Extract multiple occurrences of a substring using Powershell

Question

Given the following string:

'<p><a href="china">China</a><br><a href="india">India</a><br><a
href="korea">Korea</a><br><a href="malaysia">Malaysia</a><br><a
href="thailand">Thailand</a></p>'

I'd like to use Powershell to extract all of the countries listed therein. In other words I want to return @(China,India,Korea,Malaysia,Thailand).

Have tried using regex but can't find the right pattern, for example:

'<p><a href="china">China</a><br><a href="india">India</a><br><a href="korea">Korea</a><br><a href="malaysia">Malaysia</a><br><a href="thailand">Thailand</a></p>'  -match '(<a href="[A-Z a-z]*">[A-Z a-z]*</a>)+'
$matches

Which returns:

Name                           Value                                                                                                                                                                                            
----                           -----                                                                                                                                                                                            
1                              <a href="china">China</a>                                                                                                                                                                        
0                              <a href="china">China</a>

Any suggestions? Is regex the right approach here?

P.S. Note that the snippet is not well-formed so I can't simply convert it to XML.

Community · Accepted Answer · 2017-05-23 12:31:02Z

3

$Matches automatic variable contains information about matched capturing groups of last -match operation, not information about matches. If you want to get multiple matches of pattern, then you have to use Matches method from [Regex] class:

$InputString='<p><a href="china">China</a><br><a href="india">India</a><br><a href="korea">Korea</a><br><a href="malaysia">Malaysia</a><br><a href="thailand">Thailand</a></p>'
$Pattern='<a href="[A-Z a-z]*">([A-Z a-z]*)</a>'
$Countries=[Regex]::Matches($InputString,$Pattern)|ForEach-Object {$_.Groups[1].Value}
$Countries

Although for parsing HTML you better to use some HTML parser as other answer propose to you.

edited May 23, 2017 at 12:31

CommunityBot

11 silver badge

answered Jan 14, 2015 at 8:39

user4003407

22.3k4 gold badges54 silver badges62 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Duncan · Accepted Answer · 2015-01-15 09:01:24Z

1

Regular expressions are never a good way to handle HTML (though often they are tempting). You can parse the HTML and extract the data you want without using any regex:

PS C:\> $d = '<p><a href="china">China</a><br><a href="india">India</a><br><a
href="korea">Korea</a><br><a href="malaysia">Malaysia</a><br><a
href="thailand">Thailand</a></p>'


PS C:\> $html = New-Object -ComObject "HTMLFile"

PS C:\> $html.IHTMLDocument2_write($d)

PS C:\> $html.getElementsByTagName('A') | select -expandProperty innerText
China
India
Korea
Malaysia
Thailand

edited Jan 15, 2015 at 9:01

answered Jan 14, 2015 at 12:10

Duncan

96.4k15 gold badges129 silver badges160 bronze badges

2 Comments

jamiet Over a year ago

Nice. Didn't know about expandProperty. Thanks Duncan.

Duncan Over a year ago

Mostly with Powershell 3 and later you don't need to use expandProperty as you can usually just use dot notation. I don't know why it doesn't work here: ($html.getElementsByTagName('A')).innerText gives nothing while $html.getElementsByTagName('A') | select -expandProperty innerText works fine. I guess it must be because $html is a COM object.

Matija Lah · Accepted Answer · 2015-01-14 08:28:47Z

0

The following Regex should do the trick:

(?<=><a\shref="\w+">)\w+

ML

edited Jan 14, 2015 at 8:28

answered Jan 14, 2015 at 8:15

Matija Lah

212 bronze badges

Comments

qdl · Accepted Answer · 2018-05-09 13:52:22Z

0

$InputString='<p><a href="china">China</a><br><a href="india">India</a><br><a href="korea">Korea</a><br><a href="malaysia">Malaysia</a><br><a href="thailand">Thailand</a></p>'
$Pattern='(?<=>)\w+?(?=<)'

([Regex]::Matches($InputString,$Pattern)).Value

China

India

Korea

Malaysia

Thailand

edited May 9, 2018 at 13:52

answered May 9, 2018 at 13:46

qdl

112 bronze badges

Collectives™ on Stack Overflow

Extract multiple occurrences of a substring using Powershell

4 Answers 4

Comments

2 Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related