doze79040
2019-07-07 19:05
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PHP如果for循环中的条件具有浮点数[duplicate]

This question already has an answer here:

An if condition in a for loop would stop working after (n) times.

I'm using PHP 7.3.6-1+ubuntu18.04.1+deb.sury.org+1

Given the following code:

for($i = 0.99; $i<= 30.99; $i++){
    echo $i;
    if($i == 10.99){
        echo '<--- selected';
    }
    echo '<br>';
}

output

0.99
1.99
2.99
3.99
4.99
5.99
6.99
7.99
8.99
9.99
10.99<--- selected
11.99
12.99
13.99
14.99
15.99
16.99
17.99
18.99
19.99
20.99
21.99
22.99
23.99
24.99
25.99
26.99
27.99
28.99
29.99

This remain true when the condition is between 0.99 - 15.99, However, changing the condition between 16.99 - 29.99, <--- selected is not returned.

I ran few tests using int in my loop as shown below and it seems to work fine.

for($i = 0; $i<= 30; $i++){
    echo $i;
    if($i == 18){
        echo '<--- selected';
    }
    echo '<br>';
}

I think the problem is related to this float (0.99 - 30.99).

</div>
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2条回答 默认 最新

  • drh37116 2019-07-07 19:14
    最佳回答

    A possible solution is to make the numbers string and that way compare them.
    Using "10.99" on one side and number_format on the other

    for($i = 0.99; $i<= 30.99; $i++){
        echo $i;
        if(number_format($i,2) == "22.99"){
            echo '<--- selected';
        }
        echo "
    ";
    }
    

    https://3v4l.org/mvOR3

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