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Component files

A component file (jfile) can be thought of as a boxed list stored in a file. An item of the boxed list on file is referred to as a component. The script jfiles.ijs provides the utilities for working with jfiles.

   load 'jfiles'
   f =. 'user\data.jf'
   jcreate f
1
   'first component' jappend f
0
   (1.5+i.2 3) jappend f
1
   ('asdf';23) jappend f
2 3
   (<'mum';'dad') jappend f
4

The jsize result gives file information, including the indexes of the first and last items.

   jsize f
0 5 1408 0
   jread f;0
+---------------+
|first component|
+---------------+
   jread f;1
+-----------+
|1.5 2.5 3.5|
|4.5 5.5 6.5|
+-----------+
   jread f;2
+----+
|asdf|
+----+
   jread f;3
+--+
|23|
+--+
   jread f;4
+---------+
|+---+---+|
||mum|dad||
|+---+---+|
+---------+
   'new' jreplace f;3
3
   jread f;i.5
+---------------+-----------+----+---+---------+
|first component|1.5 2.5 3.5|asdf|new|+---+---+|
|               |4.5 5.5 6.5|    |   ||mum|dad||
|               |           |    |   |+---+---+|
+---------------+-----------+----+---+---------+

Jfiles are documented in the J Online Documentation.

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