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Diffstat (limited to 'doc/source/user/quickstart.rst')
| -rw-r--r-- | doc/source/user/quickstart.rst | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/doc/source/user/quickstart.rst b/doc/source/user/quickstart.rst index 5ef8b145f..262f53c1c 100644 --- a/doc/source/user/quickstart.rst +++ b/doc/source/user/quickstart.rst @@ -884,6 +884,17 @@ The ``copy`` method makes a complete copy of the array and its data. [ 8, 10, 10, 11]]) +Sometimes ``copy`` should be called after slicing if the original array is not required anymore. +For example, suppose ``a`` is a huge intermediate result and the final result ``b`` only contains +a small fraction of ``a``, a deep copy should be made when constructing ``b`` with slicing:: + + >>> a = np.arange(int(1e8)) + >>> b = a[:100].copy() + >>> del a # the memory of ``a`` can be released. + +If ``b = a[:100]`` is used instead, ``a`` is referenced by ``b`` and will persist in memory +even if ``del a`` is executed. + Functions and Methods Overview ------------------------------ |