User:Martin Kreuzer/Playground
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• Example: Parsing HTML
(Simple) Fork Example
Working this example step by step (sections* active are in regular print, rest is <f>faded</f>):
* Each section, taken isolated, may not neccessarily be valid J.
NB. dyadic case: <f>2 1 3</f> (<f>+ 4 <. >./ -</f> <./) 3 1 4 1 5 9 <f>NB.</f> get Min of y <f>2 1 3</f> (<f>+ 4 <.</f> >./ <f>- 1</f>) 3 1 4 1 5 9 <f>NB.</f> get Max of y <f>2 1 3</f> (<f>+ 4 <.</f> 9 - 1)<f> 3 1 4 1 5 9</f> <f>NB.</f> calc the difference <f>2 1 3</f> (<f>+</f> 4 <. 8)<f> 3 1 4 1 5 9</f> <f>NB.</f> take the lesser of 4 and 8 2 1 3 (+ 4)<f> 3 1 4 1 5 9</f> <f>NB.</f> add 4 to the list x 6 5 7 <f>NB.</f> result NB. monadic case: ∙∙∙∙ (+ 4) 3 1 4 1 5 9 <f>NB.</f> add 4 to the list y 7 5 8 5 9 13 <f>NB.</f> result
• Example: Parsing HTML
Given: Table Structure and Content.
mytable=: 0 : 0
<table ...>
<tr ...>-1----------row1----------------1-</tr>
<tr ...>-2----------row2-----------------------------2-</tr>
<tr ...>-3----------row3---------------------3-</tr>
</table>
)
dataypte mytable
literal
Task: Parse the table and pick content of Row2.
Remark: Script strings.ijs (providing dyadic verbs taketo and takeafter) is part of the J standard library.
y=. mytable; '<tr' takeafter y NB. that's aiming at Row1 ...>-1----------row1----------------1-</tr> <tr ...>-2----------row2-----------------------------2-</tr> <tr ...>-3----------row3---------------------3-</tr> </table> '<tr' takeafter(^:2) y NB. that's better, near Row2 ...>-2----------row2-----------------------------2-</tr> <tr ...>-3----------row3---------------------3-</tr> </table> '>' takeafter '<tr' takeafter(^:2) y NB. getting rid of tag closing -2----------row2-----------------------------2-</tr> <tr ...>------------row3---------------------3-</tr> </table> '</tr' taketo '>' takeafter '<tr' takeafter(^:2) y NB. Row2's content, as requested -2----------row2-----------------------------2-