# `not`


_Not zero_
```syntax
not x    not[x]
```

Returns `0b` where `x` **not** equal to zero, and `1b` otherwise.

Applies to all data types except symbol, and to items of lists, dictionary values and table columns, referring to the underlying data value.

Nulls and infinities never equal zero.
```q
q)not -1 0 1 2
0100b

q)not "abc","c"$0
0001b

q)not `a`b!(-1 0 2;"abc","c"$0)
a| 010b
b| 0001b

q)not 2000.01.01 2020.06.30
10b

q)not 00:00:00
1b

q)not 12:00:00.000000000
0b

q)not (0W;-0w;0N)
000b
```

An atomic function. 

`not` is a [multithreaded primitive](../kb/mt-primitives.md).

---

[`neg`](neg.md) 


[Logic](../basics/by-topic.md#logic)


_Q for Mortals_
[§4.3.2 Not Zero `not`](/q4m3/4_Operators/#432-not-zero-not)