Forum Discussion
Why does List.MatchesAll return true for an empty list?
The function documentation says that List.MatchesAll returns true if the condition function is satisfied by all values in the list, otherwise returns false.
Given a value x, I'd expect List.MatchesAll({}, each _ = x) to return false - how can the contents of the list all satisfy the condition of being equal to x if the list does not have any contents against which to test the condition?
For every value of x I've tried:
List.MatchesAll({}, each _ = x) returns true
List.MatchesAny({}, each _ = x) returns false
List.Contains({}, x) returns false
Can anyone explain this behaviour and why it is different for List.MatchesAll than it is for List.MatchesAny and List.Contains?
1 Reply
- mahoneypat
Microsoft Employee
I wouldn't have guessed that behavior either, but I suspect it starts to iterate through the list with a TRUE condition, and since the list is empty there are no iterations/evaluations. If you use {null} instead of {} it evaluates as FALSE, as it does do one iteration.
Pat
