Esempio n. 1
0
def _simple_parser(lines, colNames=None, header=0, index_col=0,
                   na_values=None, date_parser=None, parse_dates=True):
    """
    Workhorse function for processing nested list into DataFrame

    Should be replaced by np.genfromtxt eventually?
    """
    if header is not None:
        columns = []
        for i, c in enumerate(lines[header]):
            if c == '':
                columns.append('Unnamed: %d' % i)
            else:
                columns.append(c)

        content = lines[header+1:]

        counts = {}
        for i, col in enumerate(columns):
            cur_count = counts.get(col, 0)
            if cur_count > 0:
                columns[i] = '%s.%d' % (col, cur_count)
            counts[col] = cur_count + 1
    else:
        ncols = len(lines[0])
        if not colNames:
            columns = ['X.%d' % (i + 1) for i in range(ncols)]
        else:
            assert(len(colNames) == ncols)
            columns = colNames
        content = lines

    if len(content) == 0: # pragma: no cover
        if index_col is not None:
            if np.isscalar(index_col):
                index = Index([], name=columns.pop(index_col))
            else:
                cp_cols = list(columns)
                names = []
                for i in index_col:
                    name = cp_cols[i]
                    columns.remove(name)
                    names.append(name)
                index = MultiIndex.fromarrays([[]] * len(index_col),
                                              names=names)
        else:
            index = Index([])

        return DataFrame(index=index, columns=columns)


    # common NA values
    # no longer excluding inf representations
    # '1.#INF','-1.#INF', '1.#INF000000',
    NA_VALUES = set(['-1.#IND', '1.#QNAN', '1.#IND', '-1.#QNAN',
                     '#N/A N/A', 'NA', '#NA', 'NULL', 'NaN',
                     'nan', ''])
    if na_values is None:
        na_values = NA_VALUES
    else:
        na_values = set(list(na_values)) | NA_VALUES


    zipped_content = list(lib.to_object_array(content).T)

    if index_col is None and len(content[0]) == len(columns) + 1:
        index_col = 0

    # no index column specified, so infer that's what is wanted
    if index_col is not None:
        if np.isscalar(index_col):
            index = zipped_content.pop(index_col)

            if len(content[0]) == len(columns) + 1:
                name = None
            else:
                name = columns.pop(index_col)

        else: # given a list of index
            idx_names = []
            index = []
            for idx in index_col:
                idx_names.append(columns[idx])
                index.append(zipped_content[idx])
            #remove index items from content and columns, don't pop in loop
            for i in range(len(index_col)):
                columns.remove(idx_names[i])
                zipped_content.remove(index[i])

        if np.isscalar(index_col):
            if parse_dates:
                index = lib.try_parse_dates(index, parser=date_parser)
            index = Index(_convert_types(index, na_values), name=name)
        else:
            arrays = _maybe_convert_int_mindex(index, parse_dates,
                                               date_parser)
            index = MultiIndex.from_arrays(arrays,
                                                 names=idx_names)
    else:
        index = Index(np.arange(len(content)))

    if not index._verify_integrity():
        dups = index._get_duplicates()
        raise Exception('Index has duplicates: %s' % str(dups))

    if len(columns) != len(zipped_content):
        raise Exception('wrong number of columns')

    data = dict((k, v) for k, v in zip(columns, zipped_content))
    data = _convert_to_ndarrays(data, na_values)
    return DataFrame(data=data, columns=columns, index=index)