Parallax BASIC Stamp 1, Programming Manual

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5: BASIC Stamp Command Reference – LOOKDOWN
BASIC Stamp Programming Manual 2.0c
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Page 177
LOOKDOWN
BS1 BS2 BS2e BS2sx BS2p
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 the BS2, BS2e, BS2sx and BS2p, 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 5.36) 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
BS1, BS2, BS2e, BS2sx and BS2p
Limit of value
entries
256
Starting index
number
0
If value list
contains no
match…
Variable is left unaffected
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:
1
2
e
2
sx
2
p
2
1
NOTE: Expressions are not
allowed as arguments on the BS1.
Table 5.35: LOOKDOWN Quick
Facts.
2
e
2
sx
2
p
2