我认为这个话题讨论得太多了/太复杂了。使用IDE是完全避免任何语法错误的方法。我甚至会说，在没有IDE的情况下工作是不专业的。为什么?因为现代ide会在输入每个字符后检查语法。当您编写代码时，整行代码都变成红色，并且有一个很大的警告通知显示语法错误的确切类型和确切位置，那么绝对没有必要搜索其他解决方案。

使用语法检查IDE意味着:

您将(有效地)再也不会遇到语法错误，因为您在输入时就能看到它们。认真对待。

具有语法检查功能的优秀ide(它们都适用于Linux、Windows和Mac):

NetBeans(免费) PHPStorm [$199 USD] Eclipse与PHP插件[免费] Sublime [$80 USD](主要是一个文本编辑器，但可扩展的插件，如PHP语法分析器)

对于VS Code的新手，如果你看到语法错误，检查你是否保存了文件。如果你有一个错误的语法，保存文件，然后在不保存的情况下修复语法，VS Code会继续显示错误。只有保存文件后，错误信息才会消失。

意外的T_CONSTANT_ENCAPSED_STRING意外的t_encapsed_and_空白

T_CONSTANT_ENCAPSED_STRING和T_ENCAPSED_AND_WHITESPACE是指带引号的“字符串”字面量。

它们在不同的上下文中使用，但语法问题非常相似。t_encaged…警告出现在双引号的字符串上下文中，而T_CONSTANT…字符串经常在普通PHP表达式或语句中出错。

Incorrect variable interpolation And it comes up most frequently for incorrect PHP variable interpolation: ⇓ ⇓ echo "Here comes a $wrong['array'] access"; Quoting arrays keys is a must in PHP context. But in double quoted strings (or HEREDOCs) this is a mistake. The parser complains about the contained single quoted 'string', because it usually expects a literal identifier / key there. More precisely it's valid to use PHP2-style simple syntax within double quotes for array references: echo "This is only $valid[here] ..."; Nested arrays or deeper object references however require the complex curly string expression syntax: echo "Use {$array['as_usual']} with curly syntax."; If unsure, this is commonly safer to use. It's often even considered more readable. And better IDEs actually use distinct syntax colorization for that. Missing concatenation If a string follows an expression, but lacks a concatenation or other operator, then you'll see PHP complain about the string literal: ⇓ print "Hello " . WORLD " !"; While it's obvious to you and me, PHP just can't guess that the string was meant to be appended there. Confusing string quote enclosures The same syntax error occurs when confounding string delimiters. A string started by a single ' or double " quote also ends with the same. ⇓ print "<a href="' . $link . '">click here</a>"; ⌞⎽⎽⎽⎽⎽⎽⎽⎽⌟⌞⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⌟⌞⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⌟ That example started with double quotes. But double quotes were also destined for the HTML attributes. The intended concatenation operator within however became interpreted as part of a second string in single quotes. Tip: Set your editor/IDE to use slightly distinct colorization for single and double quoted strings. (It also helps with application logic to prefer e.g. double quoted strings for textual output, and single quoted strings only for constant-like values.) This is a good example where you shouldn't break out of double quotes in the first place. Instead just use proper \" escapes for the HTML attributes´ quotes: print "<a href=\"{$link}\">click here</a>"; While this can also lead to syntax confusion, all better IDEs/editors again help by colorizing the escaped quotes differently. Missing opening quote Equivalently are forgotten opening "/' quotes a recipe for parser errors: ⇓ make_url(login', 'open'); Here the ', ' would become a string literal after a bareword, when obviously login was meant to be a string parameter. Array lists If you miss a , comma in an array creation block, the parser will see two consecutive strings: array( ⇓ "key" => "value" "next" => "....", ); Note that the last line may always contain an extra comma, but overlooking one in between is unforgivable. Which is hard to discover without syntax highlighting. Function parameter lists The same thing for function calls: ⇓ myfunc(123, "text", "and" "more") Runaway strings A common variation are quite simply forgotten string terminators: ⇓ mysql_evil("SELECT * FROM stuffs); print "'ok'"; ⇑ Here PHP complains about two string literals directly following each other. But the real cause is the unclosed previous string of course. HEREDOC indentation Prior PHP 7.3, the heredoc string end delimiter can't be prefixed with spaces: print <<< HTML <link..> HTML; ⇑ Solution: upgrade PHP or find a better hoster.

另请参阅

PHP中关联数组的插值(双引号字符串) 语法错误，意外的T_CONSTANT_ENCAPSED_STRING 语法错误，PHP中意外的T_CONSTANT_ENCAPSED_STRING SQL查询中出现意外的T_CONSTANT_ENCAPSED_STRING错误

意想不到的T_LNUMBER

令牌T_LNUMBER指向一个“长”/ number。

Invalid variable names In PHP, and most other programming languages, variables cannot start with a number. The first character must be alphabetic or an underscore. $1 // Bad $_1 // Good Quite often comes up for using preg_replace-placeholders "$1" in PHP context: # ↓ ⇓ ↓ preg_replace("/#(\w+)/e", strtopupper($1) ) Where the callback should have been quoted. (Now the /e regex flag has been deprecated. But it's sometimes still misused in preg_replace_callback functions.) The same identifier constraint applies to object properties, btw. ↓ $json->0->value While the tokenizer/parser does not allow a literal $1 as variable name, one could use ${1} or ${"1"}. Which is a syntactic workaround for non-standard identifiers. (It's best to think of it as a local scope lookup. But generally: prefer plain arrays for such cases!) Amusingly, but very much not recommended, PHPs parser allows Unicode-identifiers; such that $➊ would be valid. (Unlike a literal 1). Stray array entry An unexpected long can also occur for array declarations - when missing , commas: # ↓ ↓ $xy = array(1 2 3); Or likewise function calls and declarations, and other constructs: func(1, 2 3); function xy($z 2); for ($i=2 3<$z) So usually there's one of ; or , missing for separating lists or expressions. Misquoted HTML And again, misquoted strings are a frequent source of stray numbers: # ↓ ↓ echo "<td colspan="3">something bad</td>"; Such cases should be treated more or less like Unexpected T_STRING errors. Other identifiers Neither functions, classes, nor namespaces can be named beginning with a number either: ↓ function 123shop() { Pretty much the same as for variable names.

意想不到的美元结束

当PHP谈到“意外的$end”时，这意味着您的代码在解析器期望更多代码时结束了。(如果从字面上理解，这个信息有点误导。它不是关于一个名为“$end”的变量，就像新来者有时认为的那样。它指的是“文件的结束”，EOF。)

原因:代码块/和函数或类声明的{和}不平衡。

它几乎总是缺少一个}花括号来关闭前面的代码块。它的意思是，解析器希望找到一个结束}，但实际上到达了文件的末尾。

同样，使用适当的缩进来避免此类问题。 使用带有括号匹配的IDE，找出}错误的地方。 在大多数ide和文本编辑器中都有快捷键: NetBeans, PhpStorm, Komodo: Ctrl[和Ctrl] Eclipse, Aptana: CtrlShiftP Atom, Sublime: Ctrlm - Zend Studio Ctrlm Geany, notepad++: CtrlB - Joe: CtrlG - Emacs: C-M-n - Vim: %

大多数ide还突出显示匹配的大括号、方括号和圆括号。 这使得检查它们的相关性变得非常容易:

无端接的表达式

对于未结束的表达式或语句，也会出现意外的$end语法/解析器错误:

$var = func（1， ？>EOF

因此，首先查看脚本的末尾。拖尾;在任何PHP脚本中，最后一条语句通常是多余的。但你应该有一个。正是因为它缩小了这些语法问题的范围。特别是在您发现自己在脚本末尾添加了更多语句之后。

缩进的HEREDOC标记

另一种常见情况出现在HEREDOC或NOWDOC字符串中。如果前面有空格、制表符等，终止标记将被忽略:

print <<< END
    Content...
    Content....
  END;
# ↑ terminator isn't exactly at the line start

因此，解析器假定HEREDOC字符串将一直持续到文件的末尾(因此是“意外的$end”)。几乎所有的ide和语法高亮编辑器都会明确显示或发出警告。

转义的引号

如果你在字符串中使用\，它有一个特殊的含义。这称为“转义字符”，通常告诉解析器按字面意思取下一个字符。

示例:echo 'Jim said \'Hello\ ";将打印Jim说'hello'

如果转义字符串的结束引号，结束引号将被字面上理解，而不是像预期的那样，即作为字符串的一部分而不是结束字符串的可打印引号。这通常会在打开下一个字符串后或脚本结束时显示为解析错误。

在Windows中指定路径时非常常见的错误:“C:\xampp\htdocs\”是错误的。你需要“C:\\xampp\\htdocs\\ \”。另外，PHP通常会转换unix风格的路径(例如。“C:/xampp/htdocs/”)到Windows的正确路径。

替代语法

在模板中使用语句/代码块的替代语法时，很少会看到这种语法错误。使用if:和else:和一个缺失的endif;为例。

参见:

PHP语法错误“意外$end” 解析错误:语法错误，在我的PHP代码文件意外结束 解析错误语法错误文件意外结束，使用PHP PHP解析错误:语法错误，CodeIgniter视图中的文件意外结束 解析错误:语法错误，文件意外结束(注册脚本) “解析错误:语法错误，意外$end”为我的uni注册分配 修复PHP错误:PHP错误#3:文件意外结束

意想不到的(

现在，在过时的PHP版本中经常可以看到意外的[array括号]。短数组语法从PHP >= 5.4开始可用。旧的安装只支持array()。

$php53 = array(1, 2, 3);
$php54 = [1, 2, 3];
         ⇑

数组函数结果解引用同样不适用于旧的PHP版本:

$result = get_whatever()["key"];
                      ⇑

这个错误在PHP中意味着什么?-“语法错误，意外的\[”显示了最常见和实用的解决方案。

不过，最好还是升级PHP安装。对于共享网络托管计划，首先要研究是否可以使用SetHandler php5 56-fcgi来启用新的运行时。

参见:

对函数result→进行解引用的PHP语法，从PHP 5.4开始可能 PHP语法错误，意外的“[” 数组的简写:是否存在像{}或[]这样的文字语法? PHP 5.3.10 vs PHP 5.5.3语法错误 数组()和[]的区别 PHP数组语法解析错误

顺便说一下，如果你对老版本和慢版本的PHP很感兴趣的话，还有预处理器和PHP 5.4语法下转换器。

导致意外语法错误的其他原因

如果不是PHP版本不匹配，那么通常是一个简单的拼写错误或新手语法错误:

You can't use array property declarations/expressions in classes, not even in PHP 7. protected $var["x"] = "Nope"; ⇑ Confusing [ with opening curly braces { or parentheses ( is a common oversight. foreach [$a as $b) ⇑ Or even: function foobar[$a, $b, $c] { ⇑ Or trying to dereference constants (before PHP 5.6) as arrays: $var = const[123]; ⇑ At least PHP interprets that const as a constant name. If you meant to access an array variable (which is the typical cause here), then add the leading $ sigil - so it becomes a $varname. You are trying to use the global keyword on a member of an associative array. This is not valid syntax: global $var['key'];

结束方括号

这种情况比较少见，但是终止数组[括号]也会出现语法错误。

同样，与)括号或}大括号不匹配是常见的: 函数foobar($a， $b， $c] { ⇑ 或者试图结束一个没有数组的数组: $var = 2]; 这通常发生在多行和嵌套数组声明中。 $数组=[1,2,3],4(5、6 (7 [8][9 10]],11),12]],15); ⇑ 如果是，请使用IDE进行括号匹配以查找任何过早的]数组闭包。至少使用更多的空格和换行来缩小范围。