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How to use custom separator for end of itemset and sequence in PrefixSpan?
Posted by:
Huang
Date: May 25, 2020 11:22PM
How to use custom separator for end of itemset and sequence instead of -1 and -2 in PrefixSpan?
Re: How to use custom separator for end of itemset and sequence in PrefixSpan?
Posted by:
webmasterphilfv
Date: May 26, 2020 01:57AM
Hi,
1) If you have an input file where other separators are used instead of -1 and -2 and you want to use SPMF, then you could just open the file in a text editor and replace the separators by -1 and -2 using the "find and replace" function.
Another way is to write a small program using any programming language to convert your file.
2) Now, if you want to see a different type of separator in the output file, then you could check the documentation of prefixspan:
http://www.philippe-fournier-viger.com/spmf/PrefixSpan.php
There is an example input file like this:
@CONVERTED_FROM_TEXT
@ITEM=1=apple
@ITEM=2=orange
@ITEM=3=tomato
@ITEM=4=milk
@ITEM=5=bread
@ITEM=6=noodle
@ITEM=7=rice
@ITEM=-1=|
1 -1 1 2 3 -1 1 3 -1 4 -1 3 6 -1 -2
1 4 -1 3 -1 2 3 -1 1 5 -1 -2
5 6 -1 1 2 -1 4 6 -1 3 -1 2 -1 -2
5 -1 7 -1 1 6 -1 3 -1 2 -1 3 -1 -2
and then the result file would look like this:
apple | #SUP: 4
orange | #SUP: 4
tomato | #SUP: 4
apple | orange | #SUP: 4
As you can see in the above results, the -1 separator has been replace by | in the output file.
But this feature works in the GUI of SPMF.
3) If you want to modify the code of PrefixSpan andyou are a bit familiar with java, it is not very hard and you could find the -1 and -2 in the code of PrefixSpan and replace them by something else.
----
So that is the main idea. It could a good idea maybe to add a feature in SPMF to let the user choose a separator. This has not been implemented. But it could be a good idea for the future.
Best regards,
Philippe
1) If you have an input file where other separators are used instead of -1 and -2 and you want to use SPMF, then you could just open the file in a text editor and replace the separators by -1 and -2 using the "find and replace" function.
Another way is to write a small program using any programming language to convert your file.
2) Now, if you want to see a different type of separator in the output file, then you could check the documentation of prefixspan:
http://www.philippe-fournier-viger.com/spmf/PrefixSpan.php
There is an example input file like this:
@CONVERTED_FROM_TEXT
@ITEM=1=apple
@ITEM=2=orange
@ITEM=3=tomato
@ITEM=4=milk
@ITEM=5=bread
@ITEM=6=noodle
@ITEM=7=rice
@ITEM=-1=|
1 -1 1 2 3 -1 1 3 -1 4 -1 3 6 -1 -2
1 4 -1 3 -1 2 3 -1 1 5 -1 -2
5 6 -1 1 2 -1 4 6 -1 3 -1 2 -1 -2
5 -1 7 -1 1 6 -1 3 -1 2 -1 3 -1 -2
and then the result file would look like this:
apple | #SUP: 4
orange | #SUP: 4
tomato | #SUP: 4
apple | orange | #SUP: 4
As you can see in the above results, the -1 separator has been replace by | in the output file.
But this feature works in the GUI of SPMF.
3) If you want to modify the code of PrefixSpan andyou are a bit familiar with java, it is not very hard and you could find the -1 and -2 in the code of PrefixSpan and replace them by something else.
----
So that is the main idea. It could a good idea maybe to add a feature in SPMF to let the user choose a separator. This has not been implemented. But it could be a good idea for the future.
Best regards,
Philippe