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  • Dynamically evaluating simple boolean logic in Python

    - by a paid nerd
    I've got some dynamically-generated boolean logic expressions, like: (A or B) and (C or D) A or (A and B) A empty - evaluates to True The placeholders get replaced with booleans. Should I, Convert this information to a Python expression like True or (True or False) and eval it? Create a binary tree where a node is either a bool or Conjunction/Disjunction object and recursively evaluate it? Convert it into nested S-expressions and use a Lisp parser? Something else? Suggestions welcome.

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  • xforms "instance namespace" issue

    - by user302254
    I am creating an Xform that reads an XML document and creates an input form for updating the document. However, apparently due to a namespace issue none of my Xpath expressions resolve.My form works fine on a simple instance when the instance file has no namespace. However, I need the namespace support. My instance file has a namespace "ai:inventory." I am referencing the instance data Where should I be declaring the prefix "ai" for my namespace so that my XPath expressions can find the appropriate elements? /ai:inventory/products ? I've tried creating the prefix in the html opening tag... that didn't help. thanks,

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  • How to Create a Temporary Function in Emacs Lisp

    - by Cristian
    I'm making some tedious calls to a bunch of functions, but the parameters will be determined at runtime. I wrote a simple function to keep my code DRY but giving it a name is unnecessary. I don't use this function anywhere else. I'm trying to do it the way I would in Scheme, but I get a void-function error: (let ((do-work (lambda (x y z) (do-x x) (do-y y) ;; etc ))) (cond (test-1 (do-work 'a 'b 'c)) (test-2 (do-work 'i 'j 'k)))) I could stick it all into an apply (e.g., (apply (lambda ...) (cond ...))) but that isn't very readable. Is there a better way?

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  • Debugging dynamic sql + dynamic tables in MS SQL Server 2008.

    - by Hamish Grubijan
    Hi, I have a messy stored procedure which uses dynamic sql. I can debug it in runtime by adding print @sql; where @sql; is the string containing the dynamic SQL, right before I call execute (@sql);. Now, the multi-page stored procedure also creates dynamic tables and uses them in a query. I want to print those tables to the console right before I do an execute, so that I know exactly what the query is trying to do. However, the SQL Server 08 does not like that. When I try: print #temp_table; and try to compile the S.P. I get this error: The name "#temp_table" is not permitted in this context. Valid expressions are constants, constant expressions, and (in some contexts) variables. Column names are not permitted. Please help.

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  • Is this an F# quotations bug?

    - by ControlFlow
    [<ReflectedDefinition>] let rec x = (fun() -> x + "abc") () The sample code with the recursive value above produces the following F# compiler error: error FS0432: [<ReflectedDefinition>] terms cannot contain uses of the prefix splice operator '%' I can't see any slicing operator usage in the code above, looks like a bug... :) Looks like this is the problem with the quotation via ReflectedDefinitionAttribute only, normal quotation works well: let quotation = <@ let rec x = (fun() -> x + "abc") () in x @> produces expected result with the hidden Lazy.create and Lazy.force usages: val quotation : Quotations.Expr<string> = LetRecursive ([(x, Lambda (unitVar, Application (Lambda (unitVar0, Call (None, String op_Addition[String,String,String](String, String), [Call (None, String Force[String](Lazy`1[System.String]), [x]), Value ("abc")])), Value (<null>)))), (x, Call (None, Lazy`1[String] Create[String](FSharpFunc`2[Unit,String]), [x])), (x, Call (None, String Force[String](Lazy`1[String]), [x]))], x) So the question is: is this an F# compiler bug or not?

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  • Scipy Negative Distance? What?

    - by disappearedng
    I have a input file which are all floating point numbers to 4 decimal place. i.e. 13359 0.0000 0.0000 0.0001 0.0001 0.0002` 0.0003 0.0007 ... (the first is the id). My class uses the loadVectorsFromFile method which multiplies it by 10000 and then int() these numbers. On top of that, I also loop through each vector to ensure that there are no negative values inside. However, when I perform _hclustering, I am continually seeing the error, "Linkage Z contains negative values". I seriously think this is a bug because: I checked my values, the values are no where small enough or big enough to approach the limits of the floating point numbers and the formula that I used to derive the values in the file uses absolute value (my input is DEFINITELY right). Can someone enligten me as to why I am seeing this weird error? What is going on that is causing this negative distance error? ===== def loadVectorsFromFile(self, limit, loc, assertAllPositive=True, inflate=True): """Inflate to prevent "negative" distance, we use 4 decimal points, so *10000 """ vectors = {} self.winfo("Each vector is set to have %d limit in length" % limit) with open( loc ) as inf: for line in filter(None, inf.read().split('\n')): l = line.split('\t') if limit: scores = map(float, l[1:limit+1]) else: scores = map(float, l[1:]) if inflate: vectors[ l[0]] = map( lambda x: int(x*10000), scores) #int might save space else: vectors[ l[0]] = scores if assertAllPositive: #Assert that it has no negative value for dirID, l in vectors.iteritems(): if reduce(operator.or_, map( lambda x: x < 0, l)): self.werror( "Vector %s has negative values!" % dirID) return vectors def main( self, inputDir, outputDir, limit=0, inFname="data.vectors.all", mappingFname='all.id.features.group.intermediate'): """ Loads vector from a file and start clustering INPUT vectors is { featureID: tfidfVector (list), } """ IDFeatureDic = loadIdFeatureGroupDicFromIntermediate( pjoin(self.configDir, mappingFname)) if not os.path.exists(outputDir): os.makedirs(outputDir) vectors = self.loadVectorsFromFile( limit, pjoin( inputDir, inFname)) for threshold in map( lambda x:float(x)/30, range(20,30)): clusters = self._hclustering(threshold, vectors) if clusters: outputLoc = pjoin(outputDir, "threshold.%s.result" % str(threshold)) with open(outputLoc, 'w') as outf: for clusterNo, cluster in clusters.iteritems(): outf.write('%s\n' % str(clusterNo)) for featureID in cluster: feature, group = IDFeatureDic[featureID] outline = "%s\t%s\n" % (feature, group) outf.write(outline.encode('utf-8')) outf.write("\n") else: continue def _hclustering(self, threshold, vectors): """function which you should call to vary the threshold vectors: { featureID: [ tfidf scores, tfidf score, .. ] """ clusters = defaultdict(list) if len(vectors) > 1: try: results = hierarchy.fclusterdata( vectors.values(), threshold, metric='cosine') except ValueError, e: self.werror("_hclustering: %s" % str(e)) return False for i, featureID in enumerate( vectors.keys()):

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  • Determining whether values can potentially match a regular expression, given more input

    - by Andreas Grech
    I am currently writing an application in JavaScript where I'm matching input to regular expressions, but I also need to find a way how to match strings to parts of the regular expressions. For example: var invalid = "x", potentially = "g", valid = "ggg", gReg = /^ggg$/; gReg.test(invalid); //returns false (correct) gReg.test(valid); //returns true (correct) Now I need to find a way to somehow determine that the value of the potentially variable doesn't exactly match the /^ggg$/ expression, BUT with more input, it potentially can! So for example in this case, the potentially variable is g, but if two more g's are appended to it, it will match the regular expression /^ggg$/ But in the case of invalid, it can never match the /^ggg$/ expression, no matter how many characters you append to it. So how can I determine if a string has or doesn't have potential to match a particular regular expression?

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  • PyQt: How to keep QTreeView nodes correctly expanded after a sort

    - by taynaron
    I'm writing a simple test program using QTreeModel and QTreeView for a more complex project later on. In this simple program, I have data in groups which may be contracted or expanded, as one would expect in a QTreeView. The data may also be sorted by the various data columns (QTreeView.setSortingEnabled is True). Each tree item is a list of data, so the sort function implemented in the TreeModel class uses the built-in python list sort: self.layoutAboutToBeChanged.emit() self.rootItem.childItems.sort(key=lambda x: x.itemData[col], reverse=order) for item in self.rootItem.childItems: item.childItems.sort(key=lambda x: x.itemData[col], reverse=order) self.layoutChanged.emit() The problem is that whenever I change the sorting of the root's child items (the tree is only 2 levels deep, so this is the only level with children) the nodes aren't necessarily expanded as they were before. If I change the sorting back without expanding or collapsing anything, the nodes are expanded as before the sorting change. Can anyone explain to me what I'm doing wrong? I suspect it's something with not properly reassigning QModelIndex with the sorted nodes, but I'm not sure.

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  • Catch all exceptions in Scala 2.8 RC1

    - by Michel Krämer
    I have the following dummy Scala code in the file test.scala: class Transaction { def begin() {} def commit() {} def rollback() {} } object Test extends Application { def doSomething() {} val t = new Transaction() t.begin() try { doSomething() t.commit() } catch { case _ => t.rollback() } } If I compile this on Scala 2.8 RC1 with scalac -Xstrict-warnings test.scala I'll get the following warning: test.scala:16: warning: catch clause swallows everything: not advised. case _ => t.rollback() ^ one warning found So, if catch-all expressions are not advised, how am I supposed to implement such a pattern instead? And apart from that why are such expressions not advised anyhow?

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  • varchar comparison in SQL Server

    - by Ram
    I am looking for some SQL varchar comparison function like C# string.compare (we can ignore case for now, should return zero when the character expression are same and a non zero expression when they are different) Basically I have some alphanumeric column in one table which needs to be verified in another table. I cannot do select A.col1 - B.col1 from (query) as "-" operator cannot be applied on character expressions I cannot cast my expression as int (and then do a difference/subtraction) as it fails select cast ('ASXT000R' as int) Conversion failed when converting varchar 'ASXT000R' to int Soundex would not do it as soundex is same for 2 similar strings Difference would not do it as select difference('abc','ABC') = 4 (as per msdn, difference is the difference in the soundex of 2 character expressions and difference =4 implies least different) Is there any other way of doing it ?

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  • Help with Django localization--doesn't seem to be working. Nothing happens

    - by alex
    Can someone help me with Localization? I put {% trans "..." %} in my template, I filled in my django.po after running "makemessages". #: templates/main_content.html:136 msgid "Go to page" msgstr "¦~C~Z¦~C¦¦~B¦¦~L~G¦~Z" #: templates/main_content.html:138 msgid "Page" msgstr "¦~C~Z¦~C¦¦~B¦" #: templates/main_content.html:154 msgid "Next" msgstr "?" Then, I set LANGUAGES={} in my settings.py along with "gettext lambda": gettext = lambda s: s LANGUAGES = ( ('de', gettext('German')), ('en', gettext('English')), ('ja', gettext('Japanese')), ) Of course, I installed the LocaleMiddleware. I also set the request.session['django_language'] = "ja" How do I test that this is working? How do I see japanese on my site!?

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  • Write Scheme data structures so they can be eval-d back in, or alternative

    - by Jesse Millikan
    I'm writing an application (A juggling pattern animator) in PLT Scheme that accepts Scheme expressions as values for some fields. I'm attempting to write a small text editor that will let me "explode" expressions into expressions that can still be eval'd but contain the data as literals for manual tweaking. For example, (4hss->sexp "747") is a function call that generates a legitimate pattern. If I eval and print that, it becomes (((7 3) - - -) (- - (4 2) -) (- (7 2) - -) (- - - (7 1)) ((4 0) - - -) (- - (7 0) -) (- (7 2) - -) (- - - (4 3)) ((7 3) - - -) (- - (7 0) -) (- (4 1) - -) (- - - (7 1))) which can be "read" as a string, but will not "eval" the same as the function. For this statement, of course, what I need would be as simple as (quote (((7 3... but other examples are non-trivial. This one, for example, contains structs which print as vectors: pair-of-jugglers ; --> (#(struct:hand #(struct:position -0.35 2.0 1.0) #(struct:position -0.6 2.05 1.1) 1.832595714594046) #(struct:hand #(struct:position 0.35 2.0 1.0) #(struct:position 0.6 2.0500000000000003 1.1) 1.308996938995747) #(struct:hand #(struct:position 0.35 -2.0 1.0) #(struct:position 0.6 -2.05 1.1) -1.3089969389957472) #(struct:hand #(struct:position -0.35 -2.0 1.0) #(struct:position -0.6 -2.05 1.1) -1.8325957145940461)) I've thought of at least three possible solutions, none of which I like very much. Solution A is to write a recursive eval-able output function myself for a reasonably large subset of the values that I might be using. There (probably...) won't be any circular references by the nature of the data structures used, so that wouldn't be such a long job. The output would end up looking like `(((3 0) (... ; ex 1 `(,(make-hand (make-position ... ; ex 2 Or even worse if I could't figure out how to do it properly with quasiquoting. Solution B would be to write out everything as (read (open-input-string "(big-long-s-expression)")) which, technically, solves the problem I'm bringing up but is... ugly. Solution C might be a different approach of giving up eval and using only read for parsing input, or an uglier approach where the s-expression is used as directly data if eval fails, but those both seem unpleasant compared to using scheme values directly. Undiscovered Solution D would be a PLT Scheme option, function or library I haven't located that would match Solution A. Help me out before I start having bad recursion dreams again.

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  • executing named_scoped only when there are present params

    - by Luca Romagnoli
    Hi have a model like this: class EventDate < ActiveRecord::Base belongs_to :event named_scope :named, lambda { | name | { :joins => { :event => :core}, :conditions => ["name like ?", "%#{ name }%"] }} named_scope :date_range, lambda { | start, length | { :conditions => ["day >= ? AND day <= ?", start, date + (length || 30) ] }} it works correctly if i launch name = "ba" start = Date.today EventDate.named(name).date_range(start , start + 2) But if the name or the start is nil i don't want execute the named_scope like name = nil EventDate.named(name).date_range(start , start + 2) Is possible to set a condition inner the named_scope ? thanks

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  • Is it possible to change where things are in Chrome's Developer Tools Script panel?

    - by T.J. Crowder
    When debugging browser-based apps using Google Chrome's Developer Tools, is there a way to change the locations of the various panes? Specifically in the Scripts panel (though I suppose it's a general question). E.g., the Watch Expressions, the Call Stack, the code pane, etc.? The defaults are okay (console at bottom, code pane upper left, a column of Watch Expressions, Call Stack, Scope Vars, etc. in the upper right), but I'd rather swap things around a bit if it's possible. There doesn't seem to be anything to grab (other than for sizing) and I haven't found a way in my searching so far, but there are (still) some things about Chrome's options that aren't ... well-advertised in the UI, shall we say :-), especially around developer tools.

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  • How do you sort files numerically?

    - by Zachary Young
    Hello all, First off, I'm posting this because when I was looking for a solution to the problem below, I could not find one on stackoverflow. So, I'm hoping to add a little bit to the knowledge base here. I need to process some files in a directory and need the files to be sorted numerically. I found some examples on sorting--specifically with using the lamba pattern--at wiki.python.org, and I put this together: #!env/python import re tiffFiles = """ayurveda_1.tif ayurveda_11.tif ayurveda_13.tif ayurveda_2.tif ayurveda_20.tif ayurveda_22.tif""".split('\n') numPattern = re.compile('_(\d{1,2})\.', re.IGNORECASE) tiffFiles.sort(cmp, key=lambda tFile: int(numPattern.search(tFile).group(1))) print tiffFiles I'm still rather new to Python and would like to ask the community if there are any improvements that can be made to this: shortening the code up (removing lambda), performance, style/readability? Thank you, Zachary

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  • regular expression search in python

    - by Richard
    Hello all, I am trying to parse some data and just started reading up on regular Expressions so I am pretty new to it. This is the code I have so far String = "MEASUREMENT 3835 303 Oxygen: 235.78 Saturation: 90.51 Temperature: 24.41 DPhase: 33.07 BPhase: 29.56 RPhase: 0.00 BAmp: 368.57 BPot: 18.00 RAmp: 0.00 RawTem.: 68.21" String = String.strip('\t\x11\x13') String = String.split("Oxygen:") print String[1] String[1].lstrip print String[1] What I am trying to do is to do is remove the oxygen data (235.78) and put it in its own variable using an regular expression search. I realize that there should be an easy solution but I am trying to figure out how regular expressions work and they are making my head hurt. Thanks for any help Richard

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  • Using Python tuples as vectors

    - by Etaoin
    I need to represent immutable vectors in Python ("vectors" as in linear algebra, not as in programming). The tuple seems like an obvious choice. The trouble is when I need to implement things like addition and scalar multiplication. If a and b are vectors, and c is a number, the best I can think of is this: tuple(map(lambda x,y: x + y, a, b)) # add vectors 'a' and 'b' tuple(map(lambda x: x * c, a)) # multiply vector 'a' by scalar 'c' which seems inelegant; there should be a clearer, simpler way to get this done -- not to mention avoiding the call to tuple, since map returns a list. Is there a better option?

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  • Is this code well-defined?

    - by Nawaz
    This code is taken from a discussion going on here. someInstance.Fun(++k).Gun(10).Sun(k).Tun(); Is this code well-defined? Is ++k Fun() evaluated before k in Sun()? What if k is user-defined type, not built-in type? And in what ways the above function calls order is different from this: eat(++k);drink(10);sleep(k); As far as I can say, in both situations, there exists a sequence point after each function call. If so, then why can't the first case is also well-defined like the second one? Section 1.9.17 of the C++ ISO standard says this about sequence points and function evaluation: When calling a function (whether or not the function is inline), there is a sequence point after the evaluation of all function arguments (if any) which takes place before execution of any expressions or statements in the function body. There is also a sequence point after the copying of a returned value and before the execution of any expressions outside the function.

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  • web2py error while using distinct in the queries

    - by Steve
    Hi, I am using web2py with GAE. While using some of the queries which has a distinct clause, GAE throws out an error.I have pasted the Traceback. Can someone please help me out with this. In FILE: /base/data/home/apps/panneersoda/1.341206242889687944/applications/init/controllers/default.py Traceback (most recent call last): File "/base/data/home/apps/panneersoda/1.341206242889687944/gluon/restricted.py", line 173, in restricted exec ccode in environment File "/base/data/home/apps/panneersoda/1.341206242889687944/applications/init/controllers/default.py:profileview", line 263, in <module> File "/base/data/home/apps/panneersoda/1.341206242889687944/gluon/globals.py", line 96, in <lambda> self._caller = lambda f: f() File "/base/data/home/apps/panneersoda/1.341206242889687944/applications/init/controllers/default.py:profileview", line 97, in profileview File "/base/data/home/apps/panneersoda/1.341206242889687944/gluon/contrib/gql.py", line 675, in select (items, tablename, fields) = self._select(*fields, **attributes) File "/base/data/home/apps/panneersoda/1.341206242889687944/gluon/contrib/gql.py", line 624, in _select raise SyntaxError, 'invalid select attribute: %s' % key SyntaxError: invalid select attribute: distinct Thanks

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  • Consolidating coding styles: Funcs, private method, single method classes

    - by jdoig
    Hi all, We currently have 3 devs with, some, conflicting styles and I'm looking for a way to bring peace to the kingdom... The Coders: Foo 1: Likes to use Func's & Action's inside public methods. He uses actions to alias off lengthy method calls and Func's to perform simple tasks that can be expressed in 1 or 2 lines and will be used frequently through out the code Pros: The main body of his code is succinct and very readable, often with only one or 2 public methods per class and rarely any private methods. Cons: The start of methods contain blocks of lambda rich code that other developers don't enjoy reading; and, on occasion, can contain higher order functions that other dev's REALLY don't like reading. Foo 2: Likes to create a private method for (almost) everything the public method will have to do . Pros: Public methods remain small and readable (to all developers). Cons: Private methods are numerous. With private methods that call into other private methods, that call into... etc, etc. Making code hard to navigate. Foo 3: Likes to create a public class with a, single, public method for every, non-trivial, task that needs performing, then dependency inject them into other objects. Pros: Easily testable, easy to understand (one object, one responsibility). Cons: project gets littered by classes, opening multiple class files to understand what code does makes navigation awkward. It would be great to take the best of all these techniques... Foo-1 Has really nice, readable (almost dsl-like) code... for the most part, except for all the Action and Func lambda shenanigans bulked together at the start of a method. Foo-3 Has highly testable and extensible code that just feels a bit "belt-&-braces" for some solutions and has some code-navigation niggles (constantly hitting F12 in VS and opening 5 other .cs files to find out what a single method does). And Foo-2... Well I'm not sure I like anything about the one-huge .cs file with 2 public methods and 12 private ones, except for the fact it's easier for juniors to dig into. I admit I grossly over-simplified the explanations of those coding styles; but if any one knows of any patterns, practices or diplomatic-manoeuvres that can help unite our three developers (without just telling any of them to just "stop it!") that would be great. From a feasibility standpoint : Foo-1's style meets with the most resistance due to some developers finding lambda and/or Func's hard to read. Foo-2's style meets with a less resistance as it's just so easy to fall into. Foo-3's style requires the most forward thinking and is difficult to enforce when time is short. Any ideas on some coding styles or conventions that can make this work?

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  • How can this closure test be written in other languages?

    - by Jian Lin
    I wonder how the following closure test can be written in other languages, such as C and Java. Can the same result be expected also in Perl, Python, and PHP? Ideally, we don't need to make a new local variable such as x and assign it the value of i inside the loop, but just so that i has a new copy in the new scope each time. (if possible). (some discussion is in this question.) The following is in Ruby, the "1.8.6" on the first line of result is the Ruby version which can be ignored. p RUBY_VERSION $foo = [] (1..5).each do |i| $foo[i] = lambda { p i } end (1..5).each do |j| $foo[j].call() end the print out is: [MacBook01:~] $ ruby scope.rb "1.8.6" 1 2 3 4 5 [MacBook01:~] $ Contrast that with another test, with i defined outside: p RUBY_VERSION $foo = [] i = 0 (1..5).each do |i| $foo[i] = lambda { p i } end (1..5).each do |j| $foo[j].call() end the print out: [MacBook01:~] $ ruby scope2.rb "1.8.6" 5 5 5 5 5 [MacBook01:~] $

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  • whats wrong with this regular expression c#?

    - by Greezer
    I runned into a problem with my regular expressions, I'm using regular expressions for obtaining data from the string below: "# DO NOT EDIT THIS MAIL BY HAND #\r\n\r\n[Feedback]:hallo\r\n\r\n# DO NOT EDIT THIS MAIL BY HAND #\r\n\r\n" So far is got it working with: String sFeedback = Regex.Match(Message, @"\[Feedback\]\:(?<string>.*?)\r\n\r\t\n# DO NOT EDIT THIS MAIL BY HAND #").Groups[1].Value; This works except if the header is changed, therefore I want the regex to read from [feedback]: to the end of the string. (symbols, ascii, everything..) I tried: \[Feedback]:(?<string>.*?)$ Above regular expression does work in some regular expression builders online but in my c# code its not working and returns a empty string. can someone help me with this regular expression? thanks in advance

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