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    Names: »dm.man«

└─⟦a0efdde77⟧ Bits:30001252 EUUGD11 Tape, 1987 Spring Conference Helsinki
    └─⟦this⟧ »EUUGD11/stat-5.3/eu/stat/doc/dm.man« 

TextFile

DM(1)                              |STAT                  November 26, 1985

NAME
     dm - data manipulation with conditional transformations

SYNOPSIS
     dm [Efile] [expressions]

DESCRIPTION
     _▶08◀d_▶08◀m is a data manipulating program for column extraction from files,
     possibly based on conditions, and production of algebraic combinations
     of columns.  _▶08◀d_▶08◀m reads whitespace separated fields on each line of its
     input.  _▶08◀d_▶08◀m takes a series of expressions, and for each line of the
     input, _▶08◀d_▶08◀m reevaluates and prints the values of those expressions.
     Numerical values of fields on a line can be accessed by the letter 'x'
     followed by a column number.  Character strings can be accessed by the
     letter 's' followed by a column number.  For example, for the input
     line:
                                    12  45.2
     s1 is the string '12', x2 is the number 45.2 (which is not the same as
     s2, the string '45.2').

     _▶08◀C_▶08◀o_▶08◀l_▶08◀u_▶08◀m_▶08◀n _▶08◀E_▶08◀x_▶08◀t_▶08◀r_▶08◀a_▶08◀c_▶08◀t_▶08◀i_▶08◀o_▶08◀n. Columns are extracted with string expressions.  To
     extract the 3rd, 8th, 1st and 2nd columns (in that order) from "file,"
     one would type:
                          dm  s3  s8  s1  s2  <  file

     _▶08◀A_▶08◀l_▶08◀g_▶08◀e_▶08◀b_▶08◀r_▶08◀a_▶08◀i_▶08◀c _▶08◀T_▶08◀r_▶08◀a_▶08◀n_▶08◀s_▶08◀f_▶08◀o_▶08◀r_▶08◀m_▶08◀a_▶08◀t_▶08◀i_▶08◀o_▶08◀n_▶08◀s. To print, in order, the sum of the columns
     1 and 2, the difference of columns 3 and 4, and the square root of the
     sum of squares of the 1st and 3rd columns, one could type the command:
                    dm  "x1+x2"  "x3-x4"  "(x1*x1+x3*x3)^.5"
     There are the usual mathematical functions that allow expressions
     like:
            dm  "exp(x1) + log(log(x2))"  "floor (x1/x2)"  "sin x1"

     _▶08◀T_▶08◀e_▶08◀s_▶08◀t_▶08◀i_▶08◀n_▶08◀g _▶08◀C_▶08◀o_▶08◀n_▶08◀d_▶08◀i_▶08◀t_▶08◀i_▶08◀o_▶08◀n_▶08◀s. Expressions can be conditionally evaluated by
     comparing values.  To print the ratio of x1 and x2, and check the
     value of x2 before division and print 'error' if x2 is 0, one could
     type:
                     dm "if x2 = 0 then 'error' else x1/x2"
     To extract lines in which two columns are the same string, say the 5th
     and 2nd, one would type:
                      dm "if s5 = s2 then INPUT else NEXT"

     _▶08◀O_▶08◀t_▶08◀h_▶08◀e_▶08◀r _▶08◀F_▶08◀e_▶08◀a_▶08◀t_▶08◀u_▶08◀r_▶08◀e_▶08◀s. _▶08◀d_▶08◀m has comparison, algebraic, and logical operators,
     and special variables to take control in exceptional conditions.
     These include: INPUT, the current input line in string form; INLINE,
     the current input line number; N, the field count in INPUT; SUM, the
     sum of the numbers in INPUT; RAND, a uniform random number different
     for each line; NIL, an expression that causes no output; NEXT, which
     terminates evaluation on INPUT and goes to the next line; and EXIT,
     which terminates all processing.

LIMITS
     Input fields longer than 15 characters are truncated silently.  The
     number of input columns, output expressions, and expression constants
     are limited to 100.

SEE ALSO
     The DM Manual in The |STAT Handbook