php 字符串中的零填充数字
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Zero-pad digits in string
提问by Konrad Rudolph
I need to cast single figures (1 to 9) to (01 to 09). I can think of a way but its big and ugly and cumbersome. I'm sure there must be some concise way. Any Suggestions
我需要将单个数字（1 到 9）转换为（01 到 09）。我能想到一种方法，但它又大又丑又笨重。我确定必须有一些简洁的方法。有什么建议
回答by Konrad Rudolph
First of all, your description is misleading. Doubleis a floating point data type. You presumably want to pad your digits with leading zeros in a string. The following code does that:
首先，你的描述有误导性。Double是浮点数据类型。您大概想用字符串中的前导零填充数字。以下代码执行此操作：
$s = sprintf('%02d', $digit);
For more information, refer to the documentation of sprintf.
有关更多信息，请参阅sprintf.
回答by LeppyR64
回答by Alex
Solution using str_pad:
使用str_pad 的解决方案：
str_pad($digit,2,'0',STR_PAD_LEFT);
Benchmark on php 5.3
php 5.3 基准测试
Result str_pad : 0.286863088608
Result sprintf : 0.234171152115
结果 str_pad : 0.286863088608
结果 sprintf : 0.234171152115
Code:
代码：
$start = microtime(true);
for ($i=0;$i<100000;$i++) {
str_pad(9,2,'0',STR_PAD_LEFT);
str_pad(15,2,'0',STR_PAD_LEFT);
str_pad(100,2,'0',STR_PAD_LEFT);
}
$end = microtime(true);
echo "Result str_pad : ",($end-$start),"\n";
$start = microtime(true);
for ($i=0;$i<100000;$i++) {
sprintf("%02d", 9);
sprintf("%02d", 15);
sprintf("%02d", 100);
}
$end = microtime(true);
echo "Result sprintf : ",($end-$start),"\n";
