Count substring occurences inside a string returned from sensor

qm28jSLtTnkW · September 10, 2025, 10:55am

Hi all,
I have to resort to your valuable time to ask for help in this situation:

what I have

a sensor from an integration https://github.com/zulufoxtrot/ha-zyxel that returns a string value


{{ states('sensor.zyxel_cellular_intf_current_band') }}

B7,B1,B3,B20,n78

Result type: string

what I wish for

a way to count how many times the different strings related to cell bands appears over time, I tought to build an automation that every time the state changes it increment a counter (one per band) but I cannot figure how to do it since the string returned from the sensor in different every time and not all the cells are present. (es. the next value/state could be ‘B3, B1, n78’)

So I think I need a way to iterate the possible values (which i know) comparing them to the values in the string and in the meantime update the related counter…but how??

Any ideas?

Thank you!

tom_l · September 10, 2025, 11:11am

So something like this?

template:
  - sensor:
      - name: B7 Count
        state: >
          {% if this is defined %}
            {% if 'B7' in states('sensor.zyxel_cellular_intf_current_band') %}
              {{ this.state|int + 1 }}
            {% else %}
              {{ this.state }}
            {% endif %}
          {% else %}
            0
          {% endif %}

      - name: B1 Count
        state: >
          {% if this is defined %}
            {% if 'B1' in states('sensor.zyxel_cellular_intf_current_band') %}
              {{ this.state|int + 1 }}
            {% else %}
              {{ this.state }}
            {% endif %}
          {% else %}
            0
          {% endif %}

      - name:  etc...

Hellis81 · September 10, 2025, 11:33am

Would it not be possible to make this “dynamic” using the attributes?
Or is there something I’m missing?

tom_l · September 10, 2025, 11:49am

Don’t use attributes for values that change.

qm28jSLtTnkW · September 10, 2025, 4:01pm

Thank you @tom_l for the hint! It’s almost working, I say almost because when the main sensor state changes the count get incremented by 2:

after state changed like this

how could it be?!

d921 · September 10, 2025, 4:07pm

Do you mean this literally? Are attributes supposed to be de facto immutable descriptors of an entity?

qm28jSLtTnkW · September 10, 2025, 5:09pm

another case in which you could see that some template sensor get incremented by 2 and others never get incremented

tom_l · September 10, 2025, 9:21pm

Share your config.

Yes.

qm28jSLtTnkW · September 11, 2025, 8:42am

that’s in templates.yaml

  - name: "B7 Count"
    unique_id: "B7_count"
    state: >
      {% if this is defined %}
        {% if 'B7' in states('sensor.zyxel_cellular_intf_current_band') %}
          {{ this.state|int(0) + 1 }}
        {% else %}
          {{ this.state|int(0) }}
        {% endif %}
      {% else %}
        0
      {% endif %}
  - name: "B1 Count"
    unique_id: "B1_count"
    state: >
      {% if this is defined %}
        {% if 'B1' in states('sensor.zyxel_cellular_intf_current_band') %}
          {{ this.state|int(0) + 1 }}
        {% else %}
          {{ this.state|int(0) }}
        {% endif %}
      {% else %}
        0
      {% endif %}
  - name: "B3 Count"
    unique_id: "B3_count"
    state: >
      {% if this is defined %}
        {% if 'B3' in states('sensor.zyxel_cellular_intf_current_band') %}
          {{ this.state|int(0) + 1 }}
        {% else %}
          {{ this.state|int(0) }}
        {% endif %}
      {% else %}
        0
      {% endif %}
  - name: "B20 Count"
    unique_id: "B20_count"
    state: >
      {% if this is defined %}
        {% if 'B20' in states('sensor.zyxel_cellular_intf_current_band') %}
          {{ this.state|int(0) + 1 }}
        {% else %}
          {{ this.state|int(0) }}
        {% endif %}
      {% else %}
        0
      {% endif %}
  - name: "n78 Count"
    unique_id: "n78_count"
    state: >
      {% if this is defined %}
        {% if 'n78' in states('sensor.zyxel_cellular_intf_current_band') %}
          {{ this.state|int(0) + 1 }}
        {% else %}
          {{ this.state|int(0) }}
        {% endif %}
      {% else %}
        0
      {% endif %}

that’s my System Information

System Information

version	core-2025.9.1
installation_type	Home Assistant OS
dev	false
hassio	true
docker	true
container_arch	armv7
user	root
virtualenv	false
python_version	3.13.7
os_name	Linux
os_version	6.12.34-haos-raspi
arch	armv7l
timezone	Europe/Rome
config_dir	/config

Home Assistant Community Store

GitHub API	ok
GitHub Content	ok
GitHub Web	ok
HACS Data	ok
GitHub API Calls Remaining	5000
Installed Version	2.0.5
Stage	running
Available Repositories	2189
Downloaded Repositories	14

Solcast Solar

can_reach_server	ok

Home Assistant Cloud

logged_in	false
can_reach_cert_server	ok
can_reach_cloud_auth	ok
can_reach_cloud	ok

Home Assistant Supervisor

host_os	Home Assistant OS 16.2
update_channel	stable
supervisor_version	supervisor-2025.09.0
agent_version	1.7.2
docker_version	28.3.3
disk_total	57.8 GB
disk_used	4.5 GB
nameservers	192.168.1.54
healthy	true
supported	true
host_connectivity	true
supervisor_connectivity	true
ntp_synchronized	true
virtualization
board	rpi3
supervisor_api	ok
version_api	ok
installed_addons	File editor (5.8.0), Advanced SSH & Web Terminal (21.0.3), SQLite Web (4.4.0)

Dashboards

dashboards	5
resources	4
views	6
mode	storage

Recorder

oldest_recorder_run	August 27, 2025 at 06:17
current_recorder_run	September 10, 2025 at 09:25
estimated_db_size	543.46 MiB
database_engine	sqlite
database_version	3.48.0

what other parts of the configuration do you need ?

tom_l · September 11, 2025, 9:04am

You don’t need the filter here:

But it would not cause the issue and I have no idea how it is possible to increment by 2 given your config.

Let me “phone a friend” and I’ll get back to you (or they will).

tom_l · September 11, 2025, 9:16am

Actually, what is the state of your sensor here (hover your mouse to see):

Hellis81 · September 11, 2025, 9:19am

I can confirm something is wrong.

I was so interested in how or why that would happen that I added it to my config with an input text and it does double count.

template:
  - sensor:
    - name: "B7 Count"
      unique_id: "B7_count"
      state: >
        {% if this is defined %}
          {% if 'B7' in states('input_text.zyxel') %}
            {{ this.state|int(0) + 1 }}
          {% else %}
            {{ this.state|int(0) }}
          {% endif %}
        {% else %}
          0
        {% endif %}
    - name: "B1 Count"
      unique_id: "B1_count"
      state: >
        {% if this is defined %}
          {% if 'B1' in states('input_text.zyxel') %}
            {{ this.state|int(0) + 1 }}
          {% else %}
            {{ this.state|int(0) }}
          {% endif %}
        {% else %}
          0
        {% endif %}

qm28jSLtTnkW · September 11, 2025, 9:23am

color changed because I did a new query but the data it’s the same:

hope this’ll help

qm28jSLtTnkW · September 11, 2025, 9:25am

it’s also stranger (to me) that some sensors never get incremented…

Hellis81 · September 11, 2025, 9:28am

I think I understand why that is.
As far as my limited testing has shown if the state changes from
B3,B20,n78,B7 to B3,B20,n78,B7,B1 then it will not count up any of the values in the first set, only B1.
It seems it has to not be there, then be there for it to count. Which kind of makes sense.
Not sure if that is what you want but I believe that is the case

tom_l · September 11, 2025, 9:33am

Nope, any change of the sensor state will re-evaluate the templates.

qm28jSLtTnkW · September 11, 2025, 9:34am

that explains why some sensors didn’t get incremented at every state change.

Since I need to have a “statistical” representation of the most used bands over time, I don’t know how to consider the fact that some band will increment a lot just because they are swapped frequently (not because they are less used) and some will have lower numbers (because they are stable but also because they could be less used).

Still cannot grasp why the double increment at the same state change…

tom_l · September 11, 2025, 9:34am

No, it really doesn’t.

qm28jSLtTnkW · September 11, 2025, 9:40am

yes, I read your reply to @Hellis81 just after I clicked Reply on his post

Hellis81 · September 11, 2025, 9:58am

So this here should count B7 four times (or 8) right?

But in reality:

So it only counted it once (or 2 times) the other counts are from 32 minutes ago and is not the same session.

I agree that it should work the way you want it to, but it doesn’t