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What do you call nested If...Then search loops?I writing some documentation and I want to describe a common code structure
which is used to step through all the items in a collection (e.g. each file in a subdirectory) while applying more and more restrictive filters so that only the desired items can fall all the way through. This method is so obvious and common it must have a name. What is it or at least, what is the best (short) way to describe it? For Each [file or whatever] In [some collection] If [test 1] Then If [test 2] Then If [test 3] Then [Found it] End If End If End If Next Ugly? :-)
I would guess it would be called "Short Circuit Evaluation via Nested If Then blocks" Thanks, Seth Rowe GY2 wrote: Show quoteHide quote > I writing some documentation and I want to describe a common code structure > which is used to step through all the items in a collection (e.g. each file > in a subdirectory) while applying more and more restrictive filters so that > only the desired items can fall all the way through. This method is so > obvious and common it must have a name. What is it or at least, what is the > best (short) way to describe it? > > For Each [file or whatever] In [some collection] > If [test 1] Then > If [test 2] Then > If [test 3] Then > [Found it] > End If > End If > End If > Next Thanks. I like the 'short circuit evaluation' languague.
And btw, it often times doesn't look ugly at all, in fact the indented structure makes it quite easy to grasp and to explain. It also doesn't run too ugly either if the successive tests are ordered correctly. In fact it can be pretty efficient because it minimizes the number of tests needed to filter down to whatever one is seeking. Show quoteHide quote "rowe_newsgroups" <rowe_em***@yahoo.com> wrote in message news:1162994593.135240.169780@h48g2000cwc.googlegroups.com... > Ugly? :-) > > I would guess it would be called "Short Circuit Evaluation via Nested > If Then blocks" > > Thanks, > > Seth Rowe > > > GY2 wrote: >> I writing some documentation and I want to describe a common code >> structure >> which is used to step through all the items in a collection (e.g. each >> file >> in a subdirectory) while applying more and more restrictive filters so >> that >> only the desired items can fall all the way through. This method is so >> obvious and common it must have a name. What is it or at least, what is >> the >> best (short) way to describe it? >> >> For Each [file or whatever] In [some collection] >> If [test 1] Then >> If [test 2] Then >> If [test 3] Then >> [Found it] >> End If >> End If >> End If >> Next > GY2 wrote:
Show quoteHide quote > I writing some documentation and I want to describe a common code structure It is usually called a (SELECT) CASE structure. For those who do not> which is used to step through all the items in a collection (e.g. each file > in a subdirectory) while applying more and more restrictive filters so that > only the desired items can fall all the way through. This method is so > obvious and common it must have a name. What is it or at least, what is the > best (short) way to describe it? > > For Each [file or whatever] In [some collection] > If [test 1] Then > If [test 2] Then > If [test 3] Then > [Found it] > End If > End If > End If > Next >This method is so obvious and common it must have a name. What is it or at least, what > is the best (short) way to describe it? use CASE, it is called "Nested-IFs", and also "Bad Programming". B. Thanks for the 'Nested-Ifs' language.
Show quoteHide quote "Brian Tkatch" <Maxwell_Sm***@ThePentagon.com> wrote in message news:1162999342.700887.39800@e3g2000cwe.googlegroups.com... > GY2 wrote: >> I writing some documentation and I want to describe a common code >> structure >> which is used to step through all the items in a collection (e.g. each >> file >> in a subdirectory) while applying more and more restrictive filters so >> that >> only the desired items can fall all the way through. This method is so >> obvious and common it must have a name. What is it or at least, what is >> the >> best (short) way to describe it? >> >> For Each [file or whatever] In [some collection] >> If [test 1] Then >> If [test 2] Then >> If [test 3] Then >> [Found it] >> End If >> End If >> End If >> Next > >>This method is so obvious and common it must have a name. What is it or >>at least, what >> is the best (short) way to describe it? > > It is usually called a (SELECT) CASE structure. For those who do not > use CASE, it is called "Nested-IFs", and also "Bad Programming". > > B. > In the interest of not confusing GY2 even more... it is never called a
(SELECT) CASE structure. :-) All the tests need to be performed to determine if [Found it] is reached. I'm not sure there is any term for this except NESTED IF's. You could write it as a compound IF statement as well. If [test 1] AndAlso [test 2] AndAlso [test 3] Then [Found it] End If What matters most is what your tests consist of. If there are one or two simple tests the compound form works fine. If there are a few more or they are a bit more complicated then the nested format works. But if the tests get "crazy" move all the comparison code into a method with a name that identifies the set of tests like IsValidCustomer() and call that method from within your For Each loop. Any overhead incurred by a method call is outweighed by the advantage of skipping over the details when reading the code and that the darn tests now have a name. Oh and (when possible) place the most restrictive (i.e. unlikely to pass) tests first. If earlier tests fail others don't have to execute. Show quoteHide quote "Brian Tkatch" <Maxwell_Sm***@ThePentagon.com> wrote in message news:1162999342.700887.39800@e3g2000cwe.googlegroups.com... > GY2 wrote: >> I writing some documentation and I want to describe a common code >> structure >> which is used to step through all the items in a collection (e.g. each >> file >> in a subdirectory) while applying more and more restrictive filters so >> that >> only the desired items can fall all the way through. This method is so >> obvious and common it must have a name. What is it or at least, what is >> the >> best (short) way to describe it? >> >> For Each [file or whatever] In [some collection] >> If [test 1] Then >> If [test 2] Then >> If [test 3] Then >> [Found it] >> End If >> End If >> End If >> Next > >>This method is so obvious and common it must have a name. What is it or >>at least, what >> is the best (short) way to describe it? > > It is usually called a (SELECT) CASE structure. For those who do not > use CASE, it is called "Nested-IFs", and also "Bad Programming". > > B. > Thanks, Tom, but actually I'm not confused at all. I've been writing code
for 35 years and understand the concepts involved and now it looks as though I may have answered my own question reasonably well in my original Subject line. I really just wondered if this type of very common, practical, and useful algorithm had a name these days. Of course you're exactly right that a Select Case structure is completely inadequate for this situation in which >ALL< tests need to be performed in order to run all the filters. And you also see that, of course, the way to make this most efficient is to start with the most restrictive tests and step into the successively less restrictive filters with each deeper nested If-Then. Show quoteHide quote "Tom Leylan" <gee@iamtiredofspam.com> wrote in message news:uMRMO90AHHA.2316@TK2MSFTNGP04.phx.gbl... > In the interest of not confusing GY2 even more... it is never called a > (SELECT) CASE structure. :-) All the tests need to be performed to > determine if [Found it] is reached. I'm not sure there is any term for > this except NESTED IF's. You could write it as a compound IF statement as > well. > > If [test 1] AndAlso [test 2] AndAlso [test 3] Then > [Found it] > End If > > What matters most is what your tests consist of. If there are one or two > simple tests the compound form works fine. If there are a few more or > they are a bit more complicated then the nested format works. But if the > tests get "crazy" move all the comparison code into a method with a name > that identifies the set of tests like IsValidCustomer() and call that > method from within your For Each loop. Any overhead incurred by a method > call is outweighed by the advantage of skipping over the details when > reading the code and that the darn tests now have a name. > > Oh and (when possible) place the most restrictive (i.e. unlikely to pass) > tests first. If earlier tests fail others don't have to execute. > > > "Brian Tkatch" <Maxwell_Sm***@ThePentagon.com> wrote in message > news:1162999342.700887.39800@e3g2000cwe.googlegroups.com... >> GY2 wrote: >>> I writing some documentation and I want to describe a common code >>> structure >>> which is used to step through all the items in a collection (e.g. each >>> file >>> in a subdirectory) while applying more and more restrictive filters so >>> that >>> only the desired items can fall all the way through. This method is so >>> obvious and common it must have a name. What is it or at least, what is >>> the >>> best (short) way to describe it? >>> >>> For Each [file or whatever] In [some collection] >>> If [test 1] Then >>> If [test 2] Then >>> If [test 3] Then >>> [Found it] >>> End If >>> End If >>> End If >>> Next >> >>>This method is so obvious and common it must have a name. What is it or >>>at least, what >>> is the best (short) way to describe it? >> >> It is usually called a (SELECT) CASE structure. For those who do not >> use CASE, it is called "Nested-IFs", and also "Bad Programming". >> >> B. >> > > The other two posters who replied are being hyper-critical. There is a place
for nested if's. And, contrary to what one of them said, 'Select Case' is not a general purpose replacement for nested if's. -- Show quoteHide quoteDavid Anton www.tangiblesoftwaresolutions.com Instant C#: VB to C# converter Instant VB: C# to VB converter Instant C++: C#/VB to C++ converter Instant Python: VB to Python converter "GY2" wrote: > I writing some documentation and I want to describe a common code structure > which is used to step through all the items in a collection (e.g. each file > in a subdirectory) while applying more and more restrictive filters so that > only the desired items can fall all the way through. This method is so > obvious and common it must have a name. What is it or at least, what is the > best (short) way to describe it? > > For Each [file or whatever] In [some collection] > If [test 1] Then > If [test 2] Then > If [test 3] Then > [Found it] > End If > End If > End If > Next > > > > Thanks for the support, David. Yes, obviously Case statments would not work
for the multi-layered filtering I'm trying to document, but not receiving perfect replies is no reason not to ask the question. It's good to be able to receive something sent with a sense of humor in the same way. I thought the one word reply--Ugly--was pretty funny. Show quoteHide quote "David Anton" <DavidAn***@discussions.microsoft.com> wrote in message news:904B22ED-2624-4A6E-BB42-B421623C15D4@microsoft.com... > The other two posters who replied are being hyper-critical. There is a > place > for nested if's. And, contrary to what one of them said, 'Select Case' is > not a general purpose replacement for nested if's. > -- > David Anton > www.tangiblesoftwaresolutions.com > Instant C#: VB to C# converter > Instant VB: C# to VB converter > Instant C++: C#/VB to C++ converter > Instant Python: VB to Python converter > > > "GY2" wrote: > >> I writing some documentation and I want to describe a common code >> structure >> which is used to step through all the items in a collection (e.g. each >> file >> in a subdirectory) while applying more and more restrictive filters so >> that >> only the desired items can fall all the way through. This method is so >> obvious and common it must have a name. What is it or at least, what is >> the >> best (short) way to describe it? >> >> For Each [file or whatever] In [some collection] >> If [test 1] Then >> If [test 2] Then >> If [test 3] Then >> [Found it] >> End If >> End If >> End If >> Next >> >> >> >> David Anton wrote:
> The other two posters who replied are being hyper-critical. Actually, i answered the question. I also added a comment, because itcannot be stressed enough. In most cases of nested-ifs, a CASE statement should be used. > There is a place for nested if's. It is rare. Besides, there are limits on how nested an IF can be. And,it is *very* hard to follow in real code. > And, contrary to what one of them said, 'Select Case' is not a general purpose replacement for nested if's. Yes it is. It also makes the code more clear. It is a rare case whereCASE cannot be used. --- It could be that i'm so senstivie about this right now becaise i'm fixing someone's code who indeed used nested IFs where CASE would clearly be the choice. And since there are no comments, it makes understanding the code twice as hard. B. We'll have to agree to disagree then. I find 'Select Case' more appropriate
where you care about many possible values of an expression. -- Show quoteHide quoteDavid Anton www.tangiblesoftwaresolutions.com Instant C#: VB to C# converter Instant VB: C# to VB converter Instant C++: C#/VB to C++ converter Instant Python: VB to Python converter "Brian Tkatch" wrote: > David Anton wrote: > > The other two posters who replied are being hyper-critical. > > Actually, i answered the question. I also added a comment, because it > cannot be stressed enough. In most cases of nested-ifs, a CASE > statement should be used. > > > There is a place for nested if's. > > It is rare. Besides, there are limits on how nested an IF can be. And, > it is *very* hard to follow in real code. > > > And, contrary to what one of them said, 'Select Case' is not a general purpose replacement for nested if's. > > Yes it is. It also makes the code more clear. It is a rare case where > CASE cannot be used. > > --- > > It could be that i'm so senstivie about this right now becaise i'm > fixing someone's code who indeed used nested IFs where CASE would > clearly be the choice. And since there are no comments, it makes > understanding the code twice as hard. > > B. > > David Anton wrote:
> We'll have to agree to disagree then. I find 'Select Case' more appropriate Yes, which is the case in the OPs given example.> where you care about many possible values of an expression. B. Please re-read the original post. The OP example shows 3 independent tests,
not 3 possible values of an expression. -- Show quoteHide quoteDavid Anton www.tangiblesoftwaresolutions.com Instant C#: VB to C# converter Instant VB: C# to VB converter Instant C++: C#/VB to C++ converter Instant Python: VB to Python converter "Brian Tkatch" wrote: > > David Anton wrote: > > We'll have to agree to disagree then. I find 'Select Case' more appropriate > > where you care about many possible values of an expression. > > Yes, which is the case in the OPs given example. > > B. > > Exactly.
Show quoteHide quote "David Anton" <DavidAn***@discussions.microsoft.com> wrote in message news:CB5814BF-A2A5-4DE1-8650-7708590E9B4A@microsoft.com... > Please re-read the original post. The OP example shows 3 independent > tests, > not 3 possible values of an expression. > -- > David Anton > www.tangiblesoftwaresolutions.com > Instant C#: VB to C# converter > Instant VB: C# to VB converter > Instant C++: C#/VB to C++ converter > Instant Python: VB to Python converter > > > "Brian Tkatch" wrote: > >> >> David Anton wrote: >> > We'll have to agree to disagree then. I find 'Select Case' more >> > appropriate >> > where you care about many possible values of an expression. >> >> Yes, which is the case in the OPs given example. >> >> B. >> >> David Anton wrote:
Show quoteHide quote > Please re-read the original post. The OP example shows 3 independent tests, I did re-read it before i replied:> not 3 possible values of an expression. > -- > David Anton > www.tangiblesoftwaresolutions.com > Instant C#: VB to C# converter > Instant VB: C# to VB converter > Instant C++: C#/VB to C++ converter > Instant Python: VB to Python converter > > > "Brian Tkatch" wrote: > > > > > David Anton wrote: > > > We'll have to agree to disagree then. I find 'Select Case' more appropriate > > > where you care about many possible values of an expression. > > > > Yes, which is the case in the OPs given example. > > > > B. > > > > For Each [file or whatever] In [some collection] If [test 1] Then If [test 2] Then If [test 3] Then [Found it] End If End If End If Next In this case there's only one "Found it". The assumption is that the elses will feed the other cases. And that is perfect for a CASE statement. B. Again, I think you're assuming that the if then structure will only
test one variable. In this case you could rewrite it using a Select Case statement. But with multiple variables if thens are clearly better suited for this. Take the following adaptation of the OP's structure: dim a, b, c as integer a = 5 b = 7 c = 7 if a > 4 then if b > 6 then if c > 6 then msgbox("found it") end if end if end if How exactly would you rewrite this with a select case? Thanks, Seth Rowe Brian Tkatch wrote: Show quoteHide quote > David Anton wrote: > > Please re-read the original post. The OP example shows 3 independent tests, > > not 3 possible values of an expression. > > -- > > David Anton > > www.tangiblesoftwaresolutions.com > > Instant C#: VB to C# converter > > Instant VB: C# to VB converter > > Instant C++: C#/VB to C++ converter > > Instant Python: VB to Python converter > > > > > > "Brian Tkatch" wrote: > > > > > > > > David Anton wrote: > > > > We'll have to agree to disagree then. I find 'Select Case' more appropriate > > > > where you care about many possible values of an expression. > > > > > > Yes, which is the case in the OPs given example. > > > > > > B. > > > > > > > > > I did re-read it before i replied: > > For Each [file or whatever] In [some collection] > If [test 1] Then > If [test 2] Then > If [test 3] Then > [Found it] > End If > End If > End If > Next > > In this case there's only one "Found it". The assumption is that the > elses will feed the other cases. And that is perfect for a CASE > statement. > > B. rowe_newsgroups wrote:
Show quoteHide quote > Again, I think you're assuming that the if then structure will only Yes, i was assuming one variable. That is the usual case.> test one variable. In this case you could rewrite it using a Select > Case statement. But with multiple variables if thens are clearly better > suited for this. Take the following adaptation of the OP's structure: > > dim a, b, c as integer > > a = 5 > b = 7 > c = 7 > > if a > 4 then > if b > 6 then > if c > 6 then > msgbox("found it") > end if > end if > end if > > How exactly would you rewrite this with a select case? > > Thanks, > > Seth Rowe > > > Brian Tkatch wrote: > > David Anton wrote: > > > Please re-read the original post. The OP example shows 3 independent tests, > > > not 3 possible values of an expression. > > > -- > > > David Anton > > > www.tangiblesoftwaresolutions.com > > > Instant C#: VB to C# converter > > > Instant VB: C# to VB converter > > > Instant C++: C#/VB to C++ converter > > > Instant Python: VB to Python converter > > > > > > > > > "Brian Tkatch" wrote: > > > > > > > > > > > David Anton wrote: > > > > > We'll have to agree to disagree then. I find 'Select Case' more appropriate > > > > > where you care about many possible values of an expression. > > > > > > > > Yes, which is the case in the OPs given example. > > > > > > > > B. > > > > > > > > > > > > > > I did re-read it before i replied: > > > > For Each [file or whatever] In [some collection] > > If [test 1] Then > > If [test 2] Then > > If [test 3] Then > > [Found it] > > End If > > End If > > End If > > Next > > > > In this case there's only one "Found it". The assumption is that the > > elses will feed the other cases. And that is perfect for a CASE > > statement. > > > > B. > Again, I think you're assuming that the if then structure will only > test one variable. In this case you could rewrite it using a Select B. > The other two posters who replied are being hyper-critical. Hey be nice! (joking) I did answer the post and put why nested if's areimportant (short circuit evaluation). The reason I put "Ugly" was more to emphasize how nested if's can easily become giant scary beasts if used incorrectely. In it's pure form (like in the example) this structure is very easy to read and maintain. A lot of times programmers (new ones especially) will add way to much stuff to the if then tests - like multiple exit points, etc. - and cause the structure to become confusing and unmaintainable. I'm sure with your experience you know what I'm talking about :-) Now-a-days you could even replace the pure if-then structures with just AndAlso statements if you wanted to. Am I making more sense now? Thanks, Seth Rowe David Anton wrote: Show quoteHide quote > The other two posters who replied are being hyper-critical. There is a place > for nested if's. And, contrary to what one of them said, 'Select Case' is > not a general purpose replacement for nested if's. > -- > David Anton > www.tangiblesoftwaresolutions.com > Instant C#: VB to C# converter > Instant VB: C# to VB converter > Instant C++: C#/VB to C++ converter > Instant Python: VB to Python converter > > > "GY2" wrote: > > > I writing some documentation and I want to describe a common code structure > > which is used to step through all the items in a collection (e.g. each file > > in a subdirectory) while applying more and more restrictive filters so that > > only the desired items can fall all the way through. This method is so > > obvious and common it must have a name. What is it or at least, what is the > > best (short) way to describe it? > > > > For Each [file or whatever] In [some collection] > > If [test 1] Then > > If [test 2] Then > > If [test 3] Then > > [Found it] > > End If > > End If > > End If > > Next > > > > > > > > Sure you're making sense now, as you have all along--it's all good. I'm
working with old VB 6 code that's already a done deal. All I wanted to know was what the hell to call those kinds of structures. Show quoteHide quote "rowe_newsgroups" <rowe_em***@yahoo.com> wrote in message news:1163005393.909022.147040@e3g2000cwe.googlegroups.com... >> The other two posters who replied are being hyper-critical. > > Hey be nice! (joking) I did answer the post and put why nested if's are > important (short circuit evaluation). > > The reason I put "Ugly" was more to emphasize how nested if's can > easily become giant scary beasts if used incorrectely. In it's pure > form (like in the example) this structure is very easy to read and > maintain. A lot of times programmers (new ones especially) will add way > to much stuff to the if then tests - like multiple exit points, etc. - > and cause the structure to become confusing and unmaintainable. I'm > sure with your experience you know what I'm talking about :-) > Now-a-days you could even replace the pure if-then structures with just > AndAlso statements if you wanted to. > > Am I making more sense now? > > Thanks, > > Seth Rowe > > > David Anton wrote: >> The other two posters who replied are being hyper-critical. There is a >> place >> for nested if's. And, contrary to what one of them said, 'Select Case' >> is >> not a general purpose replacement for nested if's. >> -- >> David Anton >> www.tangiblesoftwaresolutions.com >> Instant C#: VB to C# converter >> Instant VB: C# to VB converter >> Instant C++: C#/VB to C++ converter >> Instant Python: VB to Python converter >> >> >> "GY2" wrote: >> >> > I writing some documentation and I want to describe a common code >> > structure >> > which is used to step through all the items in a collection (e.g. each >> > file >> > in a subdirectory) while applying more and more restrictive filters so >> > that >> > only the desired items can fall all the way through. This method is so >> > obvious and common it must have a name. What is it or at least, what is >> > the >> > best (short) way to describe it? >> > >> > For Each [file or whatever] In [some collection] >> > If [test 1] Then >> > If [test 2] Then >> > If [test 3] Then >> > [Found it] >> > End If >> > End If >> > End If >> > Next >> > >> > >> > >> > > GY2,
I always call it a nested If's inside a loop. As simple as you wrote it. By the way about the comments, I assume that this is the most simple sample. In any case nobody would use it like your sample of course. You see that this is very well documentative when you see how ugly this is mosly in all from C derived languages. Cor Show quoteHide quote "GY2" <2muchspam@wherever.com> schreef in bericht news:%23klOPzzAHHA.4592@TK2MSFTNGP03.phx.gbl... >I writing some documentation and I want to describe a common code structure >which is used to step through all the items in a collection (e.g. each file >in a subdirectory) while applying more and more restrictive filters so that >only the desired items can fall all the way through. This method is so >obvious and common it must have a name. What is it or at least, what is the >best (short) way to describe it? > > For Each [file or whatever] In [some collection] > If [test 1] Then > If [test 2] Then > If [test 3] Then > [Found it] > End If > End If > End If > Next > > > Thanks Cor. Yes, the format in VB can be pretty nice if you're into
'literate programming'. Show quoteHide quote "Cor Ligthert [MVP]" <notmyfirstn***@planet.nl> wrote in message news:udTeP81AHHA.4292@TK2MSFTNGP02.phx.gbl... > GY2, > > I always call it a nested If's inside a loop. As simple as you wrote it. > > By the way about the comments, I assume that this is the most simple > sample. > In any case nobody would use it like your sample of course. > > You see that this is very well documentative when you see how ugly this is > mosly in all from C derived languages. > > Cor > > "GY2" <2muchspam@wherever.com> schreef in bericht > news:%23klOPzzAHHA.4592@TK2MSFTNGP03.phx.gbl... >>I writing some documentation and I want to describe a common code >>structure which is used to step through all the items in a collection >>(e.g. each file in a subdirectory) while applying more and more >>restrictive filters so that only the desired items can fall all the way >>through. This method is so obvious and common it must have a name. What is >>it or at least, what is the best (short) way to describe it? >> >> For Each [file or whatever] In [some collection] >> If [test 1] Then >> If [test 2] Then >> If [test 3] Then >> [Found it] >> End If >> End If >> End If >> Next >> >> >> > > Just to add another voice to the cacophony,
sometimes you just HAVE to use nested Ifs. But with VB2005, you can also use the new OrElse and put all of those together. Like C#'s usage of Else, it will stop evaluating options when it hits a false one. For Each [file or whatever] In [some collection] If [test 1] _ OrElse [test 2] _ OrElse [test 3] Then [Found it] End If Next Of course, this assumes you don't care which test it passed. Robin S. Show quoteHide quote "GY2" <2muchspam@wherever.com> wrote in message news:%23klOPzzAHHA.4592@TK2MSFTNGP03.phx.gbl... >I writing some documentation and I want to describe a common code structure >which is used to step through all the items in a collection (e.g. each file >in a subdirectory) while applying more and more restrictive filters so that >only the desired items can fall all the way through. This method is so >obvious and common it must have a name. What is it or at least, what is the >best (short) way to describe it? > > For Each [file or whatever] In [some collection] > If [test 1] Then > If [test 2] Then > If [test 3] Then > [Found it] > End If > End If > End If > Next > > > RobinS wrote:
> Just to add another voice to the cacophony, Yes, sometimes. Most cases not.> sometimes you just HAVE to use nested Ifs. B. For what you have shown, I would suggest "andalso", i.e.,
if test1 andalso test2 andalso test3 then end if -- Show quoteHide quoteDennis in Houston "GY2" wrote: > I writing some documentation and I want to describe a common code structure > which is used to step through all the items in a collection (e.g. each file > in a subdirectory) while applying more and more restrictive filters so that > only the desired items can fall all the way through. This method is so > obvious and common it must have a name. What is it or at least, what is the > best (short) way to describe it? > > For Each [file or whatever] In [some collection] > If [test 1] Then > If [test 2] Then > If [test 3] Then > [Found it] > End If > End If > End If > Next > > > > Well, the code has already been written in VB 6 years ago. All I'm trying do
to is document it and find out what the name of this kind of structure is. Thanks, though. It's an interesting discussion. Show quoteHide quote "Dennis" <Den***@discussions.microsoft.com> wrote in message news:CE5CB189-C53D-4DF1-A9B7-B7B4D5A4B6AF@microsoft.com... > For what you have shown, I would suggest "andalso", i.e., > > if test1 andalso test2 andalso test3 then > > end if > > -- > Dennis in Houston > > > "GY2" wrote: > >> I writing some documentation and I want to describe a common code >> structure >> which is used to step through all the items in a collection (e.g. each >> file >> in a subdirectory) while applying more and more restrictive filters so >> that >> only the desired items can fall all the way through. This method is so >> obvious and common it must have a name. What is it or at least, what is >> the >> best (short) way to describe it? >> >> For Each [file or whatever] In [some collection] >> If [test 1] Then >> If [test 2] Then >> If [test 3] Then >> [Found it] >> End If >> End If >> End If >> Next >> >> >> >> If you are using VB 2005, you could rewrite this as
For Each [file or whatever] In [some collection] if not [test 1] then Continue For if not [test 2] then Continue For ... [Found it] Next This has the benefit of eliminating the confusion that results when adding an additional test. If you don't have VB 2005, I would rewrite as For Each [file or whatever] In [some collection] if passesfilters(file) then [Found it] Next Private function PassesFilters(file as object) as boolean if not [test 1] then return false if not [test 2] then return false if not [test 3] then return false return true end function Again, this eliminates the issue of screwing up the nesting when you change the number or nature of the tests. Mike. Show quoteHide quote "GY2" <2muchspam@wherever.com> wrote in message news:%23klOPzzAHHA.4592@TK2MSFTNGP03.phx.gbl... > I writing some documentation and I want to describe a common code structure > which is used to step through all the items in a collection (e.g. each file > in a subdirectory) while applying more and more restrictive filters so that > only the desired items can fall all the way through. This method is so > obvious and common it must have a name. What is it or at least, what is the > best (short) way to describe it? > > For Each [file or whatever] In [some collection] > If [test 1] Then > If [test 2] Then > If [test 3] Then > [Found it] > End If > End If > End If > Next > > > |
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