delete()

Read(2482) Label: delete,

Here’s how to use delete() function.

T .delete()

Description:

Delete specified records from a table sequence.

Syntax:

T.delete(k)

Delete the kth record

T.delete(p)

Delete records whose ordinal numbers exist in p

T.delete(A)

Delete records that exist in sequence A

Note:

The function deletes the specified records from table sequence T, and automatically updates the index, if any, and checks distinctness. The deleted records will be always saved in the delete buffer.

Parameter:

T

A table sequence

k

A positive integer, which specifies the position of a record to be deleted

p

An integer sequence with the length of n, which specifies the positions of the records to be deleted

A

A sequence, which specifies the records to be deleted

Option:

@n

Return the deleted record or a record sequence of the deleted records

Return value:

Table sequence

Example:

 

A

 

1

=demo.query("select * from EMPLOYEE")

 

2

=A1.delete(1)

Delete the first record

3

=A1.delete([2,4,6])

Delete the second, the forth and the sixth records.

4

=A1.select(EID>5)

 

5

=A1.delete(A4)

Delete the records whose EID is more than 5.

6

=A1.delete@n(1)

Return the deleted record

Note:

We use the store address, instead of the field names or field values, to judge whether the records specified by A exist in T. So to delete the specified records, we generally use the function T.delete(T.select(…)) to locate them.

Related function:

T.modify()

T.insert()

A.delete()

A. delete()

Description:

Delete specified members from a sequence.

Syntax:

A.delete(k)

Delete the kth member

A.delete(p)

Delete members whose ordinal numbers exist in p; count backward when a member of sequence p is less than 0

Note:

The function deletes the kth member or the members whose ordinal numbers exist in p from sequence A, and automatically updates the index, if any, and checks distinctness.

Parameter:

A

A sequence

k

A positive integer that indicates the position of a member to be deleted in the sequence

p

An integer sequence with the length of n that specifies the positions of the members to be deleted

Option:

@n

Return the deleted record or a record sequence of the deleted records

Return value:

A sequence

Example:

 

A

 

1

=["a","c","d","e","f"]

 

2

=A1.delete([2,4,5])

[a,d]

3

=demo.query("select * from STUDENTS")

 

4

=A3.delete@n(2)

Return the deleted record

 

5

=["a","c","d","e","f"].delete([3,-5])

Count backward to get the value  [c,e,f] since one member of the sequence parameter is less than 0

Related function:

A.insert()

A.modify()

T.delete()