- tagAny Type
An arbitrary named placeholder used in the expression/command specified by Each to refer to each entry in List. Any type
- eachAny Type
An expression or command that you want to execute on each entry in List. Any type
A CR-LF delimited list of entries on which you want to operate, or an array. Character
A filter expression that returns a .t. or .f. value.
Executes the command specified by "each" on every entry in a CR-LF delimited "list". "Tag" refers to each entry in the "list".
*FOR_EACH() is a very quick and efficient way of performing a command on every entry in a CR-LF delimited list of values, or in an array. It is an alternative to writing an Xbasic loop.
Result is a CR-LF delimited list of return values generated when the command/expression specified by Each is executed.
The *COUNTER() function can be used inside the *FOR_EACH() function to return the current count of the number of entries processed. See example below.
It is easiest to explain how this function works by example. Assume you have a CR-LF list of names:
Names = <<%str% Smith,John Jones,Jenny Kelly,Kim %str%
You would like to get a list of first names only by selecting the word after the comma:
First_names = *for_each(fullname, word(fullname, 2, ","),names) ? First_names = John Jenny Kim
In this example, " fullname" is an arbitrary tag that is defined. The Each argument is: word(fullname, 2, ","). This function is performed on each entry in the input list of names. The tag fullname is used in the expression to refer to each entry in the input list.
If the tag had been specified as "foo" for example, then the expression would be:
First_names = *for_each(foo, word(foo, 2, ","),names) ? First_names = John Jenny Kim
In this case, this same result can be achieved using the word_change() function:
First_names = word_change("$(,)+1", names, crlf() ) ? First_names = John Jenny Kim
However, the syntax for *FOR_EACH() is easier to understand since it uses standard Alpha Anywhere functions.
In other situations, such as the example below, where the *FOR_EACH() function is executing a command, WORD_CHANGE() cannot be used as an alternative.
To delete all of the files with a .tmp extension in a folder.
file_list = filefind.get("c:\temp_FILEs\*.tmp", 0, "PN") *for_each(filename, file.remove(filename), file_list)
Using counter() to create a numbered list.
dim list as c = <<%str% apples oranges pears %str% ? *for_each(item, *counter() + ") "+item, list) = 1) apples 2) oranges 3) pears
Using an array as in the input to the function.
dim a as P a.fname = "fred" a.lname = "smith" a.city = "new york" a.fname = "kelly" a.lname = "jones" a.city = "chicago" a.fname = "aaron" a.lname = "brown" a.city = "london" ? *for_each(x,x.fname + " " + x.lname,a) = fred smith kelly jones aaron brown
This example demonstrates using a filter expression. Only the entries where the filter expression returns true are returned:
dim txt as c=<<%str% Smith,Jenny Jones,Michelle Amira,Stone Krayzelberg,Lawson %str% ? *for_each(x,word(x,1,","),txt,x>"K") = Smith Krayzelberg
In the following example, we read data from the customer table into a property array, and then use *FOR_EACH() to dump out values from the array into a CR-LF string.
dim PropArray 100 as P PropArray.initialize_from_table("customer") ? *for_each(x,x.firstname +" " + x.lastname + " lives in " + x.bill_city + ", " + x.bill_state_region,PropArray) = Michael Graham lives in Natick, MA Aaron Peabody lives in Brockton, MA Janet Rebo lives in Keene, NH David Mesner lives in York Beach, ME Evan Feld lives in Acra, NY