8th day of python challenges 111-117

venv/lib/python3.6/site-packages/pandas/io/excel/_util.py

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+import warnings
+
+from pandas.compat._optional import import_optional_dependency
+
+from pandas.core.dtypes.common import is_integer, is_list_like
+
+_writers = {}
+
+
+def register_writer(klass):
+    """
+    Add engine to the excel writer registry.io.excel.
+
+    You must use this method to integrate with ``to_excel``.
+
+    Parameters
+    ----------
+    klass : ExcelWriter
+    """
+    if not callable(klass):
+        raise ValueError("Can only register callables as engines")
+    engine_name = klass.engine
+    _writers[engine_name] = klass
+
+
+def _get_default_writer(ext):
+    """
+    Return the default writer for the given extension.
+
+    Parameters
+    ----------
+    ext : str
+        The excel file extension for which to get the default engine.
+
+    Returns
+    -------
+    str
+        The default engine for the extension.
+    """
+    _default_writers = {"xlsx": "openpyxl", "xlsm": "openpyxl", "xls": "xlwt"}
+    xlsxwriter = import_optional_dependency(
+        "xlsxwriter", raise_on_missing=False, on_version="warn"
+    )
+    if xlsxwriter:
+        _default_writers["xlsx"] = "xlsxwriter"
+    return _default_writers[ext]
+
+
+def get_writer(engine_name):
+    try:
+        return _writers[engine_name]
+    except KeyError:
+        raise ValueError("No Excel writer '{engine}'".format(engine=engine_name))
+
+
+def _excel2num(x):
+    """
+    Convert Excel column name like 'AB' to 0-based column index.
+
+    Parameters
+    ----------
+    x : str
+        The Excel column name to convert to a 0-based column index.
+
+    Returns
+    -------
+    num : int
+        The column index corresponding to the name.
+
+    Raises
+    ------
+    ValueError
+        Part of the Excel column name was invalid.
+    """
+    index = 0
+
+    for c in x.upper().strip():
+        cp = ord(c)
+
+        if cp < ord("A") or cp > ord("Z"):
+            raise ValueError("Invalid column name: {x}".format(x=x))
+
+        index = index * 26 + cp - ord("A") + 1
+
+    return index - 1
+
+
+def _range2cols(areas):
+    """
+    Convert comma separated list of column names and ranges to indices.
+
+    Parameters
+    ----------
+    areas : str
+        A string containing a sequence of column ranges (or areas).
+
+    Returns
+    -------
+    cols : list
+        A list of 0-based column indices.
+
+    Examples
+    --------
+    >>> _range2cols('A:E')
+    [0, 1, 2, 3, 4]
+    >>> _range2cols('A,C,Z:AB')
+    [0, 2, 25, 26, 27]
+    """
+    cols = []
+
+    for rng in areas.split(","):
+        if ":" in rng:
+            rng = rng.split(":")
+            cols.extend(range(_excel2num(rng[0]), _excel2num(rng[1]) + 1))
+        else:
+            cols.append(_excel2num(rng))
+
+    return cols
+
+
+def _maybe_convert_usecols(usecols):
+    """
+    Convert `usecols` into a compatible format for parsing in `parsers.py`.
+
+    Parameters
+    ----------
+    usecols : object
+        The use-columns object to potentially convert.
+
+    Returns
+    -------
+    converted : object
+        The compatible format of `usecols`.
+    """
+    if usecols is None:
+        return usecols
+
+    if is_integer(usecols):
+        warnings.warn(
+            (
+                "Passing in an integer for `usecols` has been "
+                "deprecated. Please pass in a list of int from "
+                "0 to `usecols` inclusive instead."
+            ),
+            FutureWarning,
+            stacklevel=2,
+        )
+        return list(range(usecols + 1))
+
+    if isinstance(usecols, str):
+        return _range2cols(usecols)
+
+    return usecols
+
+
+def _validate_freeze_panes(freeze_panes):
+    if freeze_panes is not None:
+        if len(freeze_panes) == 2 and all(
+            isinstance(item, int) for item in freeze_panes
+        ):
+            return True
+
+        raise ValueError(
+            "freeze_panes must be of form (row, column)"
+            " where row and column are integers"
+        )
+
+    # freeze_panes wasn't specified, return False so it won't be applied
+    # to output sheet
+    return False
+
+
+def _trim_excel_header(row):
+    # trim header row so auto-index inference works
+    # xlrd uses '' , openpyxl None
+    while len(row) > 0 and (row[0] == "" or row[0] is None):
+        row = row[1:]
+    return row
+
+
+def _fill_mi_header(row, control_row):
+    """Forward fill blank entries in row but only inside the same parent index.
+
+    Used for creating headers in Multiindex.
+    Parameters
+    ----------
+    row : list
+        List of items in a single row.
+    control_row : list of bool
+        Helps to determine if particular column is in same parent index as the
+        previous value. Used to stop propagation of empty cells between
+        different indexes.
+
+    Returns
+    -------
+    Returns changed row and control_row
+    """
+    last = row[0]
+    for i in range(1, len(row)):
+        if not control_row[i]:
+            last = row[i]
+
+        if row[i] == "" or row[i] is None:
+            row[i] = last
+        else:
+            control_row[i] = False
+            last = row[i]
+
+    return row, control_row
+
+
+def _pop_header_name(row, index_col):
+    """
+    Pop the header name for MultiIndex parsing.
+
+    Parameters
+    ----------
+    row : list
+        The data row to parse for the header name.
+    index_col : int, list
+        The index columns for our data. Assumed to be non-null.
+
+    Returns
+    -------
+    header_name : str
+        The extracted header name.
+    trimmed_row : list
+        The original data row with the header name removed.
+    """
+    # Pop out header name and fill w/blank.
+    i = index_col if not is_list_like(index_col) else max(index_col)
+
+    header_name = row[i]
+    header_name = None if header_name == "" else header_name
+
+    return header_name, row[:i] + [""] + row[i + 1 :]