如何結合PHP 的log10 函數與number_format 格式化輸出計算結果？

gitbox 2025-09-23

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</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h1>如何結合 PHP 的 log10 函數與 number_format 格式化輸出計算結果？</h1>"</span></span><span>;

</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<p>在 PHP 中，如果我們想對一個數字進行以 10 為底的對數計算，並且希望將結果以更加易讀的格式輸出，可以結合 <code>log10()

"; echo "

2. number_format() 函數簡介

" ; echo "

number_format()用於格式化數字，通常用於控制小數位數、添加千位分隔符等。例如：

" ; echo "

\$value = 12345.6789;
echo number_format(\$value, 2); // 輸出12,345.68

" ; echo "

3. 結合log10 與number_format

" ; echo "

假設我們要計算一個數字的log10，並且希望輸出保留2 位小數，格式化後更易讀：

" ; echo "

\$num = 98765;
\$logResult = log10(\$num); // 計算以10 為底的對數\$formatted = number_format(\$logResult, 2); // 保留2 位小數並格式化echo \$formatted; // 輸出結果例如4.99

" ; echo "

4. 完整示例代碼

" ; echo "

\$numbers = [10, 100, 1000, 12345];

foreach (\$numbers as \$n) {
    \$logVal = log10(\$n);
    echo &#39;log10(&#39; . \$n . &#39;) = &#39; . number_format(\$logVal, 2) . &#39;<br>&#39;;
}

" ; echo "

輸出效果：

" ; foreach ([ 10 , 100 , 1000 , 12345 ] as $n ) { $logVal = log10 ( $n ); echo "log10( $n ) = " . number_format ( $logVal , 2 ) . "
" ; } echo "

總結

" ; echo "

結合log10()與number_format()可以方便地計算數字的對數，並將結果以更易讀的格式輸出，特別適用於報表、統計分析或金融計算等場景。

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