From the start, FoxPro has always had a wide range of commands and functions for
processing text - more than are strictly necessary for a database
language. This is a list of some of the more useful commands and
functions in Visual FoxPro. Many of them can accept extra optional parameters. Look
in the FoxPro Help system for more information.
The distinction between commands and functions is that commands
do something whereas functions just return a value to be displayed
or used in another command.
FoxPro syntax requires that functions are always followed by a pair of brackets to hold
the parameters - even if there's no parameter required. Unlike Visual
Basic, FoxPro does not use the "$" suffix in functions to
force them to return a string. VFP variables are all of the same type,
something equivalent to a variant in VB.
| <text1> + <text2> |
return <text1text2> |
| <text1> - <text2> |
return <text1text2> with any spaces from <text1>
removed and added to the end of the result. An unusual function
but sometimes useful.
|
| <text1> $ <text2> |
return .T. if <text1> exists in <text2>
|
| ALLTRIM(<text>) |
return <text> with all leading and trailing spaces removed. In
VFP 9 this function can remove characters other than spaces by specifying an extra parameter.
|
| AT(<char>,<text>) |
return the position of character <char> in string
<text> or 0 if <char> is not found. The RAT()
function does the same but starting at the end of the
target string <text>.
|
| ATC(<char>,<text>) |
this is identical to to the AT() function but it is not case-sensitive. |
| CTOD(<text>) |
return <text> as a variable in date format. Note that the CTOD function
will fail if STRICTDATE is set to 2.
|
| DTOC(<date>) |
return <date> as a string in 'dd/mm/yy' or
'dd/mm/yyyy' format depending on the state of SET CENTURY and
SET DATE.
|
| DTOS(<date>) |
return <date> as a variable of type string in 'yyyymmdd' format.
Use the DTOS function when you are wanting to index on an expression like
Surname + DTOS(DateOfBirth).
|
| FILETOSTR(<filename>) |
return a string holding the contents of the file named
<filename>. Useful in combination with
STRTOFILE
because you can read a file from disk into memory, process it very quickly, and then write
it back out to disk. The only limitation in the 16Mb limit on FoxPro
string variables.
|
| ISALPHA(<text>) |
return .T. if the first character of <text> is alphabetic. |
| ISLOWER(<text>) |
return .T. if the first character of <text> is lower case. |
| ISUPPER(<text>) |
return .T. if the first character of <text> is upper case. |
| LEFT(<text>, <n>) |
return the leftmost <n> characters of <text>.
Note that this will include any spaces. |
| LEN(<text>) |
return the length of <text> - including spaces. Remember this
when you are getting the length of data retrieved from a field.
|
| LIKE(<text1>, <text2>) |
compares <text1> and <text2> character by character and
returns .T. if they match. <text1> can include the wild
cards '*' and '?'.
|
| LOWER(<text>) |
return <text> as text in lowercase. |
| LTRIM(<text>) |
return <text> with the leading spaces removed. |
| OCCURS(<text1>, <text2>) |
return the number of times that the <text1> occurs in <text2>.
|
| PADC(<text>, <n>, <char>) |
pad <text> to <n> characters long by adding equal numbers of <char> to
both ends.
|
| PADL(<text>, <n>, <char>) |
pad <text> to <n> characters long by adding <char> to the start.
|
| PADR(<text>, <n>, <char>) |
pad <text> to <n> characters long by adding <char> to the end.
|
| PROPER(<text>) |
return <text> in lowercase text with the initial letters
capitalised. Not as useful as you might think because many
proper names include a mixture of uppercase and lowercase
letters which must be retained - "McDonald" and "IBM" for example.
|
| RIGHT(<text>, <n>) |
return the rightmost <n> characters of <text>.
Remember that the count of <n> will include trailing spaces.
|
| RTRIM(<text>) |
return <text> with the trailing spaces removed. |
| STR(<number>,<m>,<n>) |
return <number> as a string of <m> characters rounded to <n> decimals.
|
| STREXTRACT(<text>, <begin>, <end>) |
returns the characters between the delimiters <begin> and
<end> inside <text>. Additional parameters let you
distinguish between multiple occurences of the delimiters and
choose whether the delimiters are included in the text which is to be
returned. The StrExtract function is very useful when processing HTML and XML.
|
|
STRTOFILE(<filename>)
|
write a string to a file and return the number of bytes written.
Useful in combination with
FILETOSTR
because you can read a file from disk into memory, process it,
and write it back out to disk.
|
| STRTRAN(<text>, <a>, <b>) |
replace every occurrence of <a> inside <text> with
another character or characters <b>.
|
| STUFF(<text>, <m>, <n>, <a>) |
replace <n> characters from position <m> in
<text> with the character or characters <a>.
|
| TRIM(<text>) |
identical to RTRIM. |
| SUBSTR(<text>,<m>,<n>) |
return <n> characters from within <text> starting
at character <m>.
|
| UPPER(<text>) |
return <text> in upper case text. |
