In a file there can be several dictionaries like this {Key11: Value11 Key12: Value12 Key13: Value13, ... ... Key1n:Value1n} {Key21: Value21 Key22: Value22 Key23: Value23, ... ... Key2n:Value2n} {Key31: Value31 Key32: Value32 Key33: Value33, ... ... Key3n:Value3n} .... .... .... {Keyn1: Valuen1 Keyn2: Valuen2 Keyn3: Value3, ... ... Keynn:Valuenn}
Each pair in a dictionary is separated by CRLF and in each dictionary numbers of pairs can be different. I need to read only the the first and the last dictionaries.What is a best solution?
Assumption:
File is small enough to be read into memory at once. Contents of the file have been read into the variable "testdata":
py> # your data
py> testdata="""
... {Key11: Value11
... Key12: Value12,
... Key13: Value13}
... {Key21: Value21,
... Key22: Value22
... Key23: Value23}
... {Key31: Value31
... Key32: Value32,
... Key33: Value33}
... """
py>
py> # get the contents of the first and last dict
py> content_strs = testdata.strip('{}\n\t ').split('}\n{')
py> content_strs = content_strs[0], content_strs[1]
py> print content_strs
('Key11: Value11\nKey12: Value12,\nKey13: Value13', 'Key21: Value21,\nKey22: Value22\nKey23: Value23')
py>
py> # correct missing commas and add braces
py> dict_strs = ['{%s}' % s.replace('\n', ',\n').replace(',,\n', ',\n')
... for s in content_strs]
py> print dict_strs
['{Key11: Value11,\nKey12: Value12,\nKey13: Value13}', '{Key21: Value21,\nKey22: Value22,\nKey23: Value23}']
py>
py> # build mapping of names to values
py> names = {}
py> for i in range(1, 4):
... for j in range(1, 4):
... s = '%i%i' % (i, j)
... names['Key%s' % s] = int(s)
... names['Value%s' % s] = 'V%s' % s
...
py>
py> # eval strings to get dicts
py> first_dict, last_dict = [eval(s, names) for s in dict_strs]
py> first_dict
{11: 'V11', 12: 'V12', 13: 'V13'}
py> last_dict
{21: 'V21', 22: 'V22', 23: 'V23'}
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