.allElementsSameLength

檢查是否所有元素 (一列資料) 都等長。

⭐️ 注意：這是 Collection 的擴展，不是 Array 的。

🌀 Collection

💾 程式： replit

// extension primarily for array of arrays
extension Collection where Element: Collection {
    /// all elements (rows) are of the some length
    /// - `[[1,2], [3,4]].allElementsSameLength == true`
    public var allElementsSameLength: Bool {
        guard !isEmpty else { return true }
        return dropFirst().allSatisfy { $0.count == first!.count }
    }
}

💈範例

💾 程式： replit

public func testArray_allElementsSameLength() {

    // array of arrays
    let data = [
        ["labe", "value", "type"],
        ["name", "joe", "String"],
        ["age", "8", "Int"]
    ]

    let data2 = [
        ["labe", "value", "type"],
        ["name", "joe"],
        ["age", "8", "Int"]
    ]

    let data3 = [[1,1], [3,4]]
    let data4 = [[1,2,3]]            // one row only
    let data5 = [[Int]]()            // no row
    
    // print results
    let items: [HasMirrors] = [
        data.allElementsSameLength,     // T
        data2.allElementsSameLength,    // F
        data3.allElementsSameLength,    // T
        data4.allElementsSameLength,    // T
        data5.allElementsSameLength,    // T
    ]
    
    items.log()
}

Result:

// ✅
// ❌
// ✅
// ✅
// ✅

📘 手冊

• Swift ⟩ Sequence and Collection Protocols ⟩ Collection

  • Array ⟩ allSatisfy(_:)

🗣 討論

• Adding Array extension for multidimensional arrays in swift?

👥 相關

• is an extension for Collections.

• similar to arr.allElementsEqual.