Chapter 4 Sequence

Read(347) Label: sequence,

This chapter lists code examples of handling sequences, including Check if it is a sequence, Get a sequence member or a sub-sequence in reverse direction, Get a sequence member or a sub-sequence in cycles, Get a sub-sequence but report no error if a specified position is beyond range, Generate a fixed-length sequence consisting of duplicate members, Duplicate a sequence (repeatedly) to generate a new sequence, Generate a continuous interger sequence, Exchange positions of member groups of a sequence, Insert one or multiple members to a sequence, Delete one or multiple members from a sequence, Modify one or multiple members of a sequence, Modify sequence member(s) at specified position(s) and supply values at the beyond-range position(s), Insert a sequence as a member into another sequence, Compare sequences in ASCII dictionary mode, Get inversed sequence, Get & count unique members in a sequence, Stretch sequence to specified length and Sequence-related logic operations.

4.1 Check if it is a sequence

 

A

 

1

=ifa([1,2,3])

true

2

=ifa(123)

false

 

4.2 Get a sequence member and a sub-sequence in reverse direction

 

A

 

1

=[1,2,3,4,5,6].m(-3)

4

2

=[1,2,3,4,5,6].m([-2,-3])

[5,4]

 

4.3 Get a sequence member or a sub-sequence in cycles

 

A

 

1

[1,2,3,4,5,6]

 

2

=A1.m@r(10)

4

3

=A1.m@r([1,5,10])

[1,5,4]

 

4.4 Get a sub-sequence but report no error if a specified position is beyond range

 

A

 

1

=[1,2,3,4,5,6].m@0([10,1,4,5])

[1,4,5];out-of-range members are not included

 

4.5 Generate a fixed-length sequence consisting of same members

 

A

 

1

=5*[1]

[1,1,1,1,1]

2

=3.("a")

[a,a,a]

 

4.6 Duplicate a sequence (repeatedly) to generate a new sequence

 

A

 

1

=[1,2,3]

 

2

=3*A1

[1,2,3,1,2,3,1,2,3]

 

4.7 Generate a continuous integer sequence

 

A

 

1

=to(8)

[1,2,3,4,5,6,7,8]

2

=to(3,5)

The result is [3,4,5] which is from 3 to 5

3

=to@s(3,5)

The result is [3,4,5,6,7] which counts 5 numbers forward from 3

4

=to@s(7,-3)

The result is [7,6,5]

 

4.8 Exchange positions of member groups of a sequence

 

A

 

1

=[1,2,3,4,5,6,7,8].swap([2,3,4],[6,7])

[1,6,7,5,2,3,4,8]

 

4.9 Insert one or multiple members to a sequence

 

A

 

1

=[1,2,3,4].insert(0,5)

[1,2,3,4,5]. Insert the members at the end

2

=[1,2,3,4].insert(1,5)

[5,1,2,3,4]. Insert the members at the beginning

3

=[1,2,3,4].insert(3,[5,6])

[1,2,5,6,3,4]. Insert multiple members

4

[1,2,3,4]

[1,2,3,5,6,4], the new A4 after A5 is executed

5

=A4.insert@n(4,[5,6])

[5,6], return the newly-added member

 

4.10 Delete one or multiple members from a sequence

 

A

 

1

=[11,12,13,14].delete(2)

Delete one member and the result is [11,13,14]

2

=[11,12,13,14].delete([2,4])

Delete multiple members and the result is [11,13]

 

4.11 Modify one or multiple members of a sequence

 

A

 

1

=[11,12,13,14]

 

2

>A1(2)=6

The value in A1 is [11,6,13,14]

3

>A1([3,4])=[7,8]

The value in A1 is [11,6,7,8]

4

>A1.run(~=~%2)

The value in A1 is [1,0,1,0]

 

4.12 Modify sequence member(s) at specified position(s) and supply values at beyond-range position(s)

 

A

 

1

=[11,12,13,14,15].modify(2,6)

[11,6,13,14,15]

2

=[11,12,13,14,15].modify(10,10)

[11,12,13,14,15,null,null,null,null,10]

3

=[11,12,13,14,15].modify(2,[7,8,9])

[11,7,8,9,15]

 

4.13 Insert a sequence as a member into another sequence

 

A

 

1

[1,2,3,4]

 

2

[5,6,7,8]

 

3

=A1.insert(3,[A2])

[1,2,[5,6,7,8],3,4]

 

4.14 Compare sequences in ASCII dictionary mode

 

A

 

1

=cmp(["a","b","c"],["d","e","f"])

-1, ASCII code for "a" is 1 less than that for "d"

2

=cmp(["d","b","c"],["a","e","f"])

1, ASCII code for "d" is 1 more than that for "a"

4.15 Get inversed sequence

 

A

 

1

[1,3,5,2,4,6]

 

2

=A1.rvs()

[6,4,2,5,3,1]

 

4.16 Get & count unique members in a sequence

 

A

 

1

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

 

2

=A1.id()

[a,b,c,d,e,f], remove duplicates and sort members

3

=A1.id@o()

[a,c,d,e,f,a,b], remove neighboring duplicate only

4

=A1.id@u()

[a,c,d,e,f,b], remove duplicates but won’t perform sort

5

=A1.icount()

6, count members after duplicates are deleted

6

=A1.icount@o()

7, count members after neighboring duplicates are deleted

 

4.17 Stretch sequence to specified length

 

A

 

1

[a,b,c,d,e,f]

 

2

=A1.pad(null,9)

[a,b,c,d,e,f,null,null,null], add members on the right side

3

=A1.pad@l(null,9)

[null,null,null,a,c,d,e,f,a,b], add members on the left side

 

4.18 Sequence-related logic operations

 

A

 

1

=[2<10,3>4,1!=1]

[true,false,false]

2

=A1.cand()

false

3

=[20,1<2].cand()

true

4

=[null,1<2].cand()

false

5

=[1!=1,3<2].cor()

false