php 检查数组是否为空
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Check if array is empty
提问by user1684586
The following code shows an array of records in the $rowsarray from the MySQL query. I have added also an ifstatement to check if $rowsturns up empty, but it is not working.
以下代码显示了$rows来自 MySQL 查询的数组中的记录数组。我还添加了一个if语句来检查是否$rows为空，但它不起作用。
$rows = array();
$result1 = mysql_query("SELECT * FROM TestPhase where Pid<10", $db) or die("cannot select");
while($row = mysql_fetch_array($result1)) {
$rows []= array(
'id' => $row['id'],
'parent' => $row['parent'],
'name' => $row['name'],
);
}
if($rows == ""){
echo "No Data";
}
This ifstatement is not working. How do I check if the array returns empty and echo "No Data".
此if语句不起作用。如何检查数组是否返回空并回显“无数据”。
How would I check to see if the array is empty in javascript? I have placed the $rowsarray in a var treeData.
我将如何检查javascript中的数组是否为空？我已将$rows数组放在一个var treeData.
if (treeData) is empty{
$("button").hide();
}
How do I check if treeDatais empty to hide the button.
如何检查是否treeData为空以隐藏按钮。
回答by Havelock
PHP
Simply use empty(), i.e.
PHP
简单使用empty()，即
if(empty($rows)){
echo 'No Data';
}
Alternatively you could also use count(), i.e.
或者你也可以使用count()，即
if(count($rows) < 1){ // or if(count($rows) === 0)
echo 'No Data';
}
JavaScript
You can use the lengthproperty
JavaScript
您可以使用该length属性
if(treeData.length == 0){
$("button").hide();
}
回答by Muthu Kumaran
Use countto check
使用count来检查
if(!count($rows)){
echo "No Data";
}
Using JavaScript, here is the example
使用 JavaScript，这里是示例
var arr = new Array('one', 'two', 'three'); //assume you have list of values in array
if(!arr.length){ //if no array value exist, show alert()
alert('No Data');
}
回答by BenM
You can't treat an array like a string (i.e. $rows == ""). Use count()or empty()instead:
您不能将数组视为字符串（即$rows == ""）。使用count()或empty()代替：
if(count($rows) == 0)
{
echo "No Data";
}
回答by Gustav Barkefors
if ( count( $rows ) == 0 ) {...}
