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[REBOL] Re: Confusion about foreach

From: rebolek::gmail at: 17-Mar-2006 17:00

Hi Steve, Robert is right, string consists of single characters. Look at this console session:
>> record: "abcd"
== "abcd"
>> record/1
== #"a"
>> type? record/1
== char! So, in your code change this line: if TEST-RECORD/1 = "4" [ to if TEST-RECORD/1 = #"4" [ and it should work. By, Rebolek On 3/17/06, Robert Brandner <robert_brandner-gmx.at> wrote:
> > Hi Steve, > > I think you have to write #"4" instead of "4" as a string consists of > single > characters. > > regards, > Robert > > Steven White wrote: > > There must be some simple little thing I don't understand about foreach, > > or about conditions, and I am wondering if someone can explain. I have > > isolated the problem into a test script at the end of this message. > > > > The thing I am trying to program is: > > > > I have a text file containing several types of fixed-format records. > > It is for transferring money to the bank. A type of record is > > identified by a single digit in the first character position of the > > record. In the file, there is one particular record I want to find, > > the only one with a particular record type code in the first position (a > > trailer record, but not the last record in the file, so I can't just use > > "last.") > > > > So, I read the file into memory with read/lines. Each line becomes a > > string. I loop through the block of strings (lines) and check the first > > character of each. When I find the record type (first character) I am > > looking for, I save that record in another place so I can examine it > > more detail later in the program. > > > > In the following test script, if you run it, you see that "print > > TEST-RECORD/1" is executed and displays the first character of every > > record. BUT, HOLD-TEST-RECORD never gets set to anything (besides its > > initial value of a null string) and "print 'We found record type 4'" > > never is executed. So that condition of 'if TEST-RECORD/1 = "4"' is > > never true. > > > > What am I doing wrong? It looks so obviously correct. I read the > > manual, and I am "sure" I have seen code like that before. > > > > Thank you. > > > > ;;;; test script > > REBOL [ > > ] > > > > TEST-FILE: [ > > "1this is record one" > > "2this is record two" > > "3this is one of many type 3 records" > > "3this is one of many type 3 records" > > "4this is the record we want" > > "9this is some ending record" > > ] > > > > HOLD-FOUND-RECORD: copy "" > > > > foreach TEST-RECORD TEST-FILE [ > > print TEST-RECORD/1 > > if TEST-RECORD/1 = "4" [ > > HOLD-FOUND-RECORD: copy TEST-RECORD > > print "We found record type 4" > > ] > > ] > > > > print rejoin ["HOLD-FOUND-RECORD=" HOLD-FOUND-RECORD] > > > > ;;;; end of test script > > > > > > Steven White > > City of Bloomington > > 1800 W Old Shakopee Rd > > Bloomington MN 55431-3096 > > USA > > 952-563-4882 (voice) > > 952-563-4672 (fax) > > steven.white-ci.bloomington.mn.us > > -- > To unsubscribe from the list, just send an email to > lists at rebol.com with unsubscribe as the subject. >
-- / Boleslav Brezovsky http://krutek.info \