如何修剪string(6) " page"，其中第一个空格是 0xc2a0 不间断空格？
我试过trim() 和preg_match('/^\s*(.*)\s*$/u', $key, $m);。
另一个问题：如何可靠地复制这些字符？它们似乎被转换为“正常”空间，这使得调试变得困难。
【问题讨论】：
标签： php unicode utf-8 whitespace character-properties
preg_replace('/^[\pZ\pC]+|[\pZ\pC]+$/u','',$str);
【讨论】：
u 修饰符，并且 s 没有什么意义。工作代码：preg_replace('/^\p{Z}+|\p{Z}+$/u', '', $key).
preg_replace('/^[\pZ\pC]+|[\pZ\pC]+$/u'。
/x 或(?x) 在正则表达式上使用非疯狂模式？
PCRE unicode properties 属性可以用来实现这个
这是我玩过的代码，似乎可以满足您的要求：
<?php
function unicode_trim ($str) {
return preg_replace('/^[\pZ\pC]+([\PZ\PC]*)[\pZ\pC]+$/u', '$1', $str);
}
$key = chr(0xc2) . chr(0xa0) . '#page#' . chr(0xc2) . chr(0xa0);
var_dump(unicode_trim($key));
结果
[~]> php e.php
string(6) "#page#"
解释：
\p{xx} 具有 xx 属性的字符 \P{xx} 没有 xx 属性的字符
如果 xx 只有一个字符，则可以删除 {}，例如\p{Z} 与 \pZ
相同Z 代表所有分隔符，C 代表所有“其他”字符（例如控制字符）
【讨论】：
现有解决方案仅提及 \pZ 字符。但是，有六个 Unicode 空白字符不在该属性的范围内：
% unichars '\p{WhiteSpace}' '\PZ'
-- 9 0009 CHARACTER TABULATION
-- 10 000A LINE FEED (LF)
-- 11 000B LINE TABULATION
-- 12 000C FORM FEED (FF)
-- 13 000D CARRIAGE RETURN (CR)
-- 133 0085 NEXT LINE (NEL)
这六个都是\pC 类型，尤其是\p{Cc}。但是有 59 个非空白字符也是 \p{Cc}：
% unichars '\P{WhiteSpace}' '\p{Cc}' | wc -l
59
我自己测试某个东西是否是可打印字符的简单版本就是[\pZ\pC]；例如，unichars 就是这样使用的。
更仔细的测试会考虑是否应该占用 0、1 或 2 个打印位置。这需要考虑它是否是组合标记，即属性\pM，以及它是否具有半角或全角属性。例如：
% uniprops ff5e ffeb
U+FF5E ‹～› \N{ FULLWIDTH TILDE }:
\pS \p{Sm}
All Any Assigned InHalfwidthAndFullwidthForms Changes_When_NFKC_Casefolded
CWKCF Common Zyyy Sm S Gr_Base Grapheme_Base Graph GrBase Math
Math_Symbol Print Symbol
U+FFEB ‹￫› \N{ HALFWIDTH RIGHTWARDS ARROW }:
\pS \p{Sm}
All Any Assigned InHalfwidthAndFullwidthForms Changes_When_NFKC_Casefolded
CWKCF Common Zyyy Sm S Gr_Base Grapheme_Base Graph GrBase Math
Math_Symbol Print Symbol
对于这些，您需要使用非二进制东亚宽度属性。这些是适用的：
% uniprops -l | grep -i width
Block:Halfwidth_And_Fullwidth_Forms
InHalfwidthAndFullwidthForms
East_Asian_Width:A
East_Asian_Width=Ambiguous
East_Asian_Width:Ambiguous
East_Asian_Width:F
East_Asian_Width=Fullwidth
East_Asian_Width:Fullwidth
East_Asian_Width:H
East_Asian_Width=Halfwidth
East_Asian_Width:Halfwidth
East_Asian_Width=Neutral
East_Asian_Width:Na
East_Asian_Width=Narrow
East_Asian_Width:Narrow
East_Asian_Width:Neutral
East_Asian_Width:W
East_Asian_Width=Wide
East_Asian_Width:Wide
它们有\p{Ea=F} 和\p{Ea=H} 之类的缩写。有很多这样的：
% uninames '(FULL|HALF)WIDTH' | wc -l
454
当然，你不能为这些东西命名，而要为属性：
% unichars '[\p{Ea=F}\p{Ea=H}]' | wc -l
227
% unichars '[\p{Ea=F}\p{Ea=H}\p{Ea=Na}]' | wc -l
338
% unichars '[\p{Ea=F}\p{Ea=H}\p{Ea=Na}\pM]' | wc -l
1488
为了向您展示这些东西真正有多少、许多属性，这里是三个不同字符的完整属性转储，针对 Unicode 5.2 运行：
% uniprops -ga NEL "COMBINING TILDE" ff5e
U+0085 ‹U+0085› \N{ NEXT LINE (NEL) }:
\s \v \R \pC \p{Cc}
All Any Assigned InLatin1 C Other Cc Cntrl Common Zyyy Control Pat_WS Pattern_White_Space PatWS Space SpacePerl VertSpace
White_Space WSpace
Age:1.1 Bidi_Class:B Bidi_Class=Paragraph_Separator Bidi_Class:Paragraph_Separator Bc=B Block:Latin_1
Block=Latin_1_Supplement Block:Latin_1_Supplement Blk=Latin1 General_Category=Other Canonical_Combining_Class:0
Canonical_Combining_Class=Not_Reordered Canonical_Combining_Class:Not_Reordered Ccc=NR Canonical_Combining_Class:NR
General_Category=Control Script=Common Decomposition_Type:None Dt=None East_Asian_Width=Neutral East_Asian_Width:Neutral
General_Category:C General_Category:Cc General_Category:Cntrl General_Category:Control Gc=Cc General_Category:Other Gc=C
Grapheme_Cluster_Break:CN Grapheme_Cluster_Break=Control Grapheme_Cluster_Break:Control GCB=CN Hangul_Syllable_Type:NA
Hangul_Syllable_Type=Not_Applicable Hangul_Syllable_Type:Not_Applicable Hst=NA Joining_Group:No_Joining_Group
Jg=NoJoiningGroup Joining_Type:Non_Joining Jt=U Joining_Type:U Joining_Type=Non_Joining Line_Break:Next_Line Lb=NL
Line_Break:NL Line_Break=Next_Line Numeric_Type:None Nt=None Numeric_Value:NaN Nv=NaN Present_In:1.1 Age=1.1 In=1.1
Present_In:2.0 In=2.0 Present_In:2.1 In=2.1 Present_In:3.0 In=3.0 Present_In:3.1 In=3.1 Present_In:3.2 In=3.2
Present_In:4.0 In=4.0 Present_In:4.1 In=4.1 Present_In:5.0 In=5.0 Present_In:5.1 In=5.1 Present_In:5.2 In=5.2
Script:Common Sc=Zyyy Script:Zyyy Sentence_Break:SE Sentence_Break=Sep Sentence_Break:Sep SB=SE Word_Break:Newline WB=NL
Word_Break:NL Word_Break=Newline
U+0303 ‹̃› \N{ COMBINING TILDE }:
\w \pM \p{Mn}
All Any Assigned InCombiningDiacriticalMarks Case_Ignorable CI Dia Diacritic M Mn Gr_Ext Grapheme_Extend Graph GrExt
ID_Continue IDC Inherited Zinh Mark Nonspacing_Mark Print Qaai Word XID_Continue XIDC
Age:1.1 Bidi_Class:Nonspacing_Mark Bc=NSM Bidi_Class:NSM Bidi_Class=Nonspacing_Mark Block:Combining_Diacritical_Marks
Canonical_Combining_Class:230 Canonical_Combining_Class=Above Canonical_Combining_Class:A
Canonical_Combining_Class:Above Ccc=A Decomposition_Type:None Dt=None East_Asian_Width:A East_Asian_Width=Ambiguous
East_Asian_Width:Ambiguous Ea=A General_Category:M General_Category=Mark General_Category:Mark Gc=M General_Category:Mn
General_Category=Nonspacing_Mark General_Category:Nonspacing_Mark Gc=Mn Grapheme_Cluster_Break:EX
Grapheme_Cluster_Break=Extend Grapheme_Cluster_Break:Extend GCB=EX Hangul_Syllable_Type:NA
Hangul_Syllable_Type=Not_Applicable Hangul_Syllable_Type:Not_Applicable Hst=NA Script=Inherited
Joining_Group:No_Joining_Group Jg=NoJoiningGroup Joining_Type:T Joining_Type=Transparent Joining_Type:Transparent Jt=T
Line_Break:CM Line_Break=Combining_Mark Line_Break:Combining_Mark Lb=CM NFC_Quick_Check:M NFC_Quick_Check=Maybe
NFC_Quick_Check:Maybe NFCQC=M NFKC_Quick_Check:M NFKC_Quick_Check=Maybe NFKC_Quick_Check:Maybe NFKCQC=M
Numeric_Type:None Nt=None Numeric_Value:NaN Nv=NaN Present_In:1.1 Age=1.1 In=1.1 Present_In:2.0 In=2.0 Present_In:2.1
In=2.1 Present_In:3.0 In=3.0 Present_In:3.1 In=3.1 Present_In:3.2 In=3.2 Present_In:4.0 In=4.0 Present_In:4.1 In=4.1
Present_In:5.0 In=5.0 Present_In:5.1 In=5.1 Present_In:5.2 In=5.2 Script:Inherited Sc=Zinh Script:Qaai Script:Zinh
Sentence_Break:EX Sentence_Break=Extend Sentence_Break:Extend SB=EX Word_Break:Extend WB=Extend
U+FF5E ‹～› \N{ FULLWIDTH TILDE }:
\pS \p{Sm}
All Any Assigned InHalfwidthAndFullwidthForms Changes_When_NFKC_Casefolded CWKCF Common Zyyy Sm S Gr_Base Grapheme_Base
Graph GrBase Math Math_Symbol Print Symbol
Age:1.1 Bidi_Class:ON Bidi_Class=Other_Neutral Bidi_Class:Other_Neutral Bc=ON Block:Halfwidth_And_Fullwidth_Forms
Canonical_Combining_Class:0 Canonical_Combining_Class=Not_Reordered Canonical_Combining_Class:Not_Reordered Ccc=NR
Canonical_Combining_Class:NR Script=Common Decomposition_Type:Non_Canon Decomposition_Type=Non_Canonical
Decomposition_Type:Non_Canonical Dt=NonCanon Decomposition_Type:Wide Dt=Wide East_Asian_Width:F
East_Asian_Width=Fullwidth East_Asian_Width:Fullwidth Ea=F General_Category:Math_Symbol Gc=Sm General_Category:S
General_Category=Symbol General_Category:Sm General_Category=Math_Symbol General_Category:Symbol Gc=S
Grapheme_Cluster_Break:Other GCB=XX Grapheme_Cluster_Break:XX Grapheme_Cluster_Break=Other Hangul_Syllable_Type:NA
Hangul_Syllable_Type=Not_Applicable Hangul_Syllable_Type:Not_Applicable Hst=NA Joining_Group:No_Joining_Group
Jg=NoJoiningGroup Joining_Type:Non_Joining Jt=U Joining_Type:U Joining_Type=Non_Joining Line_Break:ID
Line_Break=Ideographic Line_Break:Ideographic Lb=ID Numeric_Type:None Nt=None Numeric_Value:NaN Nv=NaN Present_In:1.1
Age=1.1 In=1.1 Present_In:2.0 In=2.0 Present_In:2.1 In=2.1 Present_In:3.0 In=3.0 Present_In:3.1 In=3.1 Present_In:3.2
In=3.2 Present_In:4.0 In=4.0 Present_In:4.1 In=4.1 Present_In:5.0 In=5.0 Present_In:5.1 In=5.1 Present_In:5.2 In=5.2
Script:Common Sc=Zyyy Script:Zyyy Sentence_Break:Other SB=XX Sentence_Break:XX Sentence_Break=Other Word_Break:Other
WB=XX Word_Break:XX Word_Break=Other
很漂亮，嗯？
如果您已经阅读了本文，并且想知道从哪里可以获得上述三个 Unicode 实用程序 uniprops、unichars 和 uninames，请给我发邮件，因为当前链接不可用现在工作。
【讨论】：
也许来自多字节字符串函数集？ http://php.net/manual/en/function.mb-ereg.php 看不到 mb_trim，但是有一组 MB 安全的正则表达式函数。
G
【讨论】：
【讨论】：
但是这里是我唯一的解决方案，因为有时会有 UTF8 空格：
$stringg = preg_replace('/^[\pZ\pC]+|[\pZ\pC]+$/u','',$stringg);
$stringg = preg_replace('/\s+/u', '', $stringg);
【讨论】：
【讨论】：