How to check if array is not empty

Question

How to check if the array is not empty  I did this   if not self table 5  is None    Is this the right way

User · Answer

print len a list     As many languages have the len   function  in Python this would work for your question   If the output is not 0  the list is not empty

User · Answer

if self table      print  It is not empty    Is fine too

User · Answer

There s no mention of numpy in the question  If by array you mean list  then if you treat a list as a boolean it will yield True if it has items and False if it s empty   l       if l      print  list has items   if not l      print  list is empty

User · Answer

with a as a  numpy array  use   if a size     print  array is not empty      in Python  objects like  1 2 3  are called lists  not arrays

User · Answer

If you are talking about Python s actual array  available through import array from array   then the principle of least astonishment applies and you can check whether it is empty the same way you d check if a list is empty   from array import array an array   array  i     an array of ints  if an array      print  this won t be printed    an array append 3   if an array      print  this will be printed

User · Answer

len self table  checks for the length of the array  so you can use if-statements to find out if the length of the list is greater than 0  not empty    Python 2   if len self table   gt  0       Do code here   Python 3   if len self table   gt  0        Do code here   It s also possible to use   if self table       Execute if self table is not empty else       Execute if self table is empty   to see if the list is not empty

User · Answer

I can t comment yet  but it should be mentioned that if you use numpy array with more than one element this will fail  if l      print  quot list has items quot   elif not l      print  quot list is empty quot   the error will be  ValueError  The truth value of an array with more than one element is ambiguous  Use a any   or a all

User · Answer

An easy way is to use Boolean expressions  if not self table 5       print  list is empty   else      print  list is not empty    Or you can use another Boolean expression   if self table 5             print  list is empty   else      print  list is not empty

[python] How to check if array is not empty?

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