55 lines
1.5 KiB
Python
55 lines
1.5 KiB
Python
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import numpy as np
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from scipy import sparse as sp
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from . import is_scalar_nan
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from .fixes import _object_dtype_isnan
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def _get_dense_mask(X, value_to_mask):
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if is_scalar_nan(value_to_mask):
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if X.dtype.kind == "f":
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Xt = np.isnan(X)
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elif X.dtype.kind in ("i", "u"):
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# can't have NaNs in integer array.
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Xt = np.zeros(X.shape, dtype=bool)
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else:
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# np.isnan does not work on object dtypes.
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Xt = _object_dtype_isnan(X)
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else:
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Xt = X == value_to_mask
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return Xt
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def _get_mask(X, value_to_mask):
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"""Compute the boolean mask X == value_to_mask.
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Parameters
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----------
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X : {ndarray, sparse matrix} of shape (n_samples, n_features)
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Input data, where ``n_samples`` is the number of samples and
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``n_features`` is the number of features.
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value_to_mask : {int, float}
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The value which is to be masked in X.
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Returns
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-------
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X_mask : {ndarray, sparse matrix} of shape (n_samples, n_features)
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Missing mask.
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"""
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if not sp.issparse(X):
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# For all cases apart of a sparse input where we need to reconstruct
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# a sparse output
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return _get_dense_mask(X, value_to_mask)
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Xt = _get_dense_mask(X.data, value_to_mask)
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sparse_constructor = (sp.csr_matrix if X.format == 'csr'
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else sp.csc_matrix)
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Xt_sparse = sparse_constructor(
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(Xt, X.indices.copy(), X.indptr.copy()), shape=X.shape, dtype=bool
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)
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return Xt_sparse
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