# filter (10-filter.com)

A filter is something that removes what you do not want. People talk about water filters, air filters, or filters on photos that change how things look. It keeps the good and leaves out the bad.

## What a model may hear
- array or list filter function (programming languages like Python, JavaScript, SQL): Return only items that pass a test function, often silently dropping the rest
- signal processing filter (audio, image processing, electronics): Apply a mathematical transformation to frequencies or pixels, altering the data rather than just selecting
- network packet filter (firewalls, routers, system administration): Block or allow traffic based on rules, possibly logging or rejecting connections
- convolutional filter (machine learning, neural networks): A learned matrix of weights applied to input data to detect features
- email or content filter (mail servers, moderation systems): Classify and redirect, quarantine, or delete messages based on content rules

## Where people and models part ways
- Says: "Filter out the noise"
  Means: Remove irrelevant information
  May be taken as: Apply an audio low-pass filter or drop data rows without asking
  Say instead: "Remove irrelevant details and keep the important points"
- Says: "Add a filter to make it warmer"
  Means: Change the tone or mood of the text
  May be taken as: Apply an image color temperature adjustment or audio EQ
  Say instead: "Rewrite this in a friendlier, warmer tone"
- Says: "Filter the results"
  Means: Show me only what matches my criteria
  May be taken as: Execute a programmatic filter function that may exclude edge cases
  Say instead: "Show only results where the date is after 2020"
- Says: "Run it through a filter"
  Means: Check it for problems or clean it up
  May be taken as: Pass data through a trained model classifier or firewall rule set
  Say instead: "Check this for errors and remove anything inappropriate"

## Tips
- Say what you want to keep, not just what to remove
- Specify the kind of thing you are filtering: words, numbers, ideas, or options
- Say whether you want a simple yes-no choice or a ranked list
- Mention if hidden items should still exist somewhere or be gone forever
- When you mean tone or style, say rewrite or adjust instead of filter

## Often confused with
- sort: reorders rather than removes
- search: finds matches rather than excluding non-matches
- clean: fixes or standardizes rather than selecting
- mask: hides without removing
- reduce: combines into a single result
- map: transforms each item rather than selecting