Building off TW Tones, here's a simple temperature converter using filters to pull an input number from a state tiddler ( $:/_br/converter/state ) field named "temp-f" and use filter math operators to convert it to celsius before editing another field (temp-c) in the same state tiddler. You can paste the following code into a tiddler to play around with...
``` <table> <tr> <th colspan="2">Fahrenheit > Celsius</th> </tr> <tr> <td style="width:5em"><$edit-text tiddler="$:/_br/converter/state" field="temp-f"/></td> <td> <$list filter="$:/_br/converter/state +[get[temp-f]subtract[32]multiply[5]divide[9]precision[4]]" variable="convert-c"> <$text text=<<convert-c>>/>° Celsius (C) </$list> </td> </tr> </table> ``` On Wednesday, September 9, 2020 at 7:19:11 PM UTC-7 TW Tones wrote: > Bob, > > 1. Is there a simple concatenation operator, like & or + that can be used >> to concatenate strings? I know that a macro can do it but that seems very >> confusing to a simple mind like me. > > > 1. Concatenation > > There are many ways to concatenate with tiddlywiki, although for good > reasons in may seem not as strait forward as you would expect. In part > because where do you want this concatenated result used? > Please provide a descriptive example of what you are currently try to > achieve. > > With concatenation you will find these methods useful > > - Define a macro in which the concatenation occurs > - You can use $(currentTiddler)$ and parameter $param$ for simple > substitutions > - Wiki fy that macro (with the same name is ok) just before you use it > say in a filter and some parameters > - You can use add-prefix/split/join/splitregext and other string > handling. > > 2. Is there a way of doing simple arithmetic, say increment a variable or >> add some variables together? The manual implies that it is possible in a >> filter but I want to do it outside of a filter. > > > 2. Most if not all the mathematics functions in standard tiddlywiki are > "filter operators", so they must be used in filters > > However; > > - Use triple braces to present the result of a calculation in line as > a parameter. > {{{ [your maths filter] }}} but you may need to turn the result into > text <$text text={{{ [your maths filter] }}}/> > - You can use other maths plugins like Evans formula plugin he uses > Mushroom brackets (= maths =), calc widget and others > > In closing if you are reluctant to learn filters in more detail, I suggest > you jump in. Filters are so powerful once you come to understand them your > powers are almost unlimited. > > Regards > TW Tones > > On Thursday, 10 September 2020 11:13:06 UTC+10, Bob Jansen wrote: >> >> >> >> >> >> bobj >> >> -- You received this message because you are subscribed to the Google Groups "TiddlyWiki" group. To unsubscribe from this group and stop receiving emails from it, send an email to tiddlywiki+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/tiddlywiki/65ea8234-f9cb-4000-b738-dd5cb0db2693n%40googlegroups.com.