The main difference between single quotes and double quotes in PHP is variable parsing and escape character processing. Single quotes do not parse variables or escape characters, while double quotes parse variables and allow escape characters. In addition, double quotes support Heredoc and Nowdoc syntax, while single quotes do not.
The difference between single quotes and double quotes in PHP
In PHP, single quotes (') and double quotes Quotes (") are both string delimiters used to surround strings. However, there are some key differences between them:
Variable parsing:
For example:
<code class="php">$name = 'John'; echo 'My name is $name.'; // 输出 My name is $name echo "My name is $name."; // 输出 My name is John</code>
Escape characters:
<code class="php">echo 'This is a single-quoted string with a backslash: \n'; // 输出 This is a single-quoted string with a backslash: \n echo "This is a double-quoted string with a backslash: \n"; // 输出 This is a double-quoted string with a backslash:</code>
##Single quotes: Not supported Double quotes: Heredoc and Nowdoc are supported. Nowdoc syntax.
<code class="php">// 使用双引号 $text = <<<EOT 这是使用双引号创建的多行字符串。 可以包含变量:$name EOT; // 使用单引号(不受支持) $text = <<<'EOT' 这是使用单引号创建的多行字符串。 无法包含变量:$name EOT;</code>
Other differences:
Single quotes have higher precedence than double quotes, which means that when nested strings are encountered, the outer single quotes will take precedence Double quotes. Unicode escape sequences (such as \u00A0) are supported, but single quotes are not supported
If the string contains variables or requires Heredoc/Nowdoc syntax, please use double quotes.
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