How can I manipulate/extract info from the following table in J

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   ]data=:_3 ]\ 'Jack';23;178;'Rick';27;181;'Alice';41;178;'Mitch';31;184;'Paul';32;179
┌─────┬──┬───┐
│Jack │23│178│
├─────┼──┼───┤
│Rick │27│181│
├─────┼──┼───┤
│Alice│41│178│
├─────┼──┼───┤
│Mitch│31│184│
├─────┼──┼───┤
│Paul │32│179│
└─────┴──┴───┘

The first field is name, second is age and third is height in cm.

j
1 Answers

If you search for [j] table you'll find this question that yours is arguably a duplicate of, but it's easy to imagine that its answer wouldn't seem to apply to your data, so I've adapted the answer below:

   NB. Select names
   0 {"1 data
+----+----+-----+-----+----+
|Jack|Rick|Alice|Mitch|Paul|
+----+----+-----+-----+----+
   
   NB. test if name contains a 'k'
   +/"1 'k' e.~ 0 {::"1 data
1 1 0 0 0
   
   NB. select rows where the name contains a 'k'
   (+/"1 'k' e.~ 0 {::"1 data) # data
+----+--+---+
|Jack|23|178|
+----+--+---+
|Rick|27|181|
+----+--+---+
   (#~ [: +/"1 'k' e.~ 0&{::"1) data
+----+--+---+
|Jack|23|178|
+----+--+---+
|Rick|27|181|
+----+--+---+
   
   NB. select names where height > 180
   > 0{"1 (#~ 180 < 2&{::"1) data
Rick 
Mitch
   
   NB. get average age and height
   (+/%#) 1 2 pick"1 data
30.8 180
   
   NB. add a row
   is =: 4 : 'data =: data, (<x),y'
   years =: 1 : '<u'
   cm =: 1 : '<u'
   'Rebecca' is 24 years, 176 cm
... omitted ...
   'Gregory' is 37 years, 182 cm
... omitted ...
   load 'inverted'
   ,.&.> ifa data
+-------+--+---+
|Jack   |23|178|
|Rick   |27|181|
|Alice  |41|178|
|Mitch  |31|184|
|Paul   |32|179|
|Rebecca|24|176|
|Gregory|37|182|
+-------+--+---+

That last bit is from Inverted Tables, which has some advantages, probably the very least of which is that they echo less noisily.

user_8470990
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