I have a very similar problem.
There are some number of devices that are monitored using SNMP. It could be great to have a set of Screens with information about each device, starting with the general info (to see clearly: what device is used at the moment). Something like the following:

Device: megadevicehostname, OS: Super-OS v23.45
System: OurSystem vAAA.BBB spCC.DD build XXX

The problem is that each line contains info from the several items:

So, it is necessary to concatenate the values of the listed items as well as some additional text constants (strings "Device: ", ", OS: ", "sp", dot between the Major- and Minor-versions, etc.). Item types are mostly text ("Character"), but some of them could be numeric (for example, Major & Minor as well as Build Number are "Numeric unsigned").

It is possible to insert into a Screen the separate value only (for example, the resource "Plain Text", then – specific Item). However, with such approach the resulting Screen will be cumbersome and hard for perception: there will be 9 lines instead of 2 (additionally containing needless Item names).

It is possible to use some external script that will collect information from devices, perform it into needed format and then send into Zabbix using zabbix_sender. However, it seems stupid to write (and then maintain) an additional scripts for SNMP-polling when Zabbix-server has it own embedded SNMP-poller.

It could be great to concatenate several values into the single value using the Calculated Items mechanism; however, at the moment Calculated Items supports only Numerc types, operations and functions

As a solution, I'd like to have a Calculated Items that could have a string type ("Character" or "Text") and allow string operations (at list – concatenation, then could be substring, etc.) on any operand (numeric operands should be converted onto strings).

Another use case would be to receive the previous item value in alert emails

ie, I was going to add last("key", #2) as calculated item, but unfortunately, a referenced item has "Character" type

For notification messages you can use something like

{{HOST.HOST1}:{ITEM.KEY1}.last(#2)}

Sure, but then I'll have to add a special action for it

You would still need it with calculated item, no? I don't fully understand what you are trying to achieve...

With calculated item, I'll be able to use "standard" action similar to

1. {ITEM.NAME1}: {ITEM.VALUE1}
2. {ITEM.NAME2}: {ITEM.VALUE2}
3. {ITEM.NAME3}: {ITEM.VALUE3}

that's not big deal, but sometimes can be useful

and it's not obvious why calculated items can't be Character or Text if some functions (like last()) support them

It took some time, but I think I've got it now.

So you basically need a calculated item with last(#2) aka prev() because even if you would use prev() in trigger expression {ITEM.VALUE} would resolve to last().

Actually, you may be interested in ZBXNEXT-3008 as well.

Another use-case for this feature request.

There is task: to have a text item that contains the top-5 list of processes that are loading CPU at the moment on the Windows host.

We can use a PowerShell script for this task; but it's a bad solution: PowerShell is a "hard" enough – it takes a lot of time and CPU during start, and it influences itself onto the result.
Acceptable result is to use the wmi.getall[...] metric (to extract a list of "heavy" processes) and JavaScript preprocessing (to exclude "Idle" and "_Total" records, summarize values for several processes with the same names and to sort the output). As a result, we can have, for example, the following (it is a single multi-line text value):

msedge,648
powershell,84
svchost,33

The only problem is that the resulting digits could be more than 100% on multi-core CPU systems. So, ideally, we would like to have all these numbers being divided by a number of cores (eight cores in this example):

msedge,81
powershell,10.5
svchost,4.125

The number of CPU cores could be obtained using a system.cpu.num metric. However, it's impossible to access the values of another items in a preprocessing stage.

This task could be solved using a calculated item and some script in its preprocessing; but calculated items still do not support any operations with non-numeric operands (multiline text value in this example).

This functionality is coming in 6.2, the work is already in progress. It is also possible (no guarantees!) that we manage to include it into 6.0.

Available in versions:

• pre-6.0.0beta3 - aa982430619, 062d59b831c

Documentation updated:

• String functions
• What's new 6.0

Great news, it is coming in Zabbix 6.0 LTS!

Yeah ! Thank you very much !

Hi! Very good news, thanks!

Documentation updated:

It seems that both links are not very accurate: the first one refers to the current version (5.4) instead of 6.0; the second one refers to the Prometheus metrics processing.

An additional question: will it be possible to use a string functions for the items with Numeric types?
For example:

• concatenate a string constants, "Numeric (unsigned)" value and "Character" type value (see examples in the very first comment of this issue)?
• trim, cut or replace some substring from the Numeric types (for example: to replace the "dot" character by the "comma" in the "Numeric (float)" value)?

If not, maybe – it's reasonable to have a some simple additional function like "string()" for transforming of any Numeric value onto the string?

Thanks for your feedback!

Both links has been fixed.

All string functions can be used for all data types without any transformations.

sasha, great, thanks!