使用正则表达式自动换行 [英] Word Wrapping with Regular Expressions
问题描述
编辑CLARITY - 我知道有办法在多个步骤来做到这一点，或使用LINQ或香草C＃字符串操作。我使用的是单一的正则表达式的电话，原因是因为我想练习复杂的正则表达式模式。 - 编辑完
EDIT FOR CLARITY - I know there are ways to do this in multiple steps, or using LINQ or vanilla C# string manipulation. The reason I am using a single regex call, is because I wanted practice with complex regex patterns. - END EDIT
我想写一个正则表达式将执行自动换行。这是非常接近所需的输出，但我不能完全得到它的工作。
I am trying to write a single regular expression that will perform word wrapping. It's extremely close to the desired output, but I can't quite get it to work.
Regex.Replace(text, @"(?<=^|\G)(.{1,20}(\s|$))", "$1\r\n", RegexOptions.Multiline)
这是正确的包装字太长线，但它添加一个换行符时已经是其中之一。
This is correctly wrapping words for lines that are too long, but it's adding a line break when there already is one.
输入
"This string is really long. There are a lot of words in it.\r\nHere's another line in the string that's also very long."
预计输出
Expected Output
"This string is \r\nreally long. There \r\nare a lot of words \r\nin it.\r\nHere's another line \r\nin the string that's \r\nalso very long."
实际输出
Actual Output
"This string is \r\nreally long. There \r\nare a lot of words \r\nin it.\r\n\r\nHere's another line \r\nin the string that's \r\nalso very long.\r\n"
$ b $字符串b
请注意句子，其中输入已经有了一个换行符和额外的\r\\\
被放在句末的双\r\\\
。
Note the double "\r\n" between sentences where the input already had a line break and the extra "\r\n" that was put at the end.
或许有有条件地应用不同的替换模式的方法吗？
I.E.如果比赛以\r\\\
结尾，使用替代模式$ 1，否则，使用替代模式$ 1\r\\\
。
Perhaps there's a way to conditionally apply different replacement patterns? I.E. If the match ends in "\r\n", use replace pattern "$1", otherwise, use replace pattern "$1\r\n".
下面是一个类似的问题一个链接，包装与我作为一个起点，没有空白的字符串。
正则表达式找到完整的文本，插入空间
Here's a link to a similar question for wrapping a string with no white space that I used as a starting point. Regular expression to find unbroken text and insert space
推荐答案
这是Perl的快速测试。
This was quick-tested in Perl.
修改 - 此正则表达式的代码模拟在MS-Windows上的 Notepad.exe的的
Edit - This regex code simulates the word wrap used (good or bad) in MS-Windows Notepad.exe
# MS-Windows "Notepad.exe Word Wrap" simulation
# ( N = 16 )
# ============================
# Find: @"(?:((?>.{1,16}(?:(?<=[^\S\r\n])[^\S\r\n]?|(?=\r?\n)|$|[^\S\r\n]))|.{1,16})(?:\r?\n)?|(?:\r?\n|$))"
# Replace: @"$1\r\n"
# Flags: Global
# Note - Through trial and error discovery, it apparears Notepad accepts an extra whitespace
# (possibly in the N+1 position) to help alignment. This matters not because thier viewport hides it.
# There is no trimming of any whitespace, so the wrapped buffer could be reconstituted by inserting/detecting a
# wrap point code which is different than a linebreak.
# This regex works on un-wrapped source, but could probably be adjusted to produce/work on wrapped buffer text.
# To reconstitute the source all that is needed is to remove the wrap code which is probably just an extra "\r".
(?:
# -- Words/Characters
( # (1 start)
(?> # Atomic Group - Match words with valid breaks
.{1,16} # 1-N characters
# Followed by one of 4 prioritized, non-linebreak whitespace
(?: # break types:
(?<= [^\S\r\n] ) # 1. - Behind a non-linebreak whitespace
[^\S\r\n]? # ( optionally accept an extra non-linebreak whitespace )
| (?= \r? \n ) # 2. - Ahead a linebreak
| $ # 3. - EOS
| [^\S\r\n] # 4. - Accept an extra non-linebreak whitespace
)
) # End atomic group
|
.{1,16} # No valid word breaks, just break on the N'th character
) # (1 end)
(?: \r? \n )? # Optional linebreak after Words/Characters
|
# -- Or, Linebreak
(?: \r? \n | $ ) # Stand alone linebreak or at EOS
)
测试用例的卷绕宽度N是16输出相匹配的记事本的，并在各种宽度。
Test Case The wrap width N is 16. Output matches Notepad's and over a variety of widths.
$/ = undef;
$string1 = <DATA>;
$string1 =~ s/(?:((?>.{1,16}(?:(?<=[^\S\r\n])[^\S\r\n]?|(?=\r?\n)|$|[^\S\r\n]))|.{1,16})(?:\r?\n)?|(?:\r?\n|$))/$1\r\n/g;
print $string1;
__DATA__
hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
bbbbbbbbbbbbbbbbEDIT FOR CLARITY - I know there are ways to do this in multiple steps, or using LINQ or vanilla C#
string manipulation.
The reason I am using a single regex call, is because I wanted practice. with complex
regex patterns. - END EDIT
pppppppppppppppppppUf
输出>>
hhhhhhhhhhhhhhhh
hhhhhhhhhhhhhhh
bbbbbbbbbbbbbbbb
EDIT FOR CLARITY
- I
know there
are ways to do
this in
multiple steps,
or using LINQ or
vanilla C#
string
manipulation.
The reason I am
using a single
regex call, is
because I wanted
practice. with
complex
regex patterns.
- END EDIT
pppppppppppppppp
pppUf
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