Textpad and Finding ThingsA primer for the uninitiated

Graham LallyApril 2012

graham.lally@ocsi.co.ukhttp://www.ocsi.co.uk/

Coming up

• Hello Textpad• Learning to love Regular Expressions• Other useful things

Why Textpad?

                         Text-editing          Lots of options

http://www.textpad.com/

http://www.flickr.com/photos/eldholm/2354982554/ http://www.flickr.com/photos/grandmaitre/2387376806/ 

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Here are the files you have open

Write things here

Configure > Preferences

Basic set-up

Allow multiple instances to runReplace NotepadPut shortcut to Textpad on: Context Menu

Also set under "Editor" settings:

Use POSIX regular expression syntax

This means we can use ( ) and { } instead of \( \) and \{ \}

Shortcuts to get started

         Search current file(s)                         F5

         Search and replace                           F8 

         Search through a whole directory      Ctrl + F5

Regular Expressions

Why (oh why)?

    Regular expressions (REs / RegExps) let you search for a      *range* of things in one go, rather than just a single thing.

    

    

Old: Find "Kings Cross"

Kings XKing's X Kings CrossKing's Cross

RE: Find "King'?s (Cross|X)"

Kings XKing's X Kings CrossKing's Cross

Why Regular Expressions?

Also find:

        Any letter/number

        Any letter followed by any number

        Any number at the start/end of a line

        Any non-numbers

        etc.

My first regular expression

Regular expression

                                Find: .a

F5:

".a"

"." is a special character in REs, meaning find any character    (including letters, numbers, spaces and punctuation)

So "..." finds any 3 characters in a row: abc, 123, y r, even ...

                    .a              Find any character followed                                         by an "a", e.g. ba, 1a, %a

And "a.c" will find abc, aac, a6c, a?c, a c, a[c, a-c, etc

Characters to watch out for

In Textpad*, most characters do what they should.

Some don't:

               .    ?    *    +    |    [    ]    (    )    {    }    ^    $

To actually look for one of these, put a "\" before it. e.g. \? \( 

To look for a \, use \\

(* Other RegExp software may differ)

Finding other things

        [...]                Find any single character listed in the [ ]

                                e.g. [abc][123] will match a1, c1, b2, c3, etc

        ...|...              Find anything that matches before                                 or after the |

                            e.g. abc|123 will match abc and 123

                                Can also be more than 2: abc|123|xyz|000 

Counting things

Use +, * or ? after a character to indicate how many times it should occur:

            +               Find one or more characters                                  e.g. ab+c will find abc, abbc, abbbbbc, etc

            *                Find zero or more characters                                  e.g. ab*c will find ac, abc, abbc, abbbbbc, etc

            ?               Find zero or one characters (i.e. "maybe")                              e.g. ab?c will find ac and abc, but not abbc

Counting things

Use {min,max} after a character to set your own limits

    e.g. ab{4,6}c will find abbbbc, abbbbbc and abbbbbbc

max is optional too

    e.g. ab{3,}c will find abbbc, abbbbbbbbbbbbbbbbbbc, etc

min isn't optional in Textpad, so use 0 instead

    e.g. ab{0,3}c will find ac, abc, abbc, abbc

More character rangesTextpad also has some "named" ranges you can use, e.g.

        [:alpha:]            Any letter

        [:digit:]              Any digit

        [:blank:]            Space or tab

        [:space:]           Space, tab, return, line feed, et al

These go inside other [ ] e.g. [[:alpha:][:digit:]] finds any letter or number.

See TextPad's Help (available from the Find dialogue) for more.

Character ranges

Writing [0123456789] every time is silly.

Instead, use [...-...] (dash) to specify a range of characters.

    e.g. [0-9] to find any single number           [a-z] to find any letter 

These can be combined with themselves, plus other characters

    e.g. [a-z0-9:\.] to find any letter, number, colon or period

Line and word endings

        \n                Lets you look for line breaks,                             e.g. Hello\nworld will find Hello                                                                     world

         \< and \>   Match the start and end of a word

        ^                 Match the start of a line                            e.g. ^: will find any colon at the start of a line

        $                 Match the end of a line                            e.g. \.$ will find any period at the end of a line

Combine these to match whole lines, e.g. ^\?.*$ to match all lines that start with a question mark

Getting more complicated

Use (...) to set up "groups" - these can then be checked and counted in themselves

e.g. (hello)+ will find hello, hellohello, hellohellohello, etc.

       (hello|bye){2} will find hellohello, byebye, hellobye and byehello

       Hello (Tom|Stefan|Emma) will look for any of the 3 names

       (t[io]ck){2}! will find ticktock!, tocktick!, ticktick!, and tocktock!

More examples to figure out

What do the following regular expressions do?

        ^[0-9]{3}

        ^(Source|[0-9]{3})

        ^.*[0-9]{3}$

Replacements

F8

As expected, Textpad will replace anything matched, with the text specified.

Replacements

Remember though: 

The RE will (only/completely) match what you've typed. Textpad will replace what's been matched.

Work out what's being matched and what's being replaced.

e.g. We may want to match (find) all lines ending with a ?, but only replace the word before the ?

Replacements

A more useful example:

        [a-z]+[?!]$    Find any lines ending in letters, then ? or !

We want to replace the letters (i.e. [a-z]+) with something, but keep the ? or ! in place

But we don't know which one to use when replacing...

Replacements

Luckily, we can refer to things that have been matched using (...) groups.

Each group has its own number (in sequential order), and can be inserted using \n

e.g. [a-z]+([?!])$ has one (...) group: \1

        To replace the letters, we can use new word\1

        So hello! would become new word!

Replacements

Textpad uses \1 to \9 - which we can use wherever we want

e.g. ([a-z]+) ([0-9]+) will match Pelham 123

        Replacing this with \2 \1 gives us 123 Pelham

        Replacing it with \2\2 gives us 123123

(Be a bit careful if a (...) group is optional though, i.e. (...)? - if it's not found, your higher numbers will be wrong.)

Phew...

Can get tricky quickly, but remember:

o Use the "Help" button

o Use the "Find Next" button to check what your RE findso Check the Cheat Sheet - http://bit.ly/textpadref

Handy Tip 1: Multiple files

To replace across many files, open all the files and tick "All documents" when replacing:

Handy Tip 2: Searching a folder

To look through (closed) files in a directory, use Ctrl + F5. Tick "Search subfolders" if folders are several layers deep.

Handy Tip 3: Save everything

Finally:

You can see which files have changed - these have a * next to their filename.

You can also save all changes to all open files using:

File > Save All

Other Textpad Useful Bits

Block select mode (Ctrl+Q, then B):

                                                                   Bookmarked lines:

Cut/copy/deleteeverything selectedor bookmarked.

                                                    Bookmarks

http://xkcd.com/208/