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I want to remove the whole numpy array. For instance, if I make array A like

A = np.zeros((2,3))

I want to remove the whole array A and want to reuse the name 'A' in other purpose.

Are there any codes (functions) to delete the array?

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  • 2
    Python is a memory-managed language, and objects are automatically reclaimed once their reference count reaches zero. Commented May 11, 2018 at 6:21
  • @juanpa.arrivillaga ... except numpy is not really python and doesn't necessarily work that way Commented Jun 12, 2020 at 2:54
  • @Jivan yes, it is. And yes, it does. Commented Jun 12, 2020 at 2:55
  • well, try del my_numpy_array_taking_50gb_in_memory and see what happens in htop then — memory is still allocated Commented Jun 12, 2020 at 2:57
  • @Jivan read the following: stackoverflow.com/questions/15455048/releasing-memory-in-python Commented Jun 12, 2020 at 5:50

2 Answers 2

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I want to remove the whole array A

Easy :

del A

want to reuse the name 'A' in other purpose.

Similarly easy :

A = whateverElse  # associate A with whateverElse, so simple :o)
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8 Comments

this doesn't free the memory. somehow the array continues to be attached to the memory (even though the variable is not accessible anymore)
@Jivan - sure, such cases are possible. May test A.flags before having done the del A to see more details. Numpy uses smart structures for vector/matrix/tensor data storage & manipulation. Some even do not "own" its own data & are just a lightweight-"reader"-helper into another numpy-object's data, so deleting such non-"owner" will for obvious reasons delete just the lightqweight-"reader"-helper, not the fat-(_foreign by ownership_)-data itself.
any idea how to free memory from the fat data in these cases, then?
@Jivan there is no way to explicitly free memory in Python
@juanpa.arrivillaga does it mean that if we create a 50gb array in memory and del doesn't free it, then there's no other way to free this memory than killing the process?
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Just assign A to something else. As @juanpa.arrivillaga said, Python will take care of the now "un-referenced" array and do any garbage collection itself.
e.g. A = "new string"

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