archived-doc-zh/reference/strings/functions/sprintf.xml

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<!-- EN-Revision: 45042fef652f1b4e904e809fcbfcf31f6c60670b Maintainer: mowangjuanzi Status: ready -->
<refentry xml:id="function.sprintf" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>sprintf</refname>
  <refpurpose>返回格式化字符串</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>string</type><methodname>sprintf</methodname>
   <methodparam><type>string</type><parameter>format</parameter></methodparam>
   <methodparam rep="repeat"><type>mixed</type><parameter>values</parameter></methodparam>
  </methodsynopsis>
  <para>
   返回一个根据格式化字符串 <parameter>format</parameter> 生成的字符串。
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    &strings.parameter.format;
    <varlistentry>
     <term><parameter>values</parameter></term>
     <listitem>
      <para>
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   返回一个根据格式化字符串 <parameter>format</parameter> 生成的字符串。
  </para>
 </refsect1>

 <refsect1 role="errors">
  &reftitle.errors;
  &strings.errors.sprintf;
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  &strings.changelog.sprintf;
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <example>
   <title>参数替换</title>
   <para>
    支持按顺序用参数替换格式字符串里的占位符。
   </para>
   <programlisting role="php">
    <![CDATA[
<?php
$num = 5;
$location = 'tree';

$format = 'There are %d monkeys in the %s';
echo sprintf($format, $num, $location);
?>
]]>
   </programlisting>
   &example.outputs;
   <screen>
<![CDATA[
There are 5 monkeys in the tree
]]>
   </screen>
  </example>
  <para>
    假设，我们想把它国际化，在一个单独的文件中创建格式字符串，我们将它重写为：
  </para>
  <example>
   <title>错误的参数顺序</title>
   <para>
    格式字符串支持参数编号/交换。
   </para>
   <programlisting role="php">
    <![CDATA[
<?php
$num = 5;
$location = 'tree';

$format = 'The %s contains %d monkeys';
echo sprintf($format, $num, $location);
?>
]]>
   </programlisting>
  </example>
  <para>
   我们现在有一个问题。
   格式字符串中占位符的顺序与代码中参数的顺序不匹配。
   我们希望保持代码原样，并在格式字符串中简单地指出占位符引用的参数。
   我们可以这样写格式化字符串：
  </para>

  <example>
   <title>使用顺序占位符</title>
   <programlisting role="php">
    <![CDATA[
<?php
$num = 5;
$location = 'tree';

$format = 'The %2$s contains %1$d monkeys';
echo sprintf($format, $num, $location);
?>
]]>
   </programlisting>
  </example>

  <para>
   另外一个好处是占位符可以重复使用，而无需在代码中添加更多参数。
  </para>

  <example>
   <title>重复占位符</title>
   <programlisting role="php">
    <![CDATA[
<?php
$num = 5;
$location = 'tree';

$format = 'The %2$s contains %1$d monkeys.
           That\'s a nice %2$s full of %1$d monkeys.';
echo sprintf($format, $num, $location);
?>
]]>
   </programlisting>
  </example>

  <para>
   当使用参数替换时，<literal>n$</literal>
   <emphasis>位置指示符</emphasis> 必须紧跟在百分号（<literal>%</literal>）之后，在任何其他指示符之前，如下所示。
  </para>

  <example>
   <title>指定填充字符</title>
   <programlisting role="php">
<![CDATA[
<?php
echo sprintf("%'.9d\n", 123);
echo sprintf("%'.09d\n", 123);
?>
]]>
   </programlisting>
   &example.outputs;
   <screen>
<![CDATA[
......123
000000123
]]>
   </screen>
  </example>

  <example>
   <title>位置说明符与其他说明符</title>
   <programlisting role="php">
<![CDATA[
<?php
$num = 5;
$location = 'tree';

$format = 'The %2$s contains %1$04d monkeys';
echo sprintf($format, $num, $location);
?>
]]>
   </programlisting>
   &example.outputs;
   <screen>
<![CDATA[
The tree contains 0005 monkeys
]]>
   </screen>
  </example>

  <example>
   <title><function>sprintf</function>：零填充整数</title>
   <programlisting role="php">
<![CDATA[
<?php
$year = 2005;
$month = 5;
$day = 6;

$isodate = sprintf("%04d-%02d-%02d", $year, $month, $day);
echo $isodate, PHP_EOL;
?>
]]>
   </programlisting>
  </example>

  <example>
   <title><function>sprintf</function>：货币格式</title>
   <programlisting role="php">
<![CDATA[
<?php
$money1 = 68.75;
$money2 = 54.35;
$money = $money1 + $money2;
echo $money, PHP_EOL;

$formatted = sprintf("%01.2f", $money);
echo $formatted, PHP_EOL;
?>
]]>
   </programlisting>
   &example.outputs;
   <screen>
<![CDATA[
123.1
123.10
]]>
   </screen>
  </example>
  <example>
   <title><function>sprintf</function>：科学记数法</title>
   <programlisting role="php">
<![CDATA[
<?php
$number = 362525200;

echo sprintf("%.3e", $number), PHP_EOL;
?>
]]>
   </programlisting>
   &example.outputs;
   <screen>
<![CDATA[
3.625e+8
]]>
   </screen>
  </example>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>printf</function></member>
    <member><function>fprintf</function></member>
    <member><function>vprintf</function></member>
    <member><function>vsprintf</function></member>
    <member><function>vfprintf</function></member>
    <member><function>sscanf</function></member>
    <member><function>fscanf</function></member>
    <member><function>number_format</function></member>
    <member><function>date</function></member>
   </simplelist>
  </para>
 </refsect1>

</refentry>
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