[ int-constant | real-constant | logical-constant | string-constant | iarray-constant | rarray-constant | sarray-constant ]

• integers: -9999 12
• reals: 12.0 -0.00003 2.
• logicals: yes no
• strings: "I see M", "Backslash (\\) and quote (\")" "line1\nline2" or

  ## newlines are allowed between triple quotes, e.g.
  a = """
   A text with lines
  is also a string
  """

  Escape sequences which can be used inside strings:

  \a - bell 
  \b - backspace 
  \f - formfeed 
  \n - newline 
  \r - carriage return 
  \t - horizontal tab 
  \v - vertical tab 
  \\ - backslash 
  \" - double quote

• integer arrays: {2, -1, 6, 0} {-8, -1, 2} The comma is compulsory before a negative number, it can be skipped otherwise.
• real array: { -1.6 , 2.150 3., -160.} Real arrays can also contain "ND" (Not Defined) and other special values. The following special values:
  • ND (not defined)
  • >r_value
  • <r_value
  • INF : infinity
  • -INF : infinity
  To compare an array with special value use the Toreal function:

  read table csv "x_with_spec_values.csv" name="t"
  t.A == Toreal({"ND"})

  Option number in read table csv will convert empty fields into NDHowever not all functions support them, be careful. Example:

  show Toreal({"ND"}
  #
  # here we are changing 0. values to NDs
   group table t {1. 0. 2. 0.}
   idx = Index( t.A == 0.0 )
   t.A[ idx ] = Toreal( Sarray( Nof(idx), "ND" ) )

• string arrays: {"do","re","mi","fa","sol"} {"\n(newline), \t (tab)","\a (bell)"}
• selections (find a detailed description below):

a_hiv?.  a_1,2.  a_*.           # objects 
 a_h*.a   a_m1    a_*.!w2,w15,z* # molecules 
 a_1.*/2:15,18:26 a_/18,his*     # residues 
 a_//ca,c,n a_1.c a_/2:4/!h*     # atoms 
 v_//phi,psi      V_2//?vt*      # variables