本文介绍了负(负)零等于PHP中的0吗?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一个非常基本的MySQL查询,该查询从数据库表中读取行,并将行值添加到定义为$ total_balance的PHP字符串中.
例如;
$statement_details_query = mysqli_query($con,"SELECT transaction_nominal_code, SUM(transaction_debit) as TotalDebit, SUM(transaction_credit) as TotalCredit FROM accounts_transaction GROUP BY transaction_nominal_code") or die(mysql_error());
while($statement_details = mysqli_fetch_array( $statement_details_query )) {
$balance = $statement_details['TotalCredit'] - $statement_details['TotalDebit'];
$total_balance = $total_balance + $balance;
}
echo number_format($total_balance, 2, '.', ',');
我的问题是-0和0之间有什么区别?
解决方案
在PHP中,没有真正的区别:
浮动:
php > $negZ = -0.0;
php > $posZ = +0.0;
php > var_dump($negZ == $posZ, $negZ === $posZ);
bool(true)
bool(true)
Int:
php > $negZ = -0;
php > $posZ = +0;
php > var_dump($negZ == $posZ, $negZ === $posZ);
bool(true)
bool(true)
I have a very basic MySQL query that reads rows from a database table and adds or subtracts the row value to a PHP string defined as $total_balance.
For example;
$statement_details_query = mysqli_query($con,"SELECT transaction_nominal_code, SUM(transaction_debit) as TotalDebit, SUM(transaction_credit) as TotalCredit FROM accounts_transaction GROUP BY transaction_nominal_code") or die(mysql_error());
while($statement_details = mysqli_fetch_array( $statement_details_query )) {
$balance = $statement_details['TotalCredit'] - $statement_details['TotalDebit'];
$total_balance = $total_balance + $balance;
}
echo number_format($total_balance, 2, '.', ',');
My question is, what is the difference between -0 and 0?
解决方案
In PHP, there is no real difference:
Float:
php > $negZ = -0.0;
php > $posZ = +0.0;
php > var_dump($negZ == $posZ, $negZ === $posZ);
bool(true)
bool(true)
Int:
php > $negZ = -0;
php > $posZ = +0;
php > var_dump($negZ == $posZ, $negZ === $posZ);
bool(true)
bool(true)
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