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author | wtli <liwt31@163.com> | 2019-03-06 17:33:48 +0800 |
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committer | wtli <liwt31@163.com> | 2019-03-14 21:25:37 +0800 |
commit | e0ffa191ade1ac8548cad38a73fecc9f2528f9ef (patch) | |
tree | 1dd255c6ce897a36ed838fed356d821b53f09335 /doc/source/reference/arrays.indexing.rst | |
parent | 1a15c074f002cb7520e347392841b6b371c71361 (diff) | |
download | numpy-e0ffa191ade1ac8548cad38a73fecc9f2528f9ef.tar.gz |
DOC: add copy on slicing notice
Diffstat (limited to 'doc/source/reference/arrays.indexing.rst')
-rw-r--r-- | doc/source/reference/arrays.indexing.rst | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/doc/source/reference/arrays.indexing.rst b/doc/source/reference/arrays.indexing.rst index 3a319ecca..0c0c8dff6 100644 --- a/doc/source/reference/arrays.indexing.rst +++ b/doc/source/reference/arrays.indexing.rst @@ -57,6 +57,17 @@ interpreted as counting from the end of the array (*i.e.*, if All arrays generated by basic slicing are always :term:`views <view>` of the original array. +.. note:: + + NumPy slicing creates a :term:`view` instead of a copy as in the case of + builtin Python sequences such as string, tuple and list. + Care must be taken when extracting + a small portion from a large array which becomes useless after the + extraction, because the small portion extracted contains a reference + to the large original array whose memory will not be released until + all arrays derived from it are garbage-collected. In such cases an + explicit ``copy()`` is recommended. + The standard rules of sequence slicing apply to basic slicing on a per-dimension basis (including using a step index). Some useful concepts to remember include: |