Regular expressions help with HTML source code
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I'm looking to parse through some HTML source code to pull information from the Wall Street Journal. I need to pull the price of the following commodities: the 4 domestic crude oil spot prices, copper, aluminum, cotton, and cocoa
I'm having some trouble with getting regexp to work the way I want it to.
what string expression would you use to pull out the middle (bold) price listed? If the value is n.a., it's okay if it just returns 'n.a.' or its equivalent.
I tried a variety of methods and I couldn't get it to work.
Could someone show an example of the string he or she would use for extracting the price?
Thanks!
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Accepted Answer
Cedric
on 12 Mar 2013
Edited: Cedric
on 12 Mar 2013
>> buffer = urlread('http://online.wsj.com/mdc/public/page/2_3023-cashprices.html');
>> item = 'West Texas Intermediate, Cushing' ;
>> pattern = [item, '.*?*(?<prefix>.*?)(?<price>[\d\.]*)*'] ;
>> tokens = regexp(buffer, pattern, 'names') ;
tokens =
prefix: ''
price: '92.06'
>> item = 'London fixing, spot price' ;
>> pattern = [item, '.*?*(?<prefix>.*?)(?<price>[\d\.]*)*'] ;
>> tokens = regexp(buffer, pattern, 'names') ;
tokens =
prefix: '£' % Code, but the forum renders it.
price: '19.4273'
Cheers,
Cedric
Note that a . is returned for n.a. entries.
EDIT 1: corrected pattern thank to Walter's comment about pound-signs.
EDIT 2: updated with named tokens so we get the prefix (e.g. pound-sign).
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More Answers (1)
Walter Roberson
on 11 Mar 2013
'^<b>.*?\d+(\.\d+)?<\\b>$'
This should allow for the currency symbol, and for the possibility that the decimal point and following digits are not there. The only real "trick" here is the use of .*? to indicate the minimum expansion of repeated . (i.e., match any one character) where .* by itself is "greedy" and would match as many characters as possible.
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