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# Single atom array

An array with a single atom is referred to as a singleton. All singletons with the same atom display the same way. However, the fact that they have different ranks affects how verbs act on them. This can be a pitfall for beginners. It is important to remember that if it displays like an atom, but does not behave like one, then check its rank.

       atom =. 5
       list =. 1 $ 5
       atom
    5

       list	NB. list looks like atom
    5

       atom + 23 23 23
    28 28 28

       list + 23 23 23	NB. but does not behave like atom
    ¦length error
    ¦   list    +23 23 23
       # $ atom	NB. rank of atom is 0
    0

       # $ list	NB. rank of list is 1
    1

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