I did a survey of naming conventions across a variety of languages:

Language | Predicate true for at least one | Predicate true for all | At least one equals given value | All elements equal given value |
---|---|---|---|---|

C# | `Any` |
`All` |
`Contains` |
– |

C++ | `any_of` |
`all_of` |
– | – |

Clojure | `some` |
`every?` |
– | – |

F# | `exists` |
`forall` |
`contains` |
– |

Haskell | `any` |
`all` |
`elem` |
– |

Java | `anyMatch` |
`allMatch` |
`contains` |
– |

JavaScript | `some` |
`every` |
`includes` |
– |

Kotlin | `any` |
`all` |
`contains` |
– |

Matlab | `any` |
`all` |
`ismember` |
– |

PHP | `array_some` |
`array_every` |
`in_array` |
– |

Python | `any` |
`all` |
… `in` … |
– |

R | `any` |
`all` |
…`%in%` … |
`all.equal` |

Ruby | `any?` |
`all?` |
`include?` |
– |

Rust | `any` |
`all` |
`contains` |
– |

Scala | `exists` |
`forall` |
`contains` |
– |

This includes nearly all the most popular & “most loved” languages in the latest Stack Overflow survey that have closures or other predicate-like constructs.

Some observations:

- For the first function:
- 10 use the word “any”
- 3 use “some”
- 2 use “exists”

- For the second function:
- 12 use the word “all”
- 3 use the word “every”

- For the third function:
- 6 use the word “contains”
- 3 use “in”
- 2 use “include(s)”
- 1 uses “elem”

- No language strives for parallel naming between the first and third.
- Only one language implements an “all elements equal a given value” function — at least that I could find. If any of these other languages have one and I missed it, please let me know and I'll update the table. (Rust does have an
`all_equal`

, but it seems to mean all equal to*each other*, not*to a given value*)