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DELETE

Keyword Abbreviation Token (hex) Version(s) Classification
DELETE DE{Shift+L} E0 4.7 Command
CHAR CH{Shift+A} E0 3.5, 7.0 Command and Statement
DELETE DE{Shift+L} F7 3.5, 7.0 Command

  Syntax  
DELETE [ { firstLine [ - [ lastLine ] ] | - lastLine } ]
 
Parameters Type Legal Value(s) Default Value Note(s)
firstLine Literal integer
0 to 63999
 
lastLine Literal integer
0 to 63999, but
not less than firstLine
63999
 
 
  Purpose  
Program editing; Erase BASIC program line(s) from memory.

 
  Remarks  
DELETE uses the same Syntax as LIST (except for a different keyword, of course).  So if you have mastered LIST then DELETE should be a snap!
 
All program lines in memory (if any) are erased if no parameters are supplied.  This is almost like NEW, but variables are not cleared.
 
If parameters are supplied, they must be literal integer values; attempts to use a floating-point literal value, a variable, or a mathematical expression will generate SYNTAX ERROR.
 
  • If only firstLine is supplied, without the optional hyphen/minus (-), then only that specific line number is erased, if it exists (no error otherwise).
  • If only firstLine is supplied and is followed with a hyphen/minus, then all lines of the program greater or equal to firstLine (if any) are erased.
  • If only a hyphen/minus and lastLine is given, then all lines less than or equal to lastLine (if any) are erased.
 
If both parameters (firstLine and lastLine) are supplied, but lastLine is less than firstLine then nothing is erased and no error is generated (this doesn't seem very logical).  If firstLine is greater than the last line number of the program, or if lastLine is less than the first line number of the program, then nothing is deleted and no error is generated (this is quite logical).  Finally, if both parameters are given and firstLine is less than or equal to lastLine, then all program lines numbered from firstLine to lastLine (inclusive) are erased, if any exist in that range.
 
DELETE may only be used as a command in direct mode.  Attempting to use it as a statement in a program will generate DIRECT MODE ONLY ERROR.
 
Examples:
NEW

READY.
10 REM LINE 10
20 REM LINE 20
30 REM LINE 30
DELETE 22 : LIST

10 REM LINE 10
20 REM LINE 20
30 REM LINE 30

READY.
DELETE 25-

READY.
LIST

10 REM LINE 10
20 REM LINE 20

READY.
DELETE -15

READY.
LIST

20 REM LINE 20

READY.
 
 
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