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APPEND procedure

Appends a list of vectors of the compatible types (R.W. Payne).

Options

NEWVECTOR = variate, factor or text Vector to store the appended values; by default uses the first vector of the OLDVECTOR list
FREPRESENTATION = string token How to match the values of old factors (levels, labels, ordinals, renumbered); default leve
GROUPS = factor Factor to represent the OLDVECTOR to which each unit originally belonged

Parameter

OLDVECTOR = variates, factors, texts or scalars Values to be appended

Description

APPEND provides a convenient way of taking the values from several variates, factors, scalars, or texts and appending (i.e. copying) them into a single variate, factor or text.

The variates, factors, scalars, and texts whose values are to be appended are specified by the OLDVECTOR parameter, and the NEWVECTOR option supplies the variate, factor or text to store the appended values. If NEWVECTOR is omitted, the values are placed into the first OLDVECTOR (but it must not be a scalar). Also, the type of the NEWVECTOR is taken from the first OLDVECTOR, if it has not already been defined.
The NEWVECTOR will contain all the values of the first OLDVECTOR, then all those from the second, and so on. The old vectors can thus contain different numbers of values, but they must be of compatible types. Texts can receive values from any type of OLDVECTOR, with the values of variates, factors scalars first being formed into texts using the TXCONSTRUCT directive. However, variates cannot receive values from texts.

Factors can receive values from any type, subject to the setting of the FREPRESENTATION option, described below. Variates, texts and scalars are first formed into factors, using the GROUPS directive, and the values are then transferred into the new factor. A factor formed from a text will therefore have both levels and labels, but those formed from variates or scalars will have only levels.

The FREPRESENTATION option indicates how the levels of factors are matched amongst the old factors. If this is set to labels and the levels of the old factors are compatible (that is if each label corresponds to the same level in all the old factors), then the level definitions are transferred to the new factor; if not, the levels are defined to be the default values 1, 2… and a warning is printed. Similarly, with the default setting FREPRESENTATION=levels, the labels are retained if they are compatible, but no warning is printed if they are not. For FREPRESENTATION=ordinals, the levels of all the factors are taken as the ordinal values 1, 2… (and no labels are defined). Finally, the renumbered setting assumes that the old factors all have independent sets of levels, and renumbers these from one upwards for the first factor, from number of levels of the first factor plus one upwards for the second factor, and so on; the new factor will thus have a different level for every level of the original factors.

The GROUPS option allows a factor to be formed indicating the OLDVECTOR to which each unit of the appended vector originally belonged. The levels are labelled by the identifier of the corresponding OLDVECTOR. This factor could be used in the CONDITION option of the SUBSET procedure subsequently to recover the values of the original vectors.

Options: NEWVECTOR, FREPRESENTATION, GROUPS.
Parameter: OLDVECTOR.

Method

APPEND defines the lengths and all other relevant attributes of the NEWVECTOR and then uses EQUATE to transfer the values.

Action with RESTRICT

See also

Directive: EQUATE.
Procedures: STACK, VEQUATE.
Commands for: Calculations and manipulation.

Example

CAPTION 'APPEND examples'; STYLE=meta
APPEND  [NEWVECTOR=Newvar] !(1...3),!(11...12),!(21)
APPEND  [NEWVECTOR=Newtext] !t(a,b,c),!t(d,e),!t(f)
PRINT   Newvar,Newtext

FACTOR  [LEVELS=3; VALUES=3,2,1] F1
FACTOR  [LEVELS=!(11,12); VALUES=12,11] F2
FACTOR  [LEVELS=!(21...23); VALUES=21] F3
" old factors only have levels: match by levels "
APPEND  [NEWVECTOR=Newfac1; GROUPS=Oldvec] F1,F2,F3
" old factors only have levels: match by ordinals "
APPEND  [NEWVECTOR=Newfac2; FREPRESENTATION=ordinals] F1,F2,F3
" old factors only have levels: renumber "
APPEND  [NEWVECTOR=Newfac3; FREPRESENTATION=renumbered] F1,F2,F3
PRINT   Oldvec,Newfac1,Newfac2,Newfac3

FACTOR  [LEVELS=3; LABELS=!t(a,b,c); VALUES=3,2,1] F1
FACTOR  [LEVELS=!(11,12); LABELS=!t(d,e); VALUES=12,11] F2
FACTOR  [LEVELS=!(21...23); LABELS=!t(f,g,h); VALUES=21] F3
" old factors only have labels and compatible levels: matching by levels "
APPEND  [NEWVECTOR=Newfac1] F1,F2,F3
" old factors only have labels and compatible levels: matching by labels "
APPEND  [NEWVECTOR=Newfac2; FREPRESENTATION=labels] F1,F2,F3
PRINT   2(Newfac1,Newfac2); FREPRESENTATION=labels,levels

FACTOR  [LEVELS=3; LABELS=!t(a,b,c); VALUES=3,2,1] F1
FACTOR  [LEVELS=!(11,12); LABELS=!t(d,e); VALUES=12,11] F2
FACTOR  [LEVELS=3; LABELS=!t(f,g,h); VALUES=1] F3
" old factors only have labels and incompatible levels: matching by levels "
APPEND  [NEWVECTOR=Newfac1] F1,F2,F3
" old factors only have labels and incompatible levels: matching by labels "
APPEND  [NEWVECTOR=Newfac2; FREP=labels] F1,F2,F3
PRINT   2(Newfac1,Newfac2); FREPRESENTATION=labels,levels
Updated on January 12, 2022

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