如果我使用Echo，则三元操作员无效

Question

我正在使用此三元运算符：

$this->checkIfProductCategoriesContainsString($productId, $categoryNeedle) !== false ? echo "Category containing categoryNeedle exists" : echo "Category does not exist.";

我也这样尝试：

($this->checkIfProductCategoriesContainsString($productId, $categoryNeedle) !== false) ? echo "Category containing categoryNeedle exists" : echo "Category does not exist.";

但我的IDE说unexpected echo after ?

Answer 1

呢

echo(
    $this->checkIfProductCategoriesContainsString($productId, $categoryNeedle) !== false
        ? "Category containing categoryNeedle exists"
        : "Category does not exist."
);

Answer 2

您应该在PHP中阅读有关print和echo之间的差异。tl; dr使用打印。

$this->checkIfProductCategoriesContainsString($productId, $categoryNeedle) ?
    print "Category containing category needle exists" : 
    print "Category does not exist.";

，但最好只有：

echo $this->checkIfProductCategoriesContainsString($productId, $categoryNeedle) ?
    'Category containing category needle exists' : 
    'Category does not exist.';