diff()
Here’s how to use diff() function.
A .diff()
Description:
Generate a new sequence by removing from the first sub-sequence of a sequence the members that exist in the other sub-sequences of the sequence.
Syntax:
A .diff()
Note:
Generally sequence A contains multiple sub-sequences. The function creates a new sequence by getting the difference of A’s first sub-sequence and the other sub-sequences, ensuring that the new sequence doesn’t include any member of the other sub-sequences.
The algorithm is to compute the difference between the first sub-sequence and the second one, then compute the difference between the result and the third sub-sequence, and so on and so forth.
Parameters:
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A |
A sequence whose members are sequences |
Return value:
A new sequence created by performing difference operations on A’s first sub-sequence and the other sub-sequences.
Example:
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A |
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1 |
=[[1,2,3,4,5],[3,7,8]].diff() |
[1,2,4,5] |
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2 |
=[[1,2,3],[3,2],1].diff() |
[] |
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3 |
=[[1,2,2,3],2].diff() |
[1,2,3] remove only one of the duplicate members |
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4 |
=demo.query("select top 2 * from EMPLOYEE") |
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5 |
=demo.query("select top 1 * from EMPLOYEE") |
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6 |
=[A4,A5].diff() |
Since A4 and A5 come from different table sequences and have different store addresses, so the same records are regarded as different members |
Note:
If the sub-sequences are record sequences, we can judge if they are duplicate by their store addresses.
Related functions:
A .diff( x )
Description:
Generate a sequence by first performing a certain computation on a given sequence and then removing from the resulting sequence’s first sub-sequence the members that exist in the other sub-sequences.
Syntax:
A.diff(x)
Note:
Generally sequence A contains multiple sub-sequences. The function loops through each sub-sequence of A to compute expression x and get the difference of the resulting sequence’s first sub-sequence and the other sub-sequences, ensuring that the difference result doesn’t include any member of the other sub-sequences.
The algorithm is to compute the difference between the first sub-sequence and the second one, then compute the difference between the result and the third sub-sequence, and so on and so forth.
Parameters:
|
A |
A sequence whose members are sequences |
|
x |
An expression that returns a sequence |
Return value:
A sequence
Example:
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A |
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1 |
=demo.query("select * from EMPLOYEE where GENDER = 'M' order by NAME") |
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2 |
=demo.query("select * from EMPLOYEE where GENDER = 'F' order by NAME") |
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3 |
=[A1,A2].diff(~.(NAME)) |
Remove only one of the duplicate members |
Related functions: