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in1d(ar1, ar2, assume_unique=False, invert=False)

Returns a boolean array the same length as :None:None:`ar1` that is True where an element of :None:None:`ar1` is in :None:None:`ar2` and False otherwise.

We recommend using isin instead of in1d for new code.

Notes

in1d can be considered as an element-wise function version of the python keyword :None:None:`in`, for 1-D sequences. in1d(a, b) is roughly equivalent to np.array([item in b for item in a]) . However, this idea fails if :None:None:`ar2` is a set, or similar (non-sequence) container: As ar2 is converted to an array, in those cases asarray(ar2) is an object array rather than the expected array of contained values.

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Parameters

ar1 : (M,) array_like

Input array.

ar2 : array_like

The values against which to test each value of :None:None:`ar1`.

assume_unique : bool, optional

If True, the input arrays are both assumed to be unique, which can speed up the calculation. Default is False.

invert : bool, optional

If True, the values in the returned array are inverted (that is, False where an element of :None:None:`ar1` is in :None:None:`ar2` and True otherwise). Default is False. np.in1d(a, b, invert=True) is equivalent to (but is faster than) np.invert(in1d(a, b)) .

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Returns

in1d : (M,) ndarray, bool

The values :None:None:`ar1[in1d]` are in :None:None:`ar2`.

Test whether each element of a 1-D array is also present in a second array.

See Also

isin

Version of this function that preserves the shape of ar1.

numpy.lib.arraysetops

Module with a number of other functions for performing set operations on arrays.

Examples

>>> test = np.array([0, 1, 2, 5, 0])
... states = [0, 2]
... mask = np.in1d(test, states)
... mask array([ True, False, True, False, True])
>>> test[mask]
array([0, 2, 0])
>>> mask = np.in1d(test, states, invert=True)
... mask array([False, True, False, True, False])
>>> test[mask]
array([1, 5])
See :

Back References

The following pages refer to to this document either explicitly or contain code examples using this.

numpy.isin numpy.in1d numpy.ma.extras.in1d numpy.ma.extras.isin

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GitHub : /numpy/lib/arraysetops.py#519
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