I’m working on a YAML config file for ESPHome and need to use some anchors to avoid a lot of repetition. I’ve been having a really tough time finding information on YAML anchors and examples of more than just the simplest uses. In this case, I have, with someone’s suggestion:

.number: &AnchorDelay
optimistic: true
min_value: 0
max_value: 600
step: 1
initial_value: 0
web_server: &AnchorDelayWebServer
  sorting_group_id: sorting_group_switchmain
  sorting_weight: 30

number:
  - platform: template
    <<: *AnchorDelay
    id: "SwitchMainDelay"
    name: "Main Switch Delay"

  - platform: template
    <<: *AnchorDelay
    id: "Switch01Delay"
    name: "Switch 01 Delay"
    web_server:
      << : *AnchorDelayWebServer
      sorting_group_id: sorting_group_switch1

In order to create the original component I wanted within the number: section, this format has been the only thing I could find. It seems to work, but I can’t find clear documentation on what the .number with the dot/period at the start of the line does. I’ve searched and have not found any clear answer of just what that’s about or what it does.