[SOLVED] BBC weather RSS Latest Title split to <64 characters for Velbus OLED (AKA Splitting Strings)

[rlkoshak (Rich Koshak)]

@MDAR

Well, I really don’t understand how the split command works, is it splitting up to the stated character, or after it?

I think the key thing is the split command doesn’t actually change the String. It returns an array with copies of the String split on the given character. So the command

val weather0 = BBCWeatherRSS_LatestTitle.state.toString.split(',').get(0)

and you never use weather0 is a noop (does nothing). It doesn’t change BBCWeatherRSS_LatestTitle.state.toString for the succeeding lines so there is no reason for it to exist.

@MDAR

this line :
val weather0 = BBCWeatherRSS_LatestTitle.state.toString.split(',').get(0)

give a return of “Today: Light Cloud”

Which you stated and it appears to be born out in the code you don’t actually use. So why split it out in the first place?

@MDAR

and val weather1 = BBCWeatherRSS_LatestTitle.state.toString.split(':').get(1)
creates a return of “Light Cloud” (the later being what I wanted)

Right, but I think the part you missed is that the weather1 line is operating on the entire text, not just on what is in weather0. Had you written it as:

val weather1 = weather0.split(":").get(1)

then weather0 would be a useful line. But as you should see, you don’t need that first line because the second Item in the list when you split the whole text on : will be the part you want anyway. So you can skip it.

@MDAR

I can see from your example that you take that first split and divide it again at the comma.

Where your PARTS variables must contain the various bits of text “between” the “:”

What is confusing me is the .get(0) vs .get(1) / .get(2) / .get(3) etc

My code should be (unless I have a typo) functionally equivalent to what your original code does. The important things to realize are:

• calling split does not change the original text; each one of your weatherX lines is operating on the full text from the RSS feed.
• split returns a list of the parts of the string split on the occurrences of ‘:’ in this case, excluding the ‘:’. So if you have the string foo:bar:baz, calling split(‘:’).get(0) will be foo and split(‘:’).get(2) will be baz. You are getting the Nth part of the String after the split. As with most programming, we start with 0 instead of 1

So just split the String once and save the list to a variable (parts). Then pull out the parts that you want and save those to their own variables.

@MDAR

I had tried grouping string items before, but it didn’t work, so I assumed it just wasn’t possible.

You can’t use an aggregation function with String Items (what’s the AVG of a bunch of Strings?). Maybe you tried to do that?

@MDAR

However I was trying to read values from multiple string items

This should be possible. I’d have to see what you tried.

@MDAR

The ONLY reason I’ll not add that particular edit is that being able to comment out a single line to disable the MemoText on a single glass panel is quite easy, rather than having to edit the Item to remove the group.

In general, editing data (I’m calling Items data here for sake of argument) is safer than editing code. This is why I always fall on the side of making the changes in .items files and sometimes .map files and the like before I’d write a Rule that I would expect to need to edit in the future. It is easier to accidentally introduce subtle errors in code. If you introduce an error in a .items file, it will usually break the whole file and you immediately know.

@MDAR

However, thinking about it, adding or removing MemoText Items from a selection of String Groups would make it much easier for a Panel to “subscribe” to a range of different information.

Another good reason. Other approaches could be using an enable/disable proxy Item for each to turn it on or off. But Group membership would be much easier.

@MDAR

val parts = BBCWeatherRSS_LatestTitle.state.toString.split(‘:’).get(1)

DOH! Dumb mistake. Get rid of the .get(1) at the end. It shouldn’t be there.

@MDAR

Is there some cunning way of only requesting the 4th split of data is if it present in the string?

if(parts.size >= 4) parts.get(3)

So using the trinary operator (one line if statement)

val weather3 = if(parts.size >= 4) parts.toString.get(3) else ""

The size of the parts array tells you how many segments the String was split into.

@MDAR

Can I spilt the incoming text after the condition section, use ALL (whatever that might be) text after the “,” and simply replace "Minimum " with "Min " and (if it occurs) "Maximum " with "Max ".
And remove “Temperature” or replace it with " " ???

You can do that too. Split on “,” and get(1). The use replace(“Minimum”, “Min”) and replace(“Maximum”, “Max”) and replace(“Temperature”, “”).

You can even do it in one line.

message = BBCWeatherRSS_LatestTitle.state.toString.split(',').get(1).replace("Minimum", "Min").replace("Maximum", "Max").replace("Temperature", "")