import numpy as np from pandas._typing import ArrayLike from pandas import ( DataFrame, Index, ) from pandas.core.internals.api import _make_block from pandas.core.internals.managers import BlockManager as _BlockManager def create_dataframe_from_blocks( blocks: list[tuple[ArrayLike, np.ndarray]], index: Index, columns: Index ) -> DataFrame: """ Low-level function to create a DataFrame from arrays as they are representing the block structure of the resulting DataFrame. Attention: this is an advanced, low-level function that should only be used if you know that the below-mentioned assumptions are guaranteed. If passing data that do not follow those assumptions, subsequent subsequent operations on the resulting DataFrame might lead to strange errors. For almost all use cases, you should use the standard pd.DataFrame(..) constructor instead. If you are planning to use this function, let us know by opening an issue at https://github.com/pandas-dev/pandas/issues. Assumptions: - The block arrays are either a 2D numpy array or a pandas ExtensionArray - In case of a numpy array, it is assumed to already be in the expected shape for Blocks (2D, (cols, rows), i.e. transposed compared to the DataFrame columns). - All arrays are taken as is (no type inference) and expected to have the correct size. - The placement arrays have the correct length (equalling the number of columns that its equivalent block array represents), and all placement arrays together form a complete set of 0 to n_columns - 1. Parameters ---------- blocks : list of tuples of (block_array, block_placement) This should be a list of tuples existing of (block_array, block_placement), where: - block_array is a 2D numpy array or a 1D ExtensionArray, following the requirements listed above. - block_placement is a 1D integer numpy array index : Index The Index object for the `index` of the resulting DataFrame. columns : Index The Index object for the `columns` of the resulting DataFrame. Returns ------- DataFrame """ block_objs = [_make_block(*block) for block in blocks] axes = [columns, index] mgr = _BlockManager(block_objs, axes) return DataFrame._from_mgr(mgr, mgr.axes)