题
以下磁力龙驱动了我坚果。在地球100x上可以等于100,然后100x被报告为整数?
在我的生活中,我无法弄清楚。
你可以复制和粘贴整个东西,为自己看。
我在这里的某个地方错过了一个简单的一点,帮助我出去伙计们。
function blp_int($val) {
$orgval = $val;
$num = (int)$val;
echo "<li><font color=red>val: ". $val . " is being checked to see if it's an integer or not";
echo "<li><font color=red>orgval: ". $orgval ;
echo "<li><font color=red>num: ". $num ;
if ($orgval==$num) {
echo "<li><font color=red><b>YES IT IS! the [{$orgval}] is equal to [{$num}]</b>";
return true;
}
return false;
}
if (blp_int("100"))
{
echo "<h1>100 is an integer!</h1>";
}
else
{
echo "<h1>100 is NOT an integer!</h1>";
}
if (blp_int("100x"))
{
echo "<h1>100x is an integer!</h1>";
}
else
{
echo "<h1>100x is NOT an integer!</h1>";
}
.
上面的代码,当运行返回以下时;
val: 100 is being checked to see if it's an integer or not
orgval: 100
num: 100
YES IT IS. the [100] is equal to [100]
100 is an integer!
val: 100x is being checked to see if it's an integer or not
orgval: 100x
num: 100
YES IT IS. the [100x] is equal to [100]
100x is an integer!
.
我可以通过添加以下位来弥补情况
if (!is_numeric($val))
{
return false;
}
.
在blp_int函数的顶部,只要在蝙蝠,但是,我仍然非常好奇地发现为什么在地球php上认为100x= 100等于。
解决方案
As you can see in this example, casting 100x
as an integer converts it to 100
. Since you are not using strict comparison, '100x' == 100
is true. PHP removes the x
from it to make just 100
.
You could use strict comparison (which also compares the types), such that '100x' === 100
would return false. Using it, any time a string was compared to an integer, it would return false.
As per your edit: is_numeric
may not be the most reliable, as it will return true for numbers formatted as a string, such as '100'
. If you want the number to be an integer (and never a string), you could use is_integer
instead. I'm not quite sure what exactly you're doing, but i thought I'd add this note.
其他提示
I think you should use three equal signs in your IF:
if ($orgval===$num) {
Otherwise PHP casts the value 100x
to 100
and 100=100
.
What kind of check do you want to do? There are a few ways you could go about it:
if (preg_match('!^[0-9]+$!', $input))
if (intval($input) == $input)
if (intval($input) === $input)
if ('x'.intval($input) === 'x'.$input)
It depends on how closely you want to check if it's an integer. Does it matter if you need to trim()
it first?
Either cast it to an int
or try http://php.net/manual/en/function.ctype-digit.php. You also need ===
in your if.