Converting a string to datetime in python

1

as imports are not allowed - ho do i do this? need to substract a datetime from another represented by string

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2

To help you, you would need to tell us more about where you need this datetime conversion - Python Script, a custom component, maybe in a template (sensor)?
Also, it often helps if you could show us what you have already tried, for example configuration or code snippets (working or not).

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3

take a look at the subject :slight_smile: - it’s python
i have a string saved in var to keep current time for later comparison:

- service: var.set
  data_template:
    entity_id: var.ac1_fan_measure_start_time
    value_template: "{{as_timestamp(states.sensor.time.last_changed)}}"

but when i use it from python - it is recognized as a string

now = hass.states.get('sensor.time').last_changed
measureStartTime = hass.states.get('var.ac1_fan_measure_start_time').state

i need to get the time diff between the two

4

Yeah, I read the subject, but couldn’t think of a place where you would use plain Python without the ability to import anything.

Since you insist that you are using Python, and I can see that you somehow got hold of the hass object, I don’t see any reason why you should not also be able to import, for example:

from homeassistant.util import dt as dt_util

dt_util.utc_from_timestamp(float(measureStartTime))
5

I believe you mean this code is running in a HA python_script, which indeed has a limited execution environment.

First, you’re not saving a datetime. You’ve first converted it to a timestamp, which is a number. And, of course, like the state of all entities in HA, no matter what type it starts as, it will be converted to a string.

I would suggest:

now = hass.states.get('sensor.time').last_changed.timestamp()
measureStartTime = float(hass.states.get('var.ac1_fan_measure_start_time').state)
delta = now - measureStartTime
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6

python script (ac =1):

  now = hass.states.get('sensor.time').last_changed.timestamp
  measureStartTime = float(hass.states.get('var.ac%s_fan_measure_start_time' %(ac)).state)
  logger.info('LSX: now=%s start=%s', now, measureStartTime)
  diff = now - measureStartTime
  logger.info('LSX: diff=%s', now)

this is the output of the log:

now=<built-in method timestamp of datetime.datetime object at 0x6d203f80> start=1570687681.015453
Error executing script: unsupported operand type(s) for -: 'builtin_function_or_method' and 'float'
7

Because you didn’t copy the code correctly. You missed the parentheses for the timestamp function.

1 Like
8

sorry - fixed it and working now - great thx!

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