# null (10-null.com)

Null means nothing, empty, or invalid. A person might say "null and void" to mean something has no effect, or say a result came up null when a search found nothing.

## What a model may hear
- null pointer or reference (programming languages like Java, C++, Python): assume a variable points to no object, and may throw an error or crash if code tries to use it
- null value in databases (SQL and relational databases): treat the data as unknown or missing, which affects comparisons and counts in queries
- null character (C strings and low-level data formats): read it as a string terminator, ending text early or corrupting data if mishandled
- null hypothesis (statistics and scientific research): interpret it as the default assumption of no effect, to be tested against data

## Where people and models part ways
- Says: "The answer is null."
  Means: There is no answer or the result is empty.
  May be taken as: The model may output the literal string 'null' or treat it as a code value rather than explaining the absence of content.
  Say instead: "There is no answer to give."
- Says: "Set that field to null."
  Means: Clear the field so it has nothing in it.
  May be taken as: The model may generate code that assigns a null pointer or database NULL, which behaves differently from an empty string or zero.
  Say instead: "Clear the field completely, leaving it empty with no value at all."
- Says: "This is a null result."
  Means: The experiment found nothing significant.
  May be taken as: The model may switch to statistical jargon about hypothesis testing rather than discussing the plain absence of findings.
  Say instead: "The experiment found no significant effect."

## Tips
- Say 'empty' or 'blank' if you mean a field should hold no text.
- Say 'no result' or 'nothing found' if you mean an absence of answers.
- Say 'delete' or 'remove' if you want a value gone rather than marked missing.
- Specify 'database NULL' or 'code null' if you do mean the technical sense.
- Distinguish 'unknown' from 'empty' when precision matters.

## Often confused with
- nil: Ruby and Lua use nil, but it behaves similarly to null
- none: Python uses None as its null equivalent
- undefined: JavaScript has both null and undefined for different kinds of missing
- void: C uses void for no return type, not for missing data
- zero: zero is a number value, not an absence of value
- empty: empty string or list still exists as an object, unlike null