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iterating through a string, choosing a pattern
Pattern matching example from a Well House Consultants training course
More on Pattern matching [link]

This example is described in the following article(s):
   • Lua Regular Expressions - [link]

Source code: patplode Module: U108

Here are some examples of how you can iterate through a
string collecting the sections that match a particular pattern

print ("\niterating through the words in a string")
stuff = "to iterate through this, we match at ... punctuation!"
for k in string.gmatch(stuff,'%w+') do
        print (k)

print ("\nAlternative - capturing non-spaces")
for k in string.gmatch(stuff,'%S+') do
        print (k)

print ("\nCapture a char, then greedy to last repeat of it")
for k,j,l in string.gmatch(stuff,'(.)(.*)(%1)') do
        print (k,j,l)

print ("\nCapture a char, then sparse to last repeat of it")
for k,j,l in string.gmatch(stuff,'(.)(.-)(%1)') do
        print (k,j,l)

print ("\n6 chars at a time, 2 to one variable and 4 to another")
for k,j in string.gmatch(stuff,'(..)(....)') do
        print (k,j)

print ("\niterating through the parameters to a CGI script")
cgistring = 'this=17&that=24&somemore=extra text'
for k3,k4 in string.gmatch(cgistring,'([^=&]+)=([^&]+)') do
        print (k3,k4)

--[[ ------------------ Sample output -------------------
[trainee@easterton u108]$ lua patplode

iterating through the words in a string

Alternative - capturing non-spaces

Capture a char, then greedy to last repeat of it
t o iterate through this, we match at ... punctua t

Capture a char, then sparse to last repeat of it
t o i t
e rat e
t his, we ma t
c h at ... pun c
t ua t

6 chars at a time, 2 to one variable and 4 to another
 i tera
te thr
ou gh t
hi s, w
e matc
h at .
.. pun
ct uati

iterating through the parameters to a CGI script
this 17
that 24
somemore extra text
[trainee@easterton u108]$


Learn about this subject
This module and example are covered on the following public courses:
 * Learning to program in Lua
 * Lua Programming
 * Lua Programming
Also available on on site courses for larger groups

Books covering this topic
Yes. We have over 700 books in our library. Books covering Lua are listed here and when you've selected a relevant book we'll link you on to Amazon to order.

Other Examples
This example comes from our "Pattern matching" training module. You'll find a description of the topic and some other closely related examples on the "Pattern matching" module index page.

Full description of the source code
You can learn more about this example on the training courses listed on this page, on which you'll be given a full set of training notes.

Many other training modules are available for download (for limited use) from our download centre under an Open Training Notes License.

Other resources
• Our Solutions centre provides a number of longer technical articles.
• Our Opentalk forum archive provides a question and answer centre.
The Horse's mouth provides a daily tip or thought.
• Further resources are available via the resources centre.
• All of these resources can be searched through through our search engine
• And there's a global index here.

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This is a sample program, class demonstration or answer from a training course. It's main purpose is to provide an after-course service to customers who have attended our public private or on site courses, but the examples are made generally available under conditions described below.

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This web site is written and maintained by Well House Consultants.

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