BASIC stamp manual v2.2

5: BASIC Stamp Command Reference – LOOKDOWN
BASIC Stamp Syntax and Reference Manual 2.2 • www.parallax.com • Page 271
LOOKDOWN
BS1 BS2 BS2e BS2sx BS2p BS2pe BS2px
LOOKDOWN Target, ( Value0, Value1, ...ValueN ), Variable
LOOKDOWN Target, { ComparisonOp } [ Value0, Value1, ...ValueN ], Variable
Function
Compare Target value to a list of values and store the index number of the
first value that matches into Variable. If no value in the list matches,
Variable is left unaffected. On all BS2 models, the optional ComparisonOp is
used as criteria for the match; the default criteria is "equal to."
• Target is a variable/constant/expression (0 – 65535) to be compared
to the values in the list.
• ComparisonOp is an optional comparison operator (as described in
Table 5.53) to be used as the criteria when comparing values. When
no ComparisonOp is specified, equal to (=) is assumed. This
argument is not available on the BS1.
• Values are variables/constants/expressions (0 – 65535) to be
compared to Target.
• Variable is a variable (usually a byte) that will be set to the index (0 –
255) of the matching value in the Values list. If no matching value is
found, Variable is left unaffected.
Quick Facts
Table 5.52: LOOKDOWN Quick
Facts.
BS1 and all BS2 Models
Limit of Value
Entries
256
Starting Index
Number
0
If value list
contains no
match…
Variable is left unaffected
Related
Command
LOOKUP
Explanation
LOOKDOWN works like the index in a book. In an index, you search for a
topic and get the page number. LOOKDOWN searches for a target value
in a list, and stores the index number of the first match in a variable. For
example:
NOTE: Expressions are not allowed as
arguments on the BS1.
1
All 2
1
All 2