Blockly.Python[''] = function()

in generators/python/math.js [240:334]
87 lines of code
10 McCabe index (conditional complexity)

Blockly.Python['math_on_list'] = function(block) {
  // Math functions for lists.
  var func = block.getFieldValue('OP');
  var list = Blockly.Python.valueToCode(block, 'LIST',
      Blockly.Python.ORDER_NONE) || '[]';
  var code;
  switch (func) {
    case 'SUM':
      code = 'sum(' + list + ')';
      break;
    case 'MIN':
      code = 'min(' + list + ')';
      break;
    case 'MAX':
      code = 'max(' + list + ')';
      break;
    case 'AVERAGE':
      Blockly.Python.definitions_['from_numbers_import_Number'] =
          'from numbers import Number';
      var functionName = Blockly.Python.provideFunction_(
          'math_mean',
          // This operation excludes null and values that aren't int or float:',
          // math_mean([null, null, "aString", 1, 9]) == 5.0.',
          ['def ' + Blockly.Python.FUNCTION_NAME_PLACEHOLDER_ + '(myList):',
           '  localList = [e for e in myList if isinstance(e, Number)]',
           '  if not localList: return',
           '  return float(sum(localList)) / len(localList)']);
      code = functionName + '(' + list + ')';
      break;
    case 'MEDIAN':
      Blockly.Python.definitions_['from_numbers_import_Number'] =
          'from numbers import Number';
      var functionName = Blockly.Python.provideFunction_(
          'math_median',
          // This operation excludes null values:
          // math_median([null, null, 1, 3]) == 2.0.
          ['def ' + Blockly.Python.FUNCTION_NAME_PLACEHOLDER_ + '(myList):',
           '  localList = sorted([e for e in myList if isinstance(e, Number)])',
           '  if not localList: return',
           '  if len(localList) % 2 == 0:',
           '    return (localList[len(localList) // 2 - 1] + ' +
               'localList[len(localList) // 2]) / 2.0',
           '  else:',
           '    return localList[(len(localList) - 1) // 2]']);
      code = functionName + '(' + list + ')';
      break;
    case 'MODE':
      var functionName = Blockly.Python.provideFunction_(
          'math_modes',
          // As a list of numbers can contain more than one mode,
          // the returned result is provided as an array.
          // Mode of [3, 'x', 'x', 1, 1, 2, '3'] -> ['x', 1].
          ['def ' + Blockly.Python.FUNCTION_NAME_PLACEHOLDER_ + '(some_list):',
           '  modes = []',
           '  # Using a lists of [item, count] to keep count rather than dict',
           '  # to avoid "unhashable" errors when the counted item is ' +
               'itself a list or dict.',
           '  counts = []',
           '  maxCount = 1',
           '  for item in some_list:',
           '    found = False',
           '    for count in counts:',
           '      if count[0] == item:',
           '        count[1] += 1',
           '        maxCount = max(maxCount, count[1])',
           '        found = True',
           '    if not found:',
           '      counts.append([item, 1])',
           '  for counted_item, item_count in counts:',
           '    if item_count == maxCount:',
           '      modes.append(counted_item)',
           '  return modes']);
      code = functionName + '(' + list + ')';
      break;
    case 'STD_DEV':
      Blockly.Python.definitions_['import_math'] = 'import math';
      var functionName = Blockly.Python.provideFunction_(
          'math_standard_deviation',
          ['def ' + Blockly.Python.FUNCTION_NAME_PLACEHOLDER_ + '(numbers):',
           '  n = len(numbers)',
           '  if n == 0: return',
           '  mean = float(sum(numbers)) / n',
           '  variance = sum((x - mean) ** 2 for x in numbers) / n',
           '  return math.sqrt(variance)']);
      code = functionName + '(' + list + ')';
      break;
    case 'RANDOM':
      Blockly.Python.definitions_['import_random'] = 'import random';
      code = 'random.choice(' + list + ')';
      break;
    default:
      throw Error('Unknown operator: ' + func);
  }
  return [code, Blockly.Python.ORDER_FUNCTION_CALL];
};