regexp help - removing duplication

[Anon]

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question 1

i need to remove strings of characters from my strings and replace them with one character. for instance, if my string is

"this AAAAA is a test 222222". 

i want this to become

"this A is a test 2". 

how can i do this?

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question 2

can i make the same for strings? for example,

"this this this is a test"

i want it to become

"this is a test"

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question 3

can i make this generic, without specifying what string i want to remove duplication for? for example, in the question 2 above, i might have to specify that the string i want to remove duplication for is "this" (so that "this this this" becomes "this"). but can i make a function which will take a string, and remove any duplicate substrings?

thanks/erick

[[deleted]]

On a practical note:

What if you have a string that actually should contain a word twice?
Like here:

"He explained to me that that would be impossible"

here you don't want the second "that" to be erased.

[Anon]

hi vincent

thanks for your response, but once i have the function, of course i will use it wisely. :-) i only need to make it work for soem very specific cases.

can u help me with how to do it?

thanks/erick

[[deleted]]

Try this: (explenation available if required)

$a="this this this is 22222 a a string string string string with string aaaaaaa some bbbbbaaaaaad strings in it";

$without_aaaa=preg_replace("/(.{1})(\1)+(\W)/","\1\3",$a);

$without_double_words=preg_replace("/(\w+\W)(\1)+/","\1",$a);

echo $a."\n";

echo $without_aaaa."\n";

echo $without_double_words."\n";