summaryrefslogtreecommitdiff
path: root/numpy/lib/function_base.py
diff options
context:
space:
mode:
Diffstat (limited to 'numpy/lib/function_base.py')
-rw-r--r--numpy/lib/function_base.py24
1 files changed, 24 insertions, 0 deletions
diff --git a/numpy/lib/function_base.py b/numpy/lib/function_base.py
index 7eeed7825..38acfd2d5 100644
--- a/numpy/lib/function_base.py
+++ b/numpy/lib/function_base.py
@@ -764,6 +764,30 @@ def copy(a, order='K', subok=False):
>>> x[0] == z[0]
False
+ Note that np.copy is a shallow copy and will not copy object
+ elements within arrays. This is mainly important for arrays
+ containing Python objects. The new array will contain the
+ same object which may lead to surprises if that object can
+ be modified (is mutable):
+
+ >>> a = np.array([1, 'm', [2, 3, 4]], dtype=object)
+ >>> b = np.copy(a)
+ >>> b[2][0] = 10
+ >>> a
+ array([1, 'm', list([10, 3, 4])], dtype=object)
+
+ To ensure all elements within an ``object`` array are copied,
+ use `copy.deepcopy`:
+
+ >>> import copy
+ >>> a = np.array([1, 'm', [2, 3, 4]], dtype=object)
+ >>> c = copy.deepcopy(a)
+ >>> c[2][0] = 10
+ >>> c
+ array([1, 'm', list([10, 3, 4])], dtype=object)
+ >>> a
+ array([1, 'm', list([2, 3, 4])], dtype=object)
+
"""
return array(a, order=order, subok=subok, copy=True)