annotations              package:memisc              R Documentation

_A_d_d_i_n_g _A_n_n_o_t_a_t_i_o_n_s _t_o _O_b_j_e_c_t_s

_D_e_s_c_r_i_p_t_i_o_n:

     Annotations, that is, objects of class '"annotation"', are
     character vectors with all their elements named. Only one method
     is defined for this subclass of character vectors, a method for
     'show', that shows the annotation in a nicely formatted way.
     Annotations of an object can be obtained via the function
     'annotation(x)' and can be set via 'annotation(x)<-value'.

     Elements of an annotation with names '"description"' and
     '"wording"' have a special meaning. The first kind can be obtained
     and set via 'description(x)' and 'description(x)<-value', the
     second kind can be obtained via 'wording(x)' and
     'wording(x)<-value'. '"description"' elements are used in way the
     "variable labels" are used in SPSS and Stata. '"wording"' elements
     of annotation objects are meant to contain the question wording of
     a questionnaire item represented by an '"item"' objects. These
     elements of annotations are treated in a special way in the output
     of the 'coodbook' function.

_U_s_a_g_e:

     annotation(x)
     ## S4 method for signature 'ANY':
     annotation(x)
     ## S4 method for signature 'item':
     annotation(x)
     ## S4 method for signature 'data.set':
     annotation(x)
     annotation(x)<-value
     ## S4 replacement method for signature 'ANY, character':
     annotation(x)<-value
     ## S4 replacement method for signature 'item, annotation':
     annotation(x)<-value
     ## S4 replacement method for signature 'vector,
     ##   annotation':
     annotation(x)<-value

     description(x)
     description(x)<-value

     wording(x)
     wording(x)<-value

     ## S4 method for signature 'data.set':
     description(x)
     ## S4 method for signature 'importer':
     description(x)

_A_r_g_u_m_e_n_t_s:

       x: an object

   value: a character or annotation object

_V_a_l_u_e:

     'annotation(x)' returns an object of class '"annotation"', which
     is a named character. 'description(x)' and 'wording(x)' each
     usually return a character string. If 'description(x)' is applied
     to a 'data.set' or an 'importer' object, however, a character
     vector is returned, which is named after the variables in the data
     set or the external file.

_E_x_a_m_p_l_e_s:

     vote <- sample(c(1,2,3,8,9,97,99),size=30,replace=TRUE)
     labels(vote) <- c(Conservatives         =  1,
                         Labour                =  2,
                         "Liberal Democrats"   =  3,
                         "Don't know"          =  8,
                         "Answer refused"      =  9,
                         "Not applicable"      = 97,
                         "Not asked in survey" = 99
                         )
     missing.values(vote) <- c(97,99)
     description(vote) <- "Vote intention"
     wording(vote) <- "If a general election would take place next tuesday,
                         the candidate of which party would you vote for?"
     annotation(vote)
     annotation(vote)["Remark"] <- "This is not a real questionnaire item, of course ..."
     codebook(vote)

