PHP關於數據的舍入歸類：round、ceil、floor、number_format

下面是關於數字轉化的幾種方法：

round -- 對浮點數進行四捨五入

例子：

<?php
echo round(3.4);         // 3

echo round(3.6);         // 4

echo round(3.6, 0);      // 4

echo round(1.95583, 2);  // 1.96

echo round(1241757, -3); // 1242000

echo round(5.055, 2);    // 5.06

?>

ceil -- 進一法取整

例子：

<?php
echo ceil(4.3);    // 5

echo ceil(9.999);  // 10

?>

floor -- 捨去法取整，跟ceil剛剛相反

例子：

<?php
echo floor(4.3);   // 4

echo floor(9.999); // 9
?>

number_format -- 格式化數字爲千分位

<?php

$number = 1234;

// english notation (default)
$english_format_number = number_format($number);
echo "First:".$english_format_number."<br />";

// French notation
$nombre_format_francais = number_format($number, 2, ',', ' ');
echo "Second:".$nombre_format_francais."<br />";

// French notation
$number = 1234.564;
$nombre_format_francais = number_format($number, 2, ',', ' ');
echo "Third:".$nombre_format_francais."<br />";

$number = 1234.5678;

// english notation without thousands seperator
$english_format_number = number_format($number, 2, '.', '');
echo "Forth:".$english_format_number."<br />";

?>

顯示結果最終以下： First:1,234 Second:1234,00 Third:1234,56 Forth:1234.57