Find Lowercase immediately followed by uppercase

问题

My text is as below:

<font size=+2 color=#F07500><b> [ba]</font></b>
<ul><li><font color =#0B610B> Word word wordWord word.<br></font></li></ul>
<ul><li><font color =#F07500> Word word word.<br></font></li></ul>
<ul><li><font color =#0B610B> Word word word wordWord.<br></font></li></ul>
<ul><li><font color =#0B610B> WordWord.<br></font></li></ul>
<br><font color =#E41B17><b>UPPERCASE LETTERS</b></font> 
<ul><li><font color =#0B610B> Word word wordWord word.<br></font><br><font color =#E41B17><b>PhD and dataBase</b></font> </li></ul>
<font color =#0B610B> Word word word.<br></font></li></ul><dd><font color =#F07500>     »» Word wordWord word.<br></font>

There is a lowercase letter immediately followed by an uppercase in each of the .... For example:

<font color =#0B610B> Word word wordWord word.<br></font>

I want to correct this error by splitting them as follows (i.e: adding a colon and a space between them):

<font color =#0B610B> Word word word: Word word.<br></font>

So far, I have been using:

(<font color =#0B610B\b[^>]*>)(.*?</font>)

to select each of the instances of ..., and it works fine in finding one instance by one instance of ....

But when I use:

(<font color =#0B610B\b[^>]*>)(.*?[a-z])([A-Z].*?</font>)

it does find but selects everything between ...in one line regardless of other font-color tags, and replaces other unwanted instances.

I want it to find and replace error in each of this specific pair of tags: ..., not grabbing everything starting by  and ending in 

Are there any regular expressions to solve this problem? Many thanks in advance.

回答1:

In general, regex is not a good idea for parsing HTML (if it's a once-off you might be OK).

I think this might be the reason your regex is not working. Can you give an example of a case in which your regex fails?

One case I can think of if is there is no match ([a-z][A-Z]) within a matching  pair, but there is in a neighbouring . For example:

<font color=#0B610B>word word</font><font color=#000000>word wordWord</font>

In this case, the only valid match is word wordword word and the rest of the string Word, and so this is what the regex matches (since if it can match it will!)

I can think of a crude workaround but I wouldn't recommend it unless this task is a once-off because using regex for HTML is always prone to such errors!. This regex is also pretty inefficient. Try (untested):

(<font color =#0B610B\b[^>]*>)(([^<]|<(?!/font))*?[a-z])([A-Z].*?</font>)

It says, "look for the  tag, followed by either an angle bracket < not followed by /font, OR anything else, and again followed by the [a-z][A-Z]". So it tries to make sure that the match doesn't go over a  boundary.

来源：https://stackoverflow.com/questions/8775419/find-lowercase-immediately-followed-by-uppercase

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