System Variable IO

From NARS2000
Jump to: navigation, search

⎕IO - Index Origin

Z←⎕IO returns the current value of the Index Origin.
Z is an integer vector containing the current value of ⎕IO. This is the lowest value of an array subscript, and is either 1 or 0.

⎕IO←0 set the lowest subscript of an array to 0.
⎕IO←1 sets the lowest subscript for arrays to 1


⎕IO determines the lowest subscript for arrays. The default is 1, but can be changed to 0. If an attempt is made to set ⎕IO to a value higher than 1, it is set to 1. If an attempt is made to set ⎕IO to a value loweer than 0, it is set to 0. Setting ⎕IO to anything other than a number causes a DOMAIN ERROR.

    ⎕IO    ⍝ default ⎕IO (quad IO) is 1 in a clear workspace
1
      ⍳5    ⍝ iota 5
1 2 3 4 5 

      ⎕IO←0     ⍝ Set index origin ⎕IO to 0 (zero)

      ⍳5   ⍝ iota 5 again but compare the results just below to just above
0 1 2 3 4
System Variables (A value may be assigned to these except for ⎕DM)
ALX CT DM DT ELX FC FEATURE FPC IC IO
LX PP PR PW RL SA WSID
Niladic System Functions (a value cannot be assigned to these)
A AV EM ET LC NNAMES NNUMS SYSID SYSVER T
TC TCBEL TCBS TCESC TCFF TCHT TCLF TCNL TCNUL TS
WA
Monadic or dyadic system functions (a value cannot be assigned to these)
AT CR DC DL DR EA EC ERROR ES EX
FMT FX MF NAPPEND NC NCREATE NERASE NINFO NL NLOCK
NREAD NRENAME NREPLACE NRESIZE NSIZE NTIE NUNTIE STOP TF TRACE
UCS VR
Note that quad functions and variables are case insensitive


See Also
System Commands System Variables and Functions Operators
Keyboard
A+S
Alt ¨ ¯ < > × ÷
Sh ~ ! @ # $ % ^ & * ( ) _ +
Key ` 1 2 3 4 5 6 7 8 9 0 - =
A+S
Alt ? π
Sh Q W E R T Y U I O P { } |
Key q w e r t y u i o p [ ] \
A+S §
Alt '
Sh A S D F G H J K L : "
Key a s d f g h j k l ; '
A+S
Alt
Sh Z X C V B N M < > ?
Key z x c v b n m , . /
NARS 2000 Lang
Tool
Bar
+ - × ÷ * ! ? |
= < >
~ § π .. ,
/ \ ¨ .
_ ¯ Ø b e g p r v x