craftbeerpi4-pione/venv3/lib/python3.7/site-packages/pandas/io/excel/_util.py
2021-03-03 23:49:41 +01:00

235 lines
5.4 KiB
Python

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",
"ods": "odf",
}
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 as err:
raise ValueError(f"No Excel writer '{engine_name}'") from err
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(f"Invalid column name: {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):
raise ValueError(
"Passing an integer for `usecols` is no longer supported. "
"Please pass in a list of int from 0 to `usecols` inclusive instead."
)
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 :]