In ML, NONE is one of the constructors of the 'a option datatype. Partial functions evaluate to NONE when applied to arguments not in their domain. For example, the function lookup : (int * string) list -> int -> string option may be implemented as follows:

fun lookup nil x = NONE
  | lookup (n, s)::t x = if x = n then SOME(s) else lookup t x

For more details, see the writeup on the option datatype.

Name of the object in the Python computer language which acts like other languages null pointer. Since there is no direct access to pointers in Python the none object is just that rather than a null pointer

None (?), a. & pron. [OE. none, non, nan, no, na, AS. nan, fr. ne not + an one. . See No, a. & adv., One, and cf. Non-, Null, a.]


No one; not one; not anything; -- frequently used also partitively, or as a plural, not any.

There is none that doeth good; no, not one. Ps. xiv. 3.

Six days ye shall gather it, but on the seventh day, which is the Sabbath, in it there shall be none. Ex. xvi. 26.

Terms of peace yet none Vouchsafed or sought. Milton.

None of their productions are extant. Blair.


No; not any; -- used adjectively before a vowel, in old style; as, thou shalt have none assurance of thy life.

None of, not at all; not; nothing of; -- used emphatically. "They knew that I was none of the register that entered their admissions in the universities." Fuller. -- None-so-pretty Bot., the Saxifraga umbrosa. See London pride (a), under London.


© Webster 1913.

None, n. [F.]

Same as Nones, 2.


© Webster 1913.

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