Question

只是想知道为什么我的代码不在这里工作：

<?php
    session_start();
    if (isset($_SESSION)) {
      session_unset();
      session_destroy();
    }
?>

我尝试打印出echo isset（$ _ SESSION）的结果并返回true，而我需要登录的页面仍允许我访问它们。

Answer 1

您必须明确将变量定义为会话

例如：

<强> LOGIN

<?php
    session_start();
    if($_POST['LOGOUT']=='exit'){
@session_unset();
    }
    ?>

<强> LOGOUT

let array = [
    "0000000000000000000",
    "0000001110000000000",
    "0000011111000000000",
    "0000001110000000000",
    "0000000000000000000",
    "0001100000000000000",
    "0001100000000011000",
    "0011100000000011000",
    "0000000000000000000"
]

// A structure to hold the cell's coordinate as Int array
// can become confusing very quickly
struct Cell: Equatable {
    var row: Int
    var column: Int
    var clusterIndex: Int?

    static func == (lhs: Cell, rhs: Cell) -> Bool {
        return lhs.row == rhs.row && lhs.column == rhs.column
    }
}

// Get all the "1" cells
var cells = array.enumerated().flatMap { arg -> [Cell] in
    let (rowIndex, str) = arg

    // The flatMap below will become compactMap in Swift 4.1
    return str.enumerated().flatMap { colIndex, char in
        if char == "1" {
            return Cell(row: rowIndex, column: colIndex, clusterIndex: nil)
        } else {
            return nil
        }
    }
}

// Assign each cell a clusterIndex
for (i, currentCell) in cells.enumerated() {

    // A cell may not have all four neighbors, or not all its
    // neighbors are "1" cells, hence the "potential"
    let potentialNeighbors = [
        Cell(row: currentCell.row - 1, column: currentCell.column, clusterIndex: nil), // above
        Cell(row: currentCell.row + 1, column: currentCell.column, clusterIndex: nil), // below
        Cell(row: currentCell.row, column: currentCell.column - 1, clusterIndex: nil), // left
        Cell(row: currentCell.row, column: currentCell.column + 1, clusterIndex: nil)  // right
    ]

    // Get the actual neighboring cells and their indexes
    let neighborsAndIndexes = cells.enumerated().filter { arg in
        let (_, c) = arg
        return potentialNeighbors.contains(c)
    }
    let neighborIndexes = neighborsAndIndexes.map { $0.0 }
    let neighbors = neighborsAndIndexes.map { $0.1 }

    // Determine what clusterIndex we should give the current cell and its neighbors
    var clusterIndex = 0

    if currentCell.clusterIndex != nil {
        // If the current cell already has a clusteredIndex, reuse it
        clusterIndex = currentCell.clusterIndex!
    } else if let neighborClusterIndex = neighbors.first(where: { $0.clusterIndex != nil })?.clusterIndex {
        // If the current cell has a neighbor whose clusterIndex is not nil, use that
        clusterIndex = neighborClusterIndex
    } else {
        // Else increment from the max existing clusterIndex
        clusterIndex = (cells.map({ $0.clusterIndex ?? 0 }).max() ?? 0) + 1
    }

    // Assign the same clusterIndex to the current cell and its neighbors
    ([i] + neighborIndexes).forEach {
        cells[$0].clusterIndex = clusterIndex
    }
}

// Group the cells by their clusterIndex
let clusters = Dictionary(grouping: cells, by: { $0.clusterIndex! })
    .sorted(by: { $0.key < $1.key })
    .map { $0.value }

// Print the result
// Visualize which cell belong to which cluster and how it appears on the board
for i in 0..<array.count {
    for j in 0..<array[0].count {
        if let clusterIndex = cells.first(where: { $0.row == i && $0.column == j })?.clusterIndex {
            print(clusterIndex, terminator: "")
        } else {
            print("-", terminator: "")
        }
    }
    print() // print a newline
}

您也可以使用未设置（$ _ SESSION [＆＃39;用户名＆＃39;]）; 代替 session_unset（）;

Session_unset和session_destroy不起作用

1 个答案: