Question

嗨，我正在尝试在JS中创建一个函数，该函数接受字符串并检查字符串中是否有相等数量的“ x”和“ o”。

到目前为止，我的代码（无法正常工作）：

var vector = new Point(10, 10);

// Create path.
var path = new Path({
    segments: [
        [100, 100],
        [200, 100],
        [260, 170],
        [360, 170],
        [420, 250]
    ],
    strokeColor: 'red',
    strokeWidth: 10
});

// Translate given thing along global vector.
function translateThing(thing) {
    switch (thing.getClassName()) {
        case 'Path':
            thing.position += vector;
            break;
        case 'Curve':
            thing.segment1.point += vector;
            thing.segment2.point += vector;
            break;
        case 'Segment':
            thing.point += vector;
            break;
    }
}

// On mouse down...
function onMouseDown(event) {
    // ...only select what was clicked.
    path.selected = false;
    hit = paper.project.hitTest(event.point);
    if (hit && hit.location) {
        hit.location.curve.selected = true;
    }
    else if (hit && hit.segment) {
        hit.segment.selected = true;
    }

    // We check all items for demo purpose.
    // Move all selected things.
    // First get selected items in active layer...
    project.activeLayer.getItems({ selected: true })
    // ...then map them to what is really selected...
    .map(getSelectedThing)
    // ...then translate them.
    .forEach(translateThing);
}

// This method returns what is really selected in a given item.
// Here we assume that only one thing can be selected at the same time.
// Returned thing can be either a Curve, a Segment or an Item.
function getSelectedThing(item) {
    // Only check curves and segments if item is a path.
    if (item.getClassName() === 'Path') {
        // Check curves.
        for (var i = 0, l = item.curves.length; i < l; i++) {
            if (item.curves[i].selected) {
                return item.curves[i];
            }
        }
        // Check segments.
        for (var i = 0, l = item.segments.length; i < l; i++) {
            if (item.segments[i].selected) {
                return item.segments[i];
            }
        }
    }
    // return item by default.
    return item;
}

Answer 1

const定义了一个常量，因此您将无法更改y和z的值。相反，您应该使用var或let：

let y = 0;
let z = 0;

Answer 2

考虑以“功能性”方式进行操作：

const checkXo = (str, a, b) =>
  str.split('').filter(s => s === a).length ===
    str.split('').filter(s => s === b).length

使用

进行测试

checkXo('xxoo', 'x', 'o')    // return true
checkXo('stackoverflow', 'x', 'o')  // return false

请注意，单行代码可以检查相同数量的所选字符“ a，b”。

检查字符串中是否有相等数量的2个字符

2 个答案: