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How to delete a ets entry based on non key part

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0

I have a etc table ‘table’ as key,[val1,val2]
I selected this data from the table using

ets:select(table,[‘$1','$2',[],['$$']]). 
 [[key,["val1",<<"12">>]],
 [key,["val2",<<"6">>]],
 [key,["val3",<<"16">>]]]

I want to delete a entry matching the part [val1,val2] using this

ets:select_delete(table,[‘$1','$2',['==','$2',["val1",<<"12">>]],['$$']]).
 0

But still when I run select again I get

ets:select(table,[‘$1','$2',[],['$$']]). 
 [[key,["val1",<<"12">>]],
 [key,["val2",<<"6">>]],
 [key,["val3",<<"16">>]]]

How can I delete this entry based on the non key part?

erlang

share|improve this question

edited Mar 8 at 8:28

abhishek ranjan

asked Mar 8 at 8:22

abhishek ranjanabhishek ranjan

98111

add a comment | 

0

I have a etc table ‘table’ as key,[val1,val2]
I selected this data from the table using

ets:select(table,[‘$1','$2',[],['$$']]). 
 [[key,["val1",<<"12">>]],
 [key,["val2",<<"6">>]],
 [key,["val3",<<"16">>]]]

I want to delete a entry matching the part [val1,val2] using this

ets:select_delete(table,[‘$1','$2',['==','$2',["val1",<<"12">>]],['$$']]).
 0

But still when I run select again I get

ets:select(table,[‘$1','$2',[],['$$']]). 
 [[key,["val1",<<"12">>]],
 [key,["val2",<<"6">>]],
 [key,["val3",<<"16">>]]]

How can I delete this entry based on the non key part?

erlang

share|improve this question

edited Mar 8 at 8:28

abhishek ranjan

asked Mar 8 at 8:22

abhishek ranjanabhishek ranjan

98111

add a comment | 

I have a etc table ‘table’ as key,[val1,val2]
I selected this data from the table using

ets:select(table,[‘$1','$2',[],['$$']]). 
 [[key,["val1",<<"12">>]],
 [key,["val2",<<"6">>]],
 [key,["val3",<<"16">>]]]

I want to delete a entry matching the part [val1,val2] using this

ets:select_delete(table,[‘$1','$2',['==','$2',["val1",<<"12">>]],['$$']]).
 0

But still when I run select again I get

ets:select(table,[‘$1','$2',[],['$$']]). 
 [[key,["val1",<<"12">>]],
 [key,["val2",<<"6">>]],
 [key,["val3",<<"16">>]]]

How can I delete this entry based on the non key part?

erlang

share|improve this question

edited Mar 8 at 8:28

abhishek ranjan

asked Mar 8 at 8:22

abhishek ranjanabhishek ranjan

98111

ets:select(table,[‘$1','$2',[],['$$']]). 
 [[key,["val1",<<"12">>]],
 [key,["val2",<<"6">>]],
 [key,["val3",<<"16">>]]]

ets:select_delete(table,[‘$1','$2',['==','$2',["val1",<<"12">>]],['$$']]).
 0

ets:select(table,[‘$1','$2',[],['$$']]). 
 [[key,["val1",<<"12">>]],
 [key,["val2",<<"6">>]],
 [key,["val3",<<"16">>]]]

share|improve this question

edited Mar 8 at 8:28

abhishek ranjan

asked Mar 8 at 8:22

abhishek ranjanabhishek ranjan

98111

share|improve this question

edited Mar 8 at 8:28

abhishek ranjan

asked Mar 8 at 8:22

abhishek ranjanabhishek ranjan

98111

asked Mar 8 at 8:22

abhishek ranjanabhishek ranjan

98111

asked Mar 8 at 8:22

abhishek ranjanabhishek ranjan

98111

1 Answer
1

active

oldest

votes

0

The ets:select_delete documentation says:

The match specification has to return the atom true if the object is to be deleted. No other return value gets the object deleted. So one cannot use the same match specification for looking up elements as for deleting them.

So try this:

ets:select_delete(table,['$1','$2',['==','$2',["val1",<<"12">>]],true]).

ets:select_delete returns the number of records it deleted, so hopefully it should return 1 this time.

share|improve this answer

edited Mar 8 at 9:45

answered Mar 8 at 9:36

legoscialegoscia

29.6k1185116

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I used ets:select_delete(table,[‘$1','$2',['==','$2',["val1",<<"12">>]],true]). which gives a ` * 1: illegal character ` error.
  
  – abhishek ranjan
  Mar 8 at 9:44
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Oops, a smart quotation mark crept in. I edited the answer, please try again. (That is, the single quote right before $1 was not a "real" single quote.)
  
  – legoscia
  Mar 8 at 9:46
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I tried the updated command but I got this ` ets:select_delete(table,['$1','$2',['==','$2',["val1",<<"12">>]],true]). ** exception error: bad argument in function ets:select_delete/2 called as ets:select_delete(table, ['$1','$2',['==','$2',["val1",<<"12">>]],true])` Plus the ets:select/2 command also give the same error now.
  
  – abhishek ranjan
  Mar 8 at 9:58
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I think by running the command with atom 'true' my table got deleted instead(I don't know how though).
  
  – abhishek ranjan
  Mar 8 at 10:00
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  If you're creating the table in the shell, and then run something that crashes, the table will be deleted as it was owned by the shell process that crashed.
  
  – legoscia
  Mar 8 at 10:06
  

  
  
  
  

 | 
show 1 more comment

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0

The ets:select_delete documentation says:

The match specification has to return the atom true if the object is to be deleted. No other return value gets the object deleted. So one cannot use the same match specification for looking up elements as for deleting them.

So try this:

ets:select_delete(table,['$1','$2',['==','$2',["val1",<<"12">>]],true]).

ets:select_delete returns the number of records it deleted, so hopefully it should return 1 this time.

share|improve this answer

edited Mar 8 at 9:45

answered Mar 8 at 9:36

legoscialegoscia

29.6k1185116

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I used ets:select_delete(table,[‘$1','$2',['==','$2',["val1",<<"12">>]],true]). which gives a ` * 1: illegal character ` error.
  
  – abhishek ranjan
  Mar 8 at 9:44
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Oops, a smart quotation mark crept in. I edited the answer, please try again. (That is, the single quote right before $1 was not a "real" single quote.)
  
  – legoscia
  Mar 8 at 9:46
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I tried the updated command but I got this ` ets:select_delete(table,['$1','$2',['==','$2',["val1",<<"12">>]],true]). ** exception error: bad argument in function ets:select_delete/2 called as ets:select_delete(table, ['$1','$2',['==','$2',["val1",<<"12">>]],true])` Plus the ets:select/2 command also give the same error now.
  
  – abhishek ranjan
  Mar 8 at 9:58
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I think by running the command with atom 'true' my table got deleted instead(I don't know how though).
  
  – abhishek ranjan
  Mar 8 at 10:00
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  If you're creating the table in the shell, and then run something that crashes, the table will be deleted as it was owned by the shell process that crashed.
  
  – legoscia
  Mar 8 at 10:06
  

  
  
  
  

 | 
show 1 more comment

0

The ets:select_delete documentation says:

The match specification has to return the atom true if the object is to be deleted. No other return value gets the object deleted. So one cannot use the same match specification for looking up elements as for deleting them.

So try this:

ets:select_delete(table,['$1','$2',['==','$2',["val1",<<"12">>]],true]).

ets:select_delete returns the number of records it deleted, so hopefully it should return 1 this time.

share|improve this answer

edited Mar 8 at 9:45

answered Mar 8 at 9:36

legoscialegoscia

29.6k1185116

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I used ets:select_delete(table,[‘$1','$2',['==','$2',["val1",<<"12">>]],true]). which gives a ` * 1: illegal character ` error.
  
  – abhishek ranjan
  Mar 8 at 9:44
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Oops, a smart quotation mark crept in. I edited the answer, please try again. (That is, the single quote right before $1 was not a "real" single quote.)
  
  – legoscia
  Mar 8 at 9:46
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I tried the updated command but I got this ` ets:select_delete(table,['$1','$2',['==','$2',["val1",<<"12">>]],true]). ** exception error: bad argument in function ets:select_delete/2 called as ets:select_delete(table, ['$1','$2',['==','$2',["val1",<<"12">>]],true])` Plus the ets:select/2 command also give the same error now.
  
  – abhishek ranjan
  Mar 8 at 9:58
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I think by running the command with atom 'true' my table got deleted instead(I don't know how though).
  
  – abhishek ranjan
  Mar 8 at 10:00
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  If you're creating the table in the shell, and then run something that crashes, the table will be deleted as it was owned by the shell process that crashed.
  
  – legoscia
  Mar 8 at 10:06
  

  
  
  
  

 | 
show 1 more comment

The ets:select_delete documentation says:

The match specification has to return the atom true if the object is to be deleted. No other return value gets the object deleted. So one cannot use the same match specification for looking up elements as for deleting them.

So try this:

ets:select_delete(table,['$1','$2',['==','$2',["val1",<<"12">>]],true]).

ets:select_delete returns the number of records it deleted, so hopefully it should return 1 this time.

share|improve this answer

edited Mar 8 at 9:45

answered Mar 8 at 9:36

legoscialegoscia

29.6k1185116

ets:select_delete(table,['$1','$2',['==','$2',["val1",<<"12">>]],true]).

share|improve this answer

edited Mar 8 at 9:45

answered Mar 8 at 9:36

legoscialegoscia

29.6k1185116

answered Mar 8 at 9:36

legoscialegoscia

29.6k1185116

answered Mar 8 at 9:36

legoscialegoscia

29.6k1185116