esphome/tests/unit_tests/fixtures/substitutions/02-expressions.input.yaml

substitutions:
  y: ${x}  # Circular reference, expect to pass unresolved.
  x: ${y}  # Circular reference, expect to pass unresolved.
  double_height: ${height * 2}
  width: 7
  height: 8
  enabled: true
  pin:
    number: 18
    inverted: true
  area: 25
  numberOne: 1
  var1: 79
  double_width: ${width * 2}
  c: ${b+1}
  b: ${undefined_variable | default(79) }

test_list:
  - "The area is ${width * height}"
  - ${width * height}
  - ${width * height} + 1
  - ${enabled and "ENABLED" or "DISABLED"}
  - list: ${ [width, height] }
  - "${ {'width': width, 'height': height} }"
  - ${pin}
  - The pin number is ${pin.number}
  - The square root is: ${math.sqrt(area)}
  - The number is ${var${numberOne} + 1}
  - ord("a") = ${ ord("a") }
  - chr(97) = ${ chr(97) }
  - len([1,2,3]) = ${ len([1,2,3]) }
  - width = ${width}, double_width = ${double_width}
  - a = ${a}