numpy.s_#

numpy.s_=<numpy.lib._index_tricks_impl.IndexExpressionobject>#

A nicer way to build up index tuples for arrays.

Note

Use one of the two predefined instancesindex_exp ors_rather than directly usingIndexExpression.

For any index combination, including slicing and axis insertion,a[indices] is the same asa[np.index_exp[indices]] for anyarraya. However,np.index_exp[indices] can be used anywherein Python code and returns a tuple of slice objects that can beused in the construction of complex index expressions.

Parameters:

maketuplebool

If True, always returns a tuple.

See also

s_

Predefined instance without tuple conversion:s_ = IndexExpression(maketuple=False). Theindex_exp is another predefined instance that always returns a tuple:index_exp = IndexExpression(maketuple=True).

Notes

You can do all this withslice plus a few special objects,but there’s a lot to remember and this version is simpler becauseit uses the standard array indexing syntax.

Examples

Try it in your browser!

>>>importnumpyasnp>>>np.s_[2::2]slice(2, None, 2)>>>np.index_exp[2::2](slice(2, None, 2),)

>>>np.array([0,1,2,3,4])[np.s_[2::2]]array([2, 4])

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