in generators/dart/math.js [254:418]
Blockly.Dart['math_on_list'] = function(block) {
// Math functions for lists.
var func = block.getFieldValue('OP');
var list = Blockly.Dart.valueToCode(block, 'LIST',
Blockly.Dart.ORDER_NONE) || '[]';
var code;
switch (func) {
case 'SUM':
var functionName = Blockly.Dart.provideFunction_(
'math_sum',
['num ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
'(List<num> myList) {',
' num sumVal = 0;',
' myList.forEach((num entry) {sumVal += entry;});',
' return sumVal;',
'}']);
code = functionName + '(' + list + ')';
break;
case 'MIN':
Blockly.Dart.definitions_['import_dart_math'] =
'import \'dart:math\' as Math;';
var functionName = Blockly.Dart.provideFunction_(
'math_min',
['num ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
'(List<num> myList) {',
' if (myList.isEmpty) return null;',
' num minVal = myList[0];',
' myList.forEach((num entry) ' +
'{minVal = Math.min(minVal, entry);});',
' return minVal;',
'}']);
code = functionName + '(' + list + ')';
break;
case 'MAX':
Blockly.Dart.definitions_['import_dart_math'] =
'import \'dart:math\' as Math;';
var functionName = Blockly.Dart.provideFunction_(
'math_max',
['num ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
'(List<num> myList) {',
' if (myList.isEmpty) return null;',
' num maxVal = myList[0];',
' myList.forEach((num entry) ' +
'{maxVal = Math.max(maxVal, entry);});',
' return maxVal;',
'}']);
code = functionName + '(' + list + ')';
break;
case 'AVERAGE':
// This operation exclude null and values that are not int or float:
// math_mean([null,null,"aString",1,9]) == 5.0.
var functionName = Blockly.Dart.provideFunction_(
'math_mean',
['num ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
'(List myList) {',
' // First filter list for numbers only.',
' List localList = new List.from(myList);',
' localList.removeWhere((a) => a is! num);',
' if (localList.isEmpty) return null;',
' num sumVal = 0;',
' localList.forEach((var entry) {sumVal += entry;});',
' return sumVal / localList.length;',
'}']);
code = functionName + '(' + list + ')';
break;
case 'MEDIAN':
var functionName = Blockly.Dart.provideFunction_(
'math_median',
['num ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
'(List myList) {',
' // First filter list for numbers only, then sort, ' +
'then return middle value',
' // or the average of two middle values if list has an ' +
'even number of elements.',
' List localList = new List.from(myList);',
' localList.removeWhere((a) => a is! num);',
' if (localList.isEmpty) return null;',
' localList.sort((a, b) => (a - b));',
' int index = localList.length ~/ 2;',
' if (localList.length % 2 == 1) {',
' return localList[index];',
' } else {',
' return (localList[index - 1] + localList[index]) / 2;',
' }',
'}']);
code = functionName + '(' + list + ')';
break;
case 'MODE':
Blockly.Dart.definitions_['import_dart_math'] =
'import \'dart:math\' as Math;';
// 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].
var functionName = Blockly.Dart.provideFunction_(
'math_modes',
['List ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
'(List values) {',
' List modes = [];',
' List counts = [];',
' int maxCount = 0;',
' for (int i = 0; i < values.length; i++) {',
' var value = values[i];',
' bool found = false;',
' int thisCount;',
' for (int j = 0; j < counts.length; j++) {',
' if (counts[j][0] == value) {',
' thisCount = ++counts[j][1];',
' found = true;',
' break;',
' }',
' }',
' if (!found) {',
' counts.add([value, 1]);',
' thisCount = 1;',
' }',
' maxCount = Math.max(thisCount, maxCount);',
' }',
' for (int j = 0; j < counts.length; j++) {',
' if (counts[j][1] == maxCount) {',
' modes.add(counts[j][0]);',
' }',
' }',
' return modes;',
'}']);
code = functionName + '(' + list + ')';
break;
case 'STD_DEV':
Blockly.Dart.definitions_['import_dart_math'] =
'import \'dart:math\' as Math;';
var functionName = Blockly.Dart.provideFunction_(
'math_standard_deviation',
['num ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
'(List myList) {',
' // First filter list for numbers only.',
' List numbers = new List.from(myList);',
' numbers.removeWhere((a) => a is! num);',
' if (numbers.isEmpty) return null;',
' num n = numbers.length;',
' num sum = 0;',
' numbers.forEach((x) => sum += x);',
' num mean = sum / n;',
' num sumSquare = 0;',
' numbers.forEach((x) => sumSquare += ' +
'Math.pow(x - mean, 2));',
' return Math.sqrt(sumSquare / n);',
'}']);
code = functionName + '(' + list + ')';
break;
case 'RANDOM':
Blockly.Dart.definitions_['import_dart_math'] =
'import \'dart:math\' as Math;';
var functionName = Blockly.Dart.provideFunction_(
'math_random_item',
['dynamic ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
'(List myList) {',
' int x = new Math.Random().nextInt(myList.length);',
' return myList[x];',
'}']);
code = functionName + '(' + list + ')';
break;
default:
throw Error('Unknown operator: ' + func);
}
return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
};