PHP：如何通过sprintf（）添加前导零/零填充浮动？

I'm using sprintf() to get a formatted string of some float numbers with a certain precision. In addition, I wanted to add leading zeros to make all numbers even in length. Doing that for integers is pretty straight forward:

我正在使用sprintf()来获取具有一定精度的一些浮点数的格式化字符串。另外,我想添加前导零以使所有数字均匀。对整数执行此操作非常简单:

sprintf('%02d', 1);

This will result in 01. However, trying the same for a float with precision doesn't work:

这将导致01.但是,对具有精度的浮点尝试相同的操作不起作用:

sprintf('%02.2f', 1);

Yields 1.00.

How can I add leading zeros to a float value?

如何将前导零添加到浮点值?

1 个解决方案

#1

Short answer: sprintf('%05.2f', 1); will give the desired result 01.00

简答:sprintf('%05.2f',1);将给出所需的结果01.00

Note how %02 was replaced by %05.

请注意%02如何被%05取代。

Explanation

This forum post pointed me in the right direction: The first number does neither denote the number of leading zeros nor the number of total charaters to the left of the decimal seperator but the total number of characters in the resulting string!

这个论坛帖子向我指出了正确的方向:第一个数字既不表示前导零的数量,也不表示小数分隔符左侧的总字符数,而是结果字符串中的字符总数!

Example

sprintf('%02.2f', 1); yields at least the decimal seperator "." plus at least 2 characters for the precision. Since that is already 3 characters in total, the %02 in the beginning has no effect. To get the desired "2 leading zeros" one needs to add the 3 characters for precision and decimal seperator, making it sprintf('%05.2f', 1);

sprintf('%02.2f',1);产生至少十进制分隔符“。”加上至少2个字符的精度。由于总共已有3个字符,因此开头的%02无效。要获得所需的“2前导零”,需要为精度和小数分隔符添加3个字符,使其成为sprintf('%05.2f',1);

Some code

$num = 42.0815;

function printFloatWithLeadingZeros($num, $precision = 2, $leadingZeros = 0){
    $decimalSeperator = ".";
    $adjustedLeadingZeros = $leadingZeros + mb_strlen($decimalSeperator) + $precision;
    $pattern = "%0{$adjustedLeadingZeros}{$decimalSeperator}{$precision}f";
    return sprintf($pattern,$num);
}

for($i = 0; $i <= 6; $i++){
    echo "$i max. leading zeros on $num = ".printFloatWithLeadingZeros($num,2,$i)."\n";
}

Output

0 max. leading zeros on 42.0815 = 42.08
1 max. leading zeros on 42.0815 = 42.08
2 max. leading zeros on 42.0815 = 42.08
3 max. leading zeros on 42.0815 = 042.08
4 max. leading zeros on 42.0815 = 0042.08
5 max. leading zeros on 42.0815 = 00042.08
6 max. leading zeros on 42.0815 = 000042.08

1 个解决方案

#1

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