Jane.doe at 11:20, 10 January 2020

2020-01-10T11:20:04Z

@@ Line 73: / Line 73: @@
 * formatting a string with [[F$FAO()]]
 * wilcard matching with [[F$MATCH_WILD()]]
 =Strings vs Integers=

Jane.doe: Created page with "A '''string''' is a data type in OpenVMS that represents a sequence of ASCII characters. Here is a symbol that has a string type: $ TEST == "This is a st..."

2019-11-28T12:02:33Z

Created page with "A '''string''' is a data type in OpenVMS that represents a sequence of ASCII characters. Here is a symbol that has a string type: <nowiki> $ TEST == "This is a st..."

New page

A '''string''' is a data type in OpenVMS that represents a sequence of ASCII characters. Here is a [[Symbol|symbol]] that has a string type:

<nowiki>
$ TEST == "This is a string symbol"
$ SHOW SYMBOL TEST
TEST == "This is a string symbol"
</nowiki>

To label a sequence of characters as a string, put it in double quotes.

=String Operations=
The following string operations are possible:
* string concatenation:
<nowiki>
$ a = "This is a "
$ b = "string"
$ c = a + b
$ show sym c
C = "This is a string"
</nowiki>
* string subtraction (works for the first substring located inside of the string):
<nowiki>
3$ d = c-"a"
SMAN43$ show sym d
D = "This is string"
</nowiki>
* locating substrings in a string (with [[F$LOCATE()]]):
<nowiki>
$ WRITE SYS$OUTPUT F$LOCATE("E","HELLO")
1
</nowiki>
* obtaining string length (with [[F$LENGTH()]]):
<nowiki>
$ WRITE SYS$OUTPUT F$LENGTH("HELLO")
5
</nowiki>
* extracting a substring from a string (with [[F$EXTRACT()]]):
<nowiki>
$ WRITE SYS$OUTPUT F$EXTRACT("1",2,"HELLO")
EL
</nowiki>
* extracting an element from a string with delimiters (with [[F$ELEMENT()]]):
<nowiki>
$ WRITE SYS$OUTPUT F$ELEMENT(0,"/","1/2/3")
1
</nowiki>
* changing string case with [[F$EDIT()]]:
<nowiki>
$ a = "HeLlO"
$ write sys$output f$edit(a,"UPCASE")
HELLO
$ write sys$output f$edit(a,"LOWERCASE")
hello
</nowiki>
* removing double spaces from a string:
<nowiki>
SMAN43$ a = " hello there"
SMAN43$ write sys$output f$edit(a,"compress")
hello there
</nowiki>
* removing all spaces from a string:
<nowiki>
SMAN43$ a = " hello there"
SMAN43$ write sys$output f$edit(a,"collapse")
hellothere
</nowiki>
* removing [[Comment|comments]] from a string:
<nowiki>
$ a = "Hello! How can I help?"
$ write sys$output f$edit(a,"uncomment")
Hello
</nowiki>
* formatting a string with [[F$FAO()]]
* wilcard matching with [[F$MATCH_WILD()]]

=Strings vs Integers=
You can convert an [[Integer|integer]] into a string with [[F$STRING()]]. To convert a string into an integer, use [[F$INTEGER()]]. If the string being converted to an integer consists of numbers, it will be converted to that number:
<nowiki>
SMAN43$ a = "12"
SMAN43$ b = f$integer(a)
SMAN43$ show sym b
B = 12 Hex = 0000000C Octal = 00000000014
</nowiki>

If it contains alphanumeric characters, the evaluation of the Boolean value is used: all strings beginning with "Y" or "y" are evaluated as 1 and all other strings as 0:
<nowiki>
SMAN43$ a = "a12"
SMAN43$ b = f$integer(a)
SMAN43$ show sym b
B = 0 Hex = 00000000 Octal = 00000000000
</nowiki>

=String Symbols=
To define a string [[Symbol|symbol]], you can use either a colon (:) before the equals sign or the double quotes (") around the equivalence string. The difference is that the quotes preserve the case of the string and the colon does not:
<nowiki>
SMAN43$ a := Hello
SMAN43$ show sym a
A = "HELLO"
SMAN43$ a = "Hello"
SMAN43$ show sym a
A = "Hello"
</nowiki>

=Literal Quotes=
To put double quotes inside of a string, use two sets of double quotes:
<nowiki>
$ a = "Here are some ""quotes"" for you"
$ show sym a
A = "Here are some "quotes" for you"
</nowiki>
A single double quote (") symbol can be defined like this:
<nowiki>
$ a = """"
$ show sym a
A = """
</nowiki>
To put single quotes inside of a string, define a symbol for a single quote and then concatenate that with the other strings:
<nowiki>
$ a = "'"
$ show sym a
A = "'"
$ b = "Here are some "+a+"single quotes"+a+" for you"
$ show sym b
B = "Here are some 'single quotes' for you"
</nowiki>
The reason you cannot just put single quotes inside of a string is that they are used to [[Symbol#Forcing Symbol Substitution|force symbol substitution]] inside of a string.

String - Revision history

Jane.doe at 11:20, 10 January 2020

Jane.doe: Created page with "A '''string''' is a data type in OpenVMS that represents a sequence of ASCII characters. Here is a symbol that has a string type: $ TEST == "This is a st..."