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c# var

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  • O obermd

    GuyThiebaut wrote:

    The advantage of var is if "http://someapi" was a variable or class instance instead of a string literal and you changed its type, you would not then need to refactor the code elsewhere.

    Absolutely not true. Changing a data type and then attempting to use it elsewhere is guaranteed to cause you to have to modify code everywhere it's used. Fortunately the VS IDE is smart enough to identify those spots for you.

    G Offline
    G Offline
    GuyThiebaut
    wrote on last edited by
    #15

    obermd wrote:

    Absolutely not true. Changing a data type and then attempting to use it elsewhere is guaranteed to cause you to have to modify code everywhere it's used.

    Even when changing from a short to a long?

    “That which can be asserted without evidence, can be dismissed without evidence.”

    ― Christopher Hitchens

    1 Reply Last reply
    0
    • Z ZurdoDev

      What is the love affair with var? I see sample code where they do something like

      var url = "http://someapi";

      This feels lazy to me but I am open minded and am curious if I am missing something. Is there some benefit to declaring most things var instead of what they actually are? In the case above, a string.

      Social Media - A platform that makes it easier for the crazies to find each other. Everyone is born right handed. Only the strongest overcome it. Fight for left-handed rights and hand equality.

      W Offline
      W Offline
      Wendelius
      wrote on last edited by
      #16

      I rarely use var but I do use it when returning a tuple from a method to avoid out parameters. For example

      void MainMethod() {
      ...
      var methodCall = SomeMethod();
      if (!methodCall.Success) {
      return;
      }
      ...
      }

      (bool Success, int? ReturnValue) SomeMethod() {
      int? retValue;

      ...
      if (...) {
      return (Success: false, ReturnValue: null);
      }
      ...

      return (Success: true, ReturnValue: retValue):
      }

      Richard DeemingR 1 Reply Last reply
      0
      • OriginalGriffO OriginalGriff

        I'd actually prefer it is you could do this:

        Dictionary> complicatedDictionary = new *();

        To me, that would be a more natural way of showing what the type of complicatedDictionary actually is. As it is, I find var is mainly over used by the lazy-and-don't-care script kiddies ...

        "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony AntiTwitter: @DalekDave is now a follower!

        Richard DeemingR Offline
        Richard DeemingR Offline
        Richard Deeming
        wrote on last edited by
        #17

        That should hopefully be coming in C# 9: csharplang/target-typed-new.md at master · dotnet/csharplang · GitHub[^] Champion "Target-typed `new` expression" · Issue #100 · dotnet/csharplang · GitHub[^] Edit: As already mentioned in the Insider News[^]. :)


        "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

        "These people looked deep within my soul and assigned me a number based on the order in which I joined" - Homer

        OriginalGriffO 1 Reply Last reply
        0
        • W Wendelius

          I rarely use var but I do use it when returning a tuple from a method to avoid out parameters. For example

          void MainMethod() {
          ...
          var methodCall = SomeMethod();
          if (!methodCall.Success) {
          return;
          }
          ...
          }

          (bool Success, int? ReturnValue) SomeMethod() {
          int? retValue;

          ...
          if (...) {
          return (Success: false, ReturnValue: null);
          }
          ...

          return (Success: true, ReturnValue: retValue):
          }

          Richard DeemingR Offline
          Richard DeemingR Offline
          Richard Deeming
          wrote on last edited by
          #18

          Or better yet:

          var (Success, ReturnValue) = SomeMethod();
          if (!Success) {
          return;
          }


          "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

          "These people looked deep within my soul and assigned me a number based on the order in which I joined" - Homer

          1 Reply Last reply
          0
          • Richard DeemingR Richard Deeming

            That should hopefully be coming in C# 9: csharplang/target-typed-new.md at master · dotnet/csharplang · GitHub[^] Champion "Target-typed `new` expression" · Issue #100 · dotnet/csharplang · GitHub[^] Edit: As already mentioned in the Insider News[^]. :)


            "These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

            OriginalGriffO Offline
            OriginalGriffO Offline
            OriginalGriff
            wrote on last edited by
            #19

            Hah! I just spent half an hour trying to persuade Google to let me know how you make suggestions for the C# spec ... :laugh: That language change I will use!

            "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony AntiTwitter: @DalekDave is now a follower!

            "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
            "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt

            1 Reply Last reply
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            • Z ZurdoDev

              What is the love affair with var? I see sample code where they do something like

              var url = "http://someapi";

              This feels lazy to me but I am open minded and am curious if I am missing something. Is there some benefit to declaring most things var instead of what they actually are? In the case above, a string.

              Social Media - A platform that makes it easier for the crazies to find each other. Everyone is born right handed. Only the strongest overcome it. Fight for left-handed rights and hand equality.

              P Offline
              P Offline
              Pete OHanlon
              wrote on last edited by
              #20

              Ah, the use of var. I know that some people use var to do code alignment on variable names; the idea being that it's easier to scan the name if it lines up.

              private void DoSomething()
              {
              var apiEndpoint = new Uri("http://someapi");
              var retryCount = 10;
              var longClassName = new ThisIsAReallyLongNameThatWouldReallyScrewUpTheClassNameDeclaration();
              // body of the method.
              }

              Advanced TypeScript Programming Projects

              N 1 Reply Last reply
              0
              • F F ES Sitecore

                The only benefit is that if you don't understand types then there is a chance your code will work using var even though you don't know why. Also I've found some common style tools dictate you should use var. I don't mind it for

                var name = "Blah";

                or

                var people = new List();

                but I hate it when people use it for things like

                var data = SomeFunction();

                M Offline
                M Offline
                megaadam
                wrote on last edited by
                #21

                In C++

                auto i = small integer // seems rather silly, and obscures signed/unsigned
                auto v = some complex STL type // is handy
                auto l = some big elephanting lambda // is required, and why they added it

                "If we don't change direction, we'll end up where we're going"

                1 Reply Last reply
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                • OriginalGriffO OriginalGriff

                  I'd actually prefer it is you could do this:

                  Dictionary> complicatedDictionary = new *();

                  To me, that would be a more natural way of showing what the type of complicatedDictionary actually is. As it is, I find var is mainly over used by the lazy-and-don't-care script kiddies ...

                  "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony AntiTwitter: @DalekDave is now a follower!

                  N Offline
                  N Offline
                  Nelek
                  wrote on last edited by
                  #22

                  I kind of find it easier to read with var first. But this is more secure, since you have to know what you are going to need and the you create the new instance in the lazy mode. Best of both options, I guess

                  M.D.V. ;) If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about? Help me to understand what I'm saying, and I'll explain it better to you Rating helpful answers is nice, but saying thanks can be even nicer.

                  1 Reply Last reply
                  0
                  • OriginalGriffO OriginalGriff

                    I'd actually prefer it is you could do this:

                    Dictionary> complicatedDictionary = new *();

                    To me, that would be a more natural way of showing what the type of complicatedDictionary actually is. As it is, I find var is mainly over used by the lazy-and-don't-care script kiddies ...

                    "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony AntiTwitter: @DalekDave is now a follower!

                    M Offline
                    M Offline
                    Marc Clifton
                    wrote on last edited by
                    #23

                    OriginalGriff wrote:

                    that would be a more natural way of showing what the type

                    Yup. And as I replied on the Insider News, what I really want is: var foo = new(); In most cases, the compiler should be able to figure out what foo is by inspecting its usage in the code! :laugh:

                    Latest Articles:
                    Abusing Extension Methods, Null Continuation, and Null Coalescence Operators

                    B 1 Reply Last reply
                    0
                    • P Pete OHanlon

                      Ah, the use of var. I know that some people use var to do code alignment on variable names; the idea being that it's easier to scan the name if it lines up.

                      private void DoSomething()
                      {
                      var apiEndpoint = new Uri("http://someapi");
                      var retryCount = 10;
                      var longClassName = new ThisIsAReallyLongNameThatWouldReallyScrewUpTheClassNameDeclaration();
                      // body of the method.
                      }

                      Advanced TypeScript Programming Projects

                      N Offline
                      N Offline
                      Nelek
                      wrote on last edited by
                      #24

                      Pete O'Hanlon wrote:

                      the idea being that it's easier to scan the name if it lines up.

                      :thumbsup::thumbsup: That's my main argument (readability) and why I like it. On the other hand, incoming Option #3[^] is good too. It is a bit less readable, but still "forces" you to by type strong but combined with the lazyness / don't break the lines with long names too.

                      M.D.V. ;) If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about? Help me to understand what I'm saying, and I'll explain it better to you Rating helpful answers is nice, but saying thanks can be even nicer.

                      1 Reply Last reply
                      0
                      • Z ZurdoDev

                        What is the love affair with var? I see sample code where they do something like

                        var url = "http://someapi";

                        This feels lazy to me but I am open minded and am curious if I am missing something. Is there some benefit to declaring most things var instead of what they actually are? In the case above, a string.

                        Social Media - A platform that makes it easier for the crazies to find each other. Everyone is born right handed. Only the strongest overcome it. Fight for left-handed rights and hand equality.

                        R Offline
                        R Offline
                        rnbergren
                        wrote on last edited by
                        #25

                        is it lazy. Sure is. Does it work. Unfortunately yes and Fortunately yes. AS mentioned already when refactoring code and say a variable changes from int to long or even to a string it makes sure the code continues to work. I don't like it. but that does not mean I have never used it. I have and I hate myself for it. But I remember one time I had to write a bit of code. The co-workers insisted that the variable would always be an integer. ALWAYS they said. having some experience I knew probably gonna change. About a year later system requirements changed. I had used var and the code still worked. sooooooo tldr; lazy yes, flexible yes, hate myself yes.

                        To err is human to really mess up you need a computer

                        OriginalGriffO 1 Reply Last reply
                        0
                        • S Slacker007

                          it is good for a lot of applications but can be missused very easily. it's main purpose is code readability.

                          MyMostExcellentBaseClassOfAllClassesInTheWholeWorld myClass = new MyMostExcellentBaseClassOfAllClassesInTheWholeWorld();

                          or

                          var myClass = new MyMostExcellentBaseClassOfAllClassesInTheWholeWorld();

                          It is really good when working with Linq, etc. as well.

                          F Offline
                          F Offline
                          F ES Sitecore
                          wrote on last edited by
                          #26

                          Slacker007 wrote:

                          it's main purpose is code readability.

                          Its main purpose is actually anonymous types.

                          S 1 Reply Last reply
                          0
                          • F F ES Sitecore

                            Slacker007 wrote:

                            it's main purpose is code readability.

                            Its main purpose is actually anonymous types.

                            S Offline
                            S Offline
                            Slacker007
                            wrote on last edited by
                            #27

                            I guess it could be used for both, but most people use it for implicit, which by nature adds to code readability for most. Edit: implicit and anonymous. but when I use it, I am not thinking "anonymous" or "Implicit" etc, I am thinking code readability. var - C# Reference | Microsoft Docs[^] c# - Implicitly Typed vs Anonymous Type - Stack Overflow[^]

                            1 Reply Last reply
                            0
                            • R rnbergren

                              is it lazy. Sure is. Does it work. Unfortunately yes and Fortunately yes. AS mentioned already when refactoring code and say a variable changes from int to long or even to a string it makes sure the code continues to work. I don't like it. but that does not mean I have never used it. I have and I hate myself for it. But I remember one time I had to write a bit of code. The co-workers insisted that the variable would always be an integer. ALWAYS they said. having some experience I knew probably gonna change. About a year later system requirements changed. I had used var and the code still worked. sooooooo tldr; lazy yes, flexible yes, hate myself yes.

                              To err is human to really mess up you need a computer

                              OriginalGriffO Offline
                              OriginalGriffO Offline
                              OriginalGriff
                              wrote on last edited by
                              #28

                              The problem with that is that you are working to what should have been a breaking change. And that's important, because if you were assuming int division as a result of the original type spec for example, then a breaking change means you know it's just failed and can adapt to it. var in that case means you don't know, and output can be subtly wrong and unnoticed until it's a real problem. I'd say var should be there for temporary storage of Linq results, and nowhere else ...

                              "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony AntiTwitter: @DalekDave is now a follower!

                              "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
                              "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt

                              pkfoxP 1 Reply Last reply
                              0
                              • Z ZurdoDev

                                What is the love affair with var? I see sample code where they do something like

                                var url = "http://someapi";

                                This feels lazy to me but I am open minded and am curious if I am missing something. Is there some benefit to declaring most things var instead of what they actually are? In the case above, a string.

                                Social Media - A platform that makes it easier for the crazies to find each other. Everyone is born right handed. Only the strongest overcome it. Fight for left-handed rights and hand equality.

                                P Offline
                                P Offline
                                PIEBALDconsult
                                wrote on last edited by
                                #29

                                That's just pure laziness.

                                1 Reply Last reply
                                0
                                • M Marc Clifton

                                  ZurdoDev wrote:

                                  This feels lazy to me but I am open minded and am curious if I am missing something. Is there some benefit to declaring most things var instead of what they actually are? In the case above, a string.

                                  I felt the same way initially, and I agree, for something simple like a native type, I rarely use var. However: var complicatedDictionary = new Dictionary>(); and worse, I like definitely like it.

                                  Latest Articles:
                                  Abusing Extension Methods, Null Continuation, and Null Coalescence Operators

                                  D Offline
                                  D Offline
                                  dandy72
                                  wrote on last edited by
                                  #30

                                  +1 For native types, I don't see the point in using var. I also subscribe to the idea of using: var x = new SomeMoreComplexType(); I don't mind: var x = SomeFunction(); ...if *I* don't particularly case about the type returned, for example, if I only use it to forward to some other function and I'm not looking at any of its members myself.

                                  1 Reply Last reply
                                  0
                                  • Z ZurdoDev

                                    What is the love affair with var? I see sample code where they do something like

                                    var url = "http://someapi";

                                    This feels lazy to me but I am open minded and am curious if I am missing something. Is there some benefit to declaring most things var instead of what they actually are? In the case above, a string.

                                    Social Media - A platform that makes it easier for the crazies to find each other. Everyone is born right handed. Only the strongest overcome it. Fight for left-handed rights and hand equality.

                                    M Offline
                                    M Offline
                                    MadMyche
                                    wrote on last edited by
                                    #31

                                    ZurdoDev wrote:

                                    var url = "http://someapi";

                                    Is there some benefit to declaring most things var instead of what they actually are? In the case above, a string.

                                    Is it a string? Could it be a URI[^]

                                    Uri siteUri = new Uri("http://www.contoso.com/");

                                    Director of Transmogrification Services Shinobi of Query Language Master of Yoda Conditional

                                    Z 1 Reply Last reply
                                    0
                                    • M MadMyche

                                      ZurdoDev wrote:

                                      var url = "http://someapi";

                                      Is there some benefit to declaring most things var instead of what they actually are? In the case above, a string.

                                      Is it a string? Could it be a URI[^]

                                      Uri siteUri = new Uri("http://www.contoso.com/");

                                      Director of Transmogrification Services Shinobi of Query Language Master of Yoda Conditional

                                      Z Offline
                                      Z Offline
                                      ZurdoDev
                                      wrote on last edited by
                                      #32

                                      Yes, it was a string.

                                      Social Media - A platform that makes it easier for the crazies to find each other. Everyone is born right handed. Only the strongest overcome it. Fight for left-handed rights and hand equality.

                                      M 1 Reply Last reply
                                      0
                                      • Greg UtasG Greg Utas

                                        I use auto, the C++ equivalent, whenever it will deduce the correct type. - It forces you to initialize the variable. - If the variable is initialized by calling a function, and that function's return type changes, the code might not even be affected. - Some type names are long or complicated, and I hate spilling lines. Some argue that it makes the code harder to understand because the reader has to figure out the type. My counterargument is that the reader doesn't understand how the code fits into the system if this is the case.

                                        Robust Services Core | Software Techniques for Lemmings | Articles

                                        M Offline
                                        M Offline
                                        Mircea Neacsu
                                        wrote on last edited by
                                        #33

                                        You are going on a dangerous path. It leads you to the days when an insignificant dot was significant:

                                        auto i = 2;
                                        auto j = 3;
                                        auto k = i/j;
                                        auto f = 2./j;
                                        // f != k
                                        // any similarity with FORTRAN is intentional

                                        Besides "auto" has four letters and "int" has three; it's not energy efficient :)

                                        Mircea

                                        Greg UtasG 1 Reply Last reply
                                        0
                                        • M Mircea Neacsu

                                          You are going on a dangerous path. It leads you to the days when an insignificant dot was significant:

                                          auto i = 2;
                                          auto j = 3;
                                          auto k = i/j;
                                          auto f = 2./j;
                                          // f != k
                                          // any similarity with FORTRAN is intentional

                                          Besides "auto" has four letters and "int" has three; it's not energy efficient :)

                                          Mircea

                                          Greg UtasG Offline
                                          Greg UtasG Offline
                                          Greg Utas
                                          wrote on last edited by
                                          #34

                                          Not very dangerous unless one ignores compiler warnings. Then again, I don't use floating point very often. The main one I have to watch for is

                                          for(auto i = 0...

                                          which makes i an int when what might actually be called for is a size_t.

                                          Robust Services Core | Software Techniques for Lemmings | Articles

                                          <p><a href="https://github.com/GregUtas/robust-services-core/blob/master/README.md">Robust Services Core</a>
                                          <em>The fox knows many things, but the hedgehog knows one big thing.</em></p>

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