '', '', '', '', '')
   000.0000023230000  0.000002323  ('', '', '', '.000002323', '', '', '', '', '')

string: '  0.0081000    0000.0081000  0.059000   0000.059000     '
           0.0081000  0.0081  ('', '', '', '.0081', '', '', '', '', '')
        0000.0081000  0.0081  ('', '', '', '.0081', '', '', '', '', '')
            0.059000  0.059  ('', '', '', '.059', '', '', '', '', '')
         0000.059000  0.059  ('', '', '', '.059', '', '', '', '', '')

string: '  0.78987400000 snow  00000.78987400000  0.4400000   00000.4400000   '
       0.78987400000  0.789874  ('', '', '', '.789874', '', '', '', '', '')
   00000.78987400000  0.789874  ('', '', '', '.789874', '', '', '', '', '')
           0.4400000  0.44  ('', '', '', '.44', '', '', '', '', '')
       00000.4400000  0.44  ('', '', '', '.44', '', '', '', '', '')

string: '  -0.5000  -0000.5000   0.90   000.90   0.7   000.7   '
             -0.5000  -0.5  ('-', '', '', '.5', '', '', '', '', '')
          -0000.5000  -0.5  ('-', '', '', '.5', '', '', '', '', '')
                0.90  0.9  ('', '', '', '.9', '', '', '', '', '')
              000.90  0.9  ('', '', '', '.9', '', '', '', '', '')
                 0.7  0.7  ('', '', '', '.7', '', '', '', '', '')
               000.7  0.7  ('', '', '', '.7', '', '', '', '', '')

string: '  2.6    00002.6   00002.60000  4.71   0004.71    0004.7100   '
                 2.6  2.6  ('', '', '', '', '2.6', '', '', '', '')
             00002.6  2.6  ('', '', '', '', '2.6', '', '', '', '')
         00002.60000  2.6  ('', '', '', '', '2.6', '', '', '', '')
                4.71  4.71  ('', '', '', '', '4.71', '', '', '', '')
             0004.71  4.71  ('', '', '', '', '4.71', '', '', '', '')
           0004.7100  4.71  ('', '', '', '', '4.71', '', '', '', '')

string: '  23.49   00023.49   00023.490000  103.45   0000103.45   0000103.45000    '
               23.49  23.49  ('', '', '', '', '23.49', '', '', '', '')
            00023.49  23.49  ('', '', '', '', '23.49', '', '', '', '')
        00023.490000  23.49  ('', '', '', '', '23.49', '', '', '', '')
              103.45  103.45  ('', '', '', '', '103.45', '', '', '', '')
          0000103.45  103.45  ('', '', '', '', '103.45', '', '', '', '')
       0000103.45000  103.45  ('', '', '', '', '103.45', '', '', '', '')

string: '  10003.45067   000010003.45067   000010003.4506700 '
         10003.45067  10003.45067  ('', '', '', '', '10003.45067', '', '', '', '')
     000010003.45067  10003.45067  ('', '', '', '', '10003.45067', '', '', '', '')
   000010003.4506700  10003.45067  ('', '', '', '', '10003.45067', '', '', '', '')

string: '  +15000.0012   +000015000.0012   +000015000.0012000    '
         +15000.0012  +15000.0012  ('+', '', '', '', '15000.0012', '', '', '', '')
     +000015000.0012  +15000.0012  ('+', '', '', '', '15000.0012', '', '', '', '')
  +000015000.0012000  +15000.0012  ('+', '', '', '', '15000.0012', '', '', '', '')

string: '  78000.89   000078000.89   000078000.89000    '
            78000.89  78000.89  ('', '', '', '', '78000.89', '', '', '', '')
        000078000.89  78000.89  ('', '', '', '', '78000.89', '', '', '', '')
     000078000.89000  78000.89  ('', '', '', '', '78000.89', '', '', '', '')

string: '  .0457e10   .0457000e10   00000.0457000e10  '
            .0457e10  0.0457e10  ('', '', '', '.0457', '', 'e', '10', '', '')
         .0457000e10  0.0457e10  ('', '', '', '.0457', '', 'e', '10', '', '')
    00000.0457000e10  0.0457e10  ('', '', '', '.0457', '', 'e', '10', '', '')

string: '   258e8   2580000e4   0000000002580000e4   '
               258e8  258e8  ('', '258', '', '', '', 'e', '8', '', '')
           2580000e4  2580000e4  ('', '2580000', '', '', '', 'e', '4', '', '')
  0000000002580000e4  2580000e4  ('', '2580000', '', '', '', 'e', '4', '', '')

string: '  0.782e10   0000.782e10   0000.7820000e10  '
            0.782e10  0.782e10  ('', '', '', '.782', '', 'e', '10', '', '')
         0000.782e10  0.782e10  ('', '', '', '.782', '', 'e', '10', '', '')
     0000.7820000e10  0.782e10  ('', '', '', '.782', '', 'e', '10', '', '')

string: '  1.23E2   0001.23E2  0001.2300000E2   '
              1.23E2  1.23E2  ('', '', '', '', '1.23', 'E', '2', '', '')
           0001.23E2  1.23E2  ('', '', '', '', '1.23', 'E', '2', '', '')
      0001.2300000E2  1.23E2  ('', '', '', '', '1.23', 'E', '2', '', '')

string: '  432e-102  0000432e-102   004320000e-106   '
            432e-102  432e-102  ('', '432', '', '', '', 'e-', '102', '', '')
        0000432e-102  432e-102  ('', '432', '', '', '', 'e-', '102', '', '')
      004320000e-106  4320000e-106  ('', '4320000', '', '', '', 'e-', '106', '', '')

string: '  1.46e10and0001.46e10  0001.4600000e10   '
             1.46e10  1.46e10  ('', '', '', '', '1.46', 'e', '10', '', '')
          0001.46e10  1.46e10  ('', '', '', '', '1.46', 'e', '10', '', '')
     0001.4600000e10  1.46e10  ('', '', '', '', '1.46', 'e', '10', '', '')

string: '  1.077e-300  0001.077e-300  0001.077000e-300   '
          1.077e-300  1.077e-300  ('', '', '', '', '1.077', 'e-', '300', '', '')
       0001.077e-300  1.077e-300  ('', '', '', '', '1.077', 'e-', '300', '', '')
    0001.077000e-300  1.077e-300  ('', '', '', '', '1.077', 'e-', '300', '', '')

string: '  1.069e10   0001.069e10   0001.069000e10   '
            1.069e10  1.069e10  ('', '', '', '', '1.069', 'e', '10', '', '')
         0001.069e10  1.069e10  ('', '', '', '', '1.069', 'e', '10', '', '')
      0001.069000e10  1.069e10  ('', '', '', '', '1.069', 'e', '10', '', '')

string: '  105040.03e10  000105040.03e10  105040.0300e10    '
        105040.03e10  105040.03e10  ('', '', '', '', '105040.03', 'e', '10', '', '')
     000105040.03e10  105040.03e10  ('', '', '', '', '105040.03', 'e', '10', '', '')
      105040.0300e10  105040.03e10  ('', '', '', '', '105040.03', 'e', '10', '', '')

string: '  +286E000024.487900  -78.4500e.14500   .0140E789.  '
  +286E000024.487900  +286E24.4879  ('+', '286', '', '', '', 'E', '', '', '24.4879')
     -78.4500e.14500  -78.45e0.145  ('-', '', '', '', '78.45', 'e', '', '.145', '')
          .0140E789.  0.014E789  ('', '', '', '.014', '', 'E', '789', '', '')

string: '  081,12.40E07,95.0120     0045,78,123.03500e-0.00  '
081,12.40E07,95.0120  81,12.4E7,95.012  ('', '', '', '', '81,12.4', 'E', '', '', '7,95.012')
   0045,78,123.03500  45,78,123.035  ('', '', '', '', '45,78,123.035', '', '', '', '')

string: '  0096,78,473.0380e-0.    0008,78,373.066000E0.    0004512300.E0000  '
    0096,78,473.0380  96,78,473.038  ('', '', '', '', '96,78,473.038', '', '', '', '')
  0008,78,373.066000  8,78,373.066  ('', '', '', '', '8,78,373.066', '', '', '', '')
         0004512300.  4512300  ('', '4512300', '', '', '', '', '', '', '')

string: '  ..18000  25..00 36...77   2..8  '
           No match,  No catched string,  No groups.

string: '  3.8..9    .12500.     12.51.400  '
           No match,  No catched string,  No groups.

string: '  00099,111.8713000   -0012,45,83,987.26+0.000,099,88,44.or00,00,00.00must'
   00099,111.8713000  99,111.8713  ('', '', '', '', '99,111.8713', '', '', '', '')
  -0012,45,83,987.26  -12,45,83,987.26  ('-', '', '', '', '12,45,83,987.26', '', '', '', '')
         00,00,00.00  0  ('', '', '0', '', '', '', '', '', '')

string: '  00099,44,and   0000,099,88,44.bom'
           00099,44,  99,44  ('', '99,44', '', '', '', '', '', '', '')
     0000,099,88,44.  99,88,44  ('', '99,88,44', '', '', '', '', '', '', '')

string: '00,000,00.587000  77,98,23,45.,  this,that '
    00,000,00.587000  0.587  ('', '', '', '.587', '', '', '', '', '')
        77,98,23,45.  77,98,23,45  ('', '77,98,23,45', '', '', '', '', '', '', '')

string: '  ,111  145.20  +9,9,9  0012800  .,,.  1  100,000 '
                ,111  111  ('', '111', '', '', '', '', '', '', '')
              145.20  145.2  ('', '', '', '', '145.2', '', '', '', '')
              +9,9,9  +9,9,9  ('+', '9,9,9', '', '', '', '', '', '', '')
             0012800  12800  ('', '12800', '', '', '', '', '', '', '')
                   1  1  ('', '1', '', '', '', '', '', '', '')
             100,000  100,000  ('', '100,000', '', '', '', '', '', '', '')

string: '1,1,1.111  000,001.111   -999.  0.  111.110000  1.1.1.111  9.909,888'
           1,1,1.111  1,1,1.111  ('', '', '', '', '1,1,1.111', '', '', '', '')
         000,001.111  1.111  ('', '', '', '', '1.111', '', '', '', '')
               -999.  -999  ('-', '999', '', '', '', '', '', '', '')
                  0.  0  ('', '0', '', '', '', '', '', '', '')
          111.110000  111.11  ('', '', '', '', '111.11', '', '', '', '')