Parsing of a file

[Bruno Desthuilliers]

Tommy Grav a écrit :
> I have a file with the format
> 
> Field f29227: Ra=20:23:46.54 Dec=+67:30:00.0 MJD=53370.06797690 Frames 5 
> Set 1
> Field f31448: Ra=20:24:58.13 Dec=+79:39:43.9 MJD=53370.06811620 Frames 5 
> Set 2
> Field f31226: Ra=20:24:45.50 Dec=+78:26:45.2 MJD=53370.06823860 Frames 5 
> Set 3
> Field f31004: Ra=20:25:05.28 Dec=+77:13:46.9 MJD=53370.06836020 Frames 5 
> Set 4
> Field f30782: Ra=20:25:51.94 Dec=+76:00:48.6 MJD=53370.06848210 Frames 5 
> Set 5
> Field f30560: Ra=20:27:01.82 Dec=+74:47:50.3 MJD=53370.06860400 Frames 5 
> Set 6
> Field f30338: Ra=20:28:32.35 Dec=+73:34:52.0 MJD=53370.06872620 Frames 5 
> Set 7
> Field f30116: Ra=20:30:21.70 Dec=+72:21:53.6 MJD=53370.06884890 Frames 5 
> Set 8
> Field f29894: Ra=20:32:28.54 Dec=+71:08:55.0 MJD=53370.06897070 Frames 5 
> Set 9
> Field f29672: Ra=20:34:51.89 Dec=+69:55:56.6 MJD=53370.06909350 Frames 5 
> Set 10
> 
> I would like to parse this file by extracting the field id, ra, dec and 
> mjd for each line. It is
> not, however, certain that the width of each value of the field id, ra, 
> dec or mjd is the same
> in each line. Is there a way to do this such that even if there was a 
> line where Ra=****** and
> MJD=******** was swapped it would be parsed correctly?

Q&D :

src = open('/path/to/yourfile.ext')
parsed = []
for line in src:
     line = line.strip()
     if not line:
         continue
     head, rest = line.split(':', 1)
     field_id = head.split()[1]
     data = dict(field_id=field_id)
     parts = rest.split()
     for part in parts:
         try:
             key, val = part.split('=')
         except ValueError:
             continue
         data[key] = val
     parsed.append(data)
src.close()