Campbell Scientific CR6 CR6 Measurement and Control System - Page 285

String Concatenation

Page 285 highlights

Section 7. Installation Table 53. String Operators Operator Description "Subtracts" NULL ("") from the end of ASCII characters for conversion to an ASCII code (LONG data type). Example: "a" - "" = 97 ASCII codes of the first characters in each string are compared. If the difference between the codes is zero, codes for the next characters are compared. When unequal codes or NULL are encountered (NULL terminates all strings), the difference between the last compared ASCII codes is returned. Examples: Note - ASCII code for a = 97, b = 98, c = 99, d = 100, e = 101, and all strings end with NULL. Difference between NULL and NULL "abc" - "abc" = 0 Difference between e and c "abe" - "abc" = 2 Difference between c and b "ace" - "abe" = 1 Difference between d and NULL "abcd" - "abc" = 100 ASCII codes of the first characters in each string are compared. If the difference between the codes is zero, codes for the next characters are compared. When unequal codes or NULL are encountered (NULL terminates all strings), the requested comparison is made. If the comparison is true, -1 or True is returned. If false, 0 or False is returned. Examples: Expression x = "abc" = "abc" x = "abe" = "abc" x = "ace" > "abe" Result x = -1 or True x = 0 or False x = -1 or True 7.9.18.2 String Concatenation Concatenation is the building of strings from other strings ("abc123"), characters ("a" or chr()), numbers, or variables. The table String Concatenation Examples (p. 285) lists some expressions and expected results. CRBasic example Concatenation of Numbers and Strings (p. 286) demonstrates several concatenation examples. When non-string values are concatenated with strings, once a string is encountered, all subsequent operands will first be converted to a string before the + operation is performed. When working with strings, exclusive use of the & operator ensures that no string value will be converted to an integer. Table 54. String Concatenation Examples Expression Comments Str(1) = 5.4 + 3 + " Volts" Add floats, concatenate strings Str(2) = 5.4 & 3 & " Volts" Concatenate floats and strings Result "8.4 Volts" "5.43 Volts" 285

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Section 7.
Installation
Table 53.
String Operators
Operator
Description
-
"Subtracts" NULL ("") from the end of ASCII characters for conversion to
an ASCII code (LONG data type).
Example:
"a" - "" = 97
ASCII codes of the first characters in each string are compared. If the
difference between the codes is zero, codes for the next characters are
compared. When unequal codes or NULL are encountered (NULL
terminates all strings), the difference between the last compared ASCII
codes is returned.
Examples:
Note
— ASCII code for a = 97, b = 98, c = 99, d = 100, e = 101, and all
strings end with NULL.
Difference between
NULL
and
NULL
"abc" - "abc" = 0
Difference between
e
and
c
"abe" - "abc" = 2
Difference between
c
and
b
"ace" - "abe" = 1
Difference between
d
and
NULL
"abcd" - "abc" = 100
<
,
>
,
<>
,
<=
,
>=
,
=
ASCII codes of the first characters in each string are compared. If the
difference between the codes is zero, codes for the next characters are
compared. When unequal codes or NULL are encountered (NULL
terminates all strings), the requested comparison is made. If the comparison
is true, -1 or True is returned. If false, 0 or False is returned.
Examples:
Expression
Result
x = "abc" = "abc"
x = -1 or True
x = "abe" = "abc"
x = 0 or False
x = "ace" > "abe"
x = -1 or True
7.9.18.2 String Concatenation
Concatenation is the building of strings from other strings ("abc123"), characters
("a" or
chr()
), numbers, or variables.
The table
String Concatenation Examples
(p.
285)
lists some expressions and expected results.
CRBasic example
Concatenation
of Numbers and Strings
(p. 286)
demonstrates several concatenation examples.
When non-string values are concatenated with strings, once a string is
encountered, all subsequent operands will first be converted to a string before the
+ operation is performed.
When working with strings, exclusive use of the &
operator ensures that no string value will be converted to an integer.
Table 54.
String Concatenation Examples
Expression
Comments
Result
Str(1) = 5.4 + 3 + " Volts"
Add floats, concatenate strings
"8.4 Volts"
Str(2) = 5.4 & 3 & " Volts"
Concatenate floats and strings
"5.43 Volts"
285