Question

我在nodejs应用程序中使用以下代码，从构成邻接列表的数据库行数组构建树：

// Lay out every node in the tree in one flat array.
var flatTree = [];
_.each(rows, function(row) {
    flatTree.push(row);
});

// For each node, find its parent and add it to that parent's children.
_.each(rows, function(row) {
    // var parent = _.find(flatTree, function(p) {
    //     p.Id == row.ParentId;
    // });
    var parent;
    for (var i = 0; i < flatTree.length; i++){
        if (flatTree[i].Id == row.ParentId) {
            parent = flatTree[i];
            break;
        }
    };
    if (parent){
        if (!parent.subItems) {
            parent.subItems = [];
        };
        parent.subItems.push(row);
    }
});

我希望注释掉的_.find调用与它下面的解决方法for循环完全相同，但是_.find永远不会在{{1}中找到父节点} {} flatTree循环始终如此。

同样，对for的调用也不起作用，而替代循环也是如此：

_.filter

我使用的是// var rootItems = _.filter(flatTree, function (node) { // //node.ParentId === null; // node.NoParent === 1; // }) var rootItems = []; for (var i = 0; i < flatTree.length; i++){ if (flatTree[i].ParentId == null){ rootItems.push(flatTree[i]); } }软件包，但已尝试使用常规underscore-node软件包获得相同的结果。

Answer 1

错过了library(car) # tests if the coefficient of Sepal.Width = Petal.Length linearHypothesis(model, "Sepal.Width = Petal.Length") Linear hypothesis test Hypothesis: Sepal.Width - Petal.Length = 0 Model 1: restricted model Model 2: Sepal.Length ~ Sepal.Width + Petal.Length Res.Df RSS Df Sum of Sq F Pr(>F) 1 148 16.744 2 147 16.329 1 0.4157 3.7423 0.05497 . --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 # Other examples: # tests if the coefficient of Sepal.Width = 0 linearHypothesis(model, "Sepal.Width = 0") # tests if the coefficient of Sepal.Width = 0.5 linearHypothesis(model, "Sepal.Width = 0.5") # tests if both are equal to zero linearHypothesis(model, c("Sepal.Width = 0", "Petal.Length = 0"))。

return

在您的代码中，不会返回任何内容，因此默认情况下会返回var parent = _.find(flatTree, function(p) { return p.Id == row.ParentId; // Return true if the ID matches ^^^^^^ <-- This });，undefined将不包含任何数据。

Underscorejs＆＃39;发现＆＃39;没有按预期工作

1 个答案: