No matter which project I’m working on, I always need regular expressions; not on a daily basis though, but it always comes handy to know how to use them.
The thing is, I also always forget how to use them, so I decided to create this page to remember the ones that helped me out !
Add beginning and closing string delimiter (« ) and a comma to all the words in a list :
search with : ^([A-Z0-9]+)
replace with : "\1",
provided that \1 represents the matching sequence in your regexp software (\n is used in Notepad++, some others may use %n)
Web page that helped me found the information :
http://notepad-plus.sourceforge.net/uk/regExpList.php
Turning a copied pasted array into a an int array
Given this :
0 -1 -2 -3 +3 +2 +1
+1 0 -1 -2 -3 +3 +2
+2 +1 0 -1 -2 -3 +3
+3 +2 +1 0 -1 -2 -3
-3 +3 +2 +1 0 -1 -2
-2 -3 +3 +2 +1 0 -2
-1 -2 -3 +3 +2 +1 0
if you first replace the tabs with commas,
search with : \t
replace with : ,, you get this :
0,-1,-2,-3,+3,+2,+1
+1,0,-1,-2,-3,+3,+2
+2,+1,0,-1,-2,-3,+3
+3,+2,+1,0,-1,-2,-3
-3,+3,+2,+1,0,-1,-2
-2,-3,+3,+2,+1,0,-2
-1,-2,-3,+3,+2,+1,0
and then using :
search with : (\w)$
replace with : \1},{, you get this :
0,-1,-2,-3,+3,+2,+1},{
+1,0,-1,-2,-3,+3,+2},{
+2,+1,0,-1,-2,-3,+3},{
+3,+2,+1,0,-1,-2,-3},{
-3,+3,+2,+1,0,-1,-2},{
-2,-3,+3,+2,+1,0,-2},{
-1,-2,-3,+3,+2,+1,0},{
which is approximately an int[][]
Finding a string
For example, if you want to find the string:
class="XXXX"
meaning you’re looking for a string beginning with class= and ending with a blank; you can use this regexp :
class[^ ]*
which will find every occurences of « class », followed by every caracters possible but » » and then ending with » « .
I found this regexp reading this (french) discussion :
http://www.commentcamarche.net/forum/affich-1062011-php-supprimer-d-une-sous-chaine-a-une-autre
Search and replace a letter following a word using regexps
Imagine you want to search and replace the 4th letter of all words beginning with « set »
Then, search with set(.)
replace with before\1after
Example : setAbc() would become beforeAafterbc()
Decorate a string using regular expressions
As a java programmer, I want to replace word by private String word;
search with ^(.*)$
replace with private String \1;
Matching a regexp and saving results in a file, using Groovy
Problem : « I want to save all occurences of a regexp in a file »
Sadly, Notepad++ could not help me this time, so I decided to write my own sript to achieve that; I chose Groovy as I knew it provided a nice support for regexp manipulations; and also I thought it would be a nice occasion to try it out !
def file = "C:/tmp/my_file_containing_sql_instructions_and_other_stuff.txt" def stringToWrite= new StringBuilder() fileInAsString = new File(file).text theRegularExpression = /select ([A-Za-z0-9\_\.\ \,\=\:]*)/ matcher = ( fileInAsString =~ theRegularExpression ) matcher.each({ value -> stringToWrite < < value.get(0) && stringToWrite << "\n" }) def out = "C:/tmp/my_outputfile_containing_only_select_sql_instructions.txt" fileOut = new File(out) fileOut.write(stringToWrite.toString())
Groovy isn’t it ? (the value.get(0) is because the match is repeated twice in value)
