在某些函数名称中尾随“ $”的含义是什么？

Question

I recently looked at some vba source at Microsoft: [Convert Fractions to Decimal Values][1]

[1]: https://support.microsoft.com/en-us/kb/185424 and I noticed that several functions had a trailing "$", specifically trim$(), left$(), and mid$(). My question is: what does the "$" signify?

I downloaded the microsoft function and it ran correctly under Excel 2007.

Since VBA trim() works differently from the worksheet function trim(), I wrote a small program to compare the operation of the 3 possible trim() calls. I found that trim() and trim$() produced identical output. worksheetfunction.trim(), of course, produces output that has extraneous space characters removed from inside the string.

I am very curious about the trailing "$", and will be grateful for enlightenment!

Thank you, Dave

Answer 1

To quote from https://bytes.com/topic/access/answers/196893-difference-between-left-left-function

Allen Browne
The trailing $ is a type declaration character for the String data type in VBA. The result returned from Left$() is a string, whereas Left() returns a Variant. You must use Left(), not Left$() if there is any chance of Null values, since the Variant can be Null but the String cannot.

That post has a full worked example

Answer 2

The syntax is a left-over habit from ancient history. In early versions of Basic variables did not have to be declared but data types were implied by the name of the variable. Any variable ending with $ was a string and any variable ending with % was an integer.

FORTRAN had a similar convention: any variable starting with the letters I, J, K, L, M or N were integers, all others were real.