Golang Cast Interface To String

Let’s take a look at some examples of using the CAST() function. Here is a simple snippet how to convert a string into a boolean type in Golang. It is followed by the name of the type (Person) and the keyword struct to indicate that we're defining a struct. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected] The service receives a Go program, vets, compiles, links, and runs the program inside a sandbox, then returns the output. Creating a Simple Web Application using Golang Steffi Indrayani/135140631 Computer Science/Informatics School of Electrical Engineering and Informatics Institut Teknologi Bandung, Jl. Interfaces are named collections of methods: type Shape interface { area() float64 } So, in the above code, the Shape interface has a method called area(). 510000e+01 string 45. Go (GoLang) tutorial in form of a daily blog, starting with beginner tasks like setting up a go workspace and then moving on to more complex things. Yes My main overall impression of Go is that its design feels arbitrary: its features are just whatever the designers felt like adding, however they felt like making them. Meanwhile, the Golang-nuts Google Group is quite active and is staffed by a cadre of passionate golang fans. json is one of the most wildly used Go packages. // NB: whenever using 'named' return values, they are (1) automatically defined with their default values and; // (2) we must use parenthesis around them to let Go know what we're up to! func getMyFavoriteNumber() (num int, reason string) { // Since Go defined `num` and `reason` from the function signature above, we can use the assignment. You can convert values from one type to another using the cast operator as following: type_name(expression) Question 13. Let me give a recap for the beginners out there. The type is asserted from this interface{} type as is needed in the code. If this is not defined, or is the empty string, no conversion is done. golang type casting from interface int32 to int You received this message because you are subscribed to the Google Groups "golang-nuts" group. Even though each value in vals is of type {}, the underlying type is still what it started out as. Slice is basically a pointer, with additional properties about the array. Lets say you have an interface in Golang, and for some reason you want to cast it. Package strconv implements conversions to and from string representations of basic data types. Go interfaces were designed after protocols from the Smalltalk programming language. Let’s put that on the shelf and detour into dispatch. Interfaces are named collections of methods: type Shape interface { area() float64 } So, in the above code, the Shape interface has a method called area(). We can add another method called perimeter like this: type Shape interface { area() float64 perimeter() float64 } In the following sample, we will see a basic interface for geometric shapes. Casting and Converting Objects and Primitive Types. When I first started programming in Go, my summary of it was, “The good things are great and the bad things are weird and I can live with them. Golang online course 1. 100000 string 4. Ganesha 10 Bandung 40132, Indonesia [email protected] Benchmarks will likely not be supported since the program runs. The fmt package (and many others) look for this interface to print values. The logic is simple. json is one of the most wildly used Go packages. Tools for Golang. Type casting means conversion of a variable from one data type to another. Cara casting objek interface sedikit unik, yaitu dengan menuliskan nama tipe tujuan dalam kurung, ditempatkan setelah nama interface dengan menggunakan notasi titik (seperti cara mengakses property, hanya saja ada tanda kurung nya). Type Casting or Type Conversion in Golang Multiple Interfaces in Golang In Go language, the interface is a collection of method signatures and it is also a type means you can create a variable of an interface type. First things first. Sometimes, you may want to know the exact type of an interface variable. 作者: 一字马胡 转载标志 【2017-11-21】 更新日志 准备环境 在Mac下,可以使用下面的命令安装golang: 完成安装之后,可以命令“go version”来. I offer a bounty of one coffee, beer, or tea for each pull request that gets merged in. , you can sort the elements on the basis of single data member only. // NB: whenever using 'named' return values, they are (1) automatically defined with their default values and; // (2) we must use parenthesis around them to let Go know what we're up to! func getMyFavoriteNumber() (num int, reason string) { // Since Go defined `num` and `reason` from the function signature above, we can use the assignment. Interfaces are implemented implicitly in Go. Important: the generic implementation of the data structure above compiles and can be tested as easily as a concrete implementation generated by go generate, so we can run tests against our generic implementation, as well as the type-specific ones. We will work out an example that uses Go's idea of interfaces, which is different from interfaces in programming languages like Java, C++, C#, etc. Then we can take an element (which will be again interface{} type). MySQL CAST function examples. 4k Golang : Get remaining text such as id or filename after last segment in URL path +4. In programming, interfaces follow a similar model. In Haskell:. To a large extent you can deal with this interface rather. cannot use tlist (type []Type) as type []Interface in assignment. Now let’s create 2 different type of animals which implement the animal interface type:. What does that even mean? Imagine a Car, or a Motorbike. This post will cover a small sample about how to capture or recover from panic in Golang. Golang allows you to name the return values of a function. Importing packages. There are two forms, Raw string literals: The value of raw string literals are character sequence between back quotes ''. Or, you can also use type casting to cast this string into a rune array. The most common numeric conversions are Atoi (string to int) and Itoa (int to string). Go (GoLang) tutorial in form of a daily blog, starting with beginner tasks like setting up a go workspace and then moving on to more complex things. When you use database like MySQL, MariaDB or SQLite, you can't use array fields unlike in Postgres or MongoDB. Multiple sources use the term duck typing when describing Go interfaces. Many times I have wanted to use generics to create small container types around other arbitrary things. So if any changes take place in the interface 1 and interface 2's methods it will reflect in interface 3. In the previous post "A Closer Look at Golang From an Architect's Perspective," we offered a high level look at the Go programming language. So, in Go inheritance. Is there any way to create an anonymous struct using your work or the string from f. they think they’re checking the interface’s value but they’re actually checking the interface itself for no type and 0 value. Golang - safe cast. Casting and Converting Objects and Primitive Types. 3k Golang : Extract part of string with regular expression +1. That being said, for your string to int cast, I would suggest you use the Int32. The name of the GridDB package for Golang is griddb_go. Here is a simple snippet how to convert a string into a boolean type in Golang. Sscanf scans the argument string, storing successive space-separated values into successive arguments as determined by the format. */ public interface Observer extends Configurable { /** * Record the request * * @param struct Struct information in a request. A named type is something like string or int32. In the previous post "A Closer Look at Golang From an Architect's Perspective," we offered a high level look at the Go programming language. cannot convert result (type interface {}) to type float64: need type assertion invalid operation: myInt += 5 (mismatched types interface {} and int) Functions and packages will at times return interface{} as a type because the type would be unpredicable or unknown to them. Let me give a recap for the beginners out there. Importing packages. The principal authors of golang, Robert Griesemer, Rob Pike, and Ken Thompson, have also been known to speak up on the forum from time to time. A slice is a structure of 3 fields. Slice is basically a pointer, with additional properties about the array. So far we have differentiated between the API for TCP and the API for UDP, using for example DialTCP and DialUDP returning a TCPConn and UDPConn respectively. not convert interface{} to int in Golang. It cannot be re-cast as a float64, because, well, "Unicorn" is a string. We can also name the return value by defining variables, here a variable total of integer type is defined in the function declaration for the value that the function returns. Importing packages. Grimoire is a database access layer inspired by Ecto. buffer prevents unnecessary string object from generating. type Person struct { FirstName string LastName string Age int } The type keyword introduces a new type. Golang - safe cast. How To Correctly Serialize JSON String In Golang. Pada kode di atas, disiapkan variabel data dengan tipe map[string]interface{} , yaitu sebuah koleksi dengan key bertipe string dan nilai bertipe interface kosong interface{}. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected] Interfaces in Go are a powerful language construct, which allow you to define and use objects of different types under a common umbrella interface. Since there is no implements keyword, all types implement at least zero methods, and satisfying an interface is done automatically, all types satisfy the empty interface. +13k Golang : Convert(cast) string to rune and back to string example +7. [TWTG p270] Detect and convert the type of an interface variable: type assertions¶. It provides a single sorting sequence only, i. It omits OOP idioms such as inheritance and polymorphism, in favor of composition and simple interfaces. Println("string length : ", len([]rune(testString))) It also gives you the same result. Slices and strings are out, unless your C code yields exactly the right memory layout for the respective slice/string headers, which is unlikely. You just to follow the interface and your program can be used for every infrastructure using the CNI for their network connectivity. So if any changes take place in the interface 1 and interface 2's methods it will reflect in interface 3. So what happened? The reason why Golang could not convert array/slice of a type to array/slice of an interface is clearly mentioned in the official FAQ. That's what I was trying to explain just above. Golang Typecasting Type conversion, type casting, and type coercion are different ways of changing an variable from one data type into another. This is slightly less efficient than some other solutions, since the fmt. var x interface{} = "abc" str := fmt. Multiple sources use the term duck typing when describing Go interfaces. Interfaces in Go are a powerful language construct, which allow you to define and use objects of different types under a common umbrella interface. So it will come as no surprise that it’s possible to create an Atlassian Connect for HipChat add-on with less than two hundred lines of commented code. Migrating a Chrome OS app to an extension for other platform users. As long as the Buffer has at least MinRead bytes beyond what is required to hold the contents of r, ReadFrom will not grow the underlying buffer. The reason why golang appears to have such wide adoption in such a short period of time is that it really does seem to contribute to helping devs get their shit done. It seems therefore the "encoding/json" package doesn´t recognize that element as an array. “TypeScript is a smart choice when writing a modern web- or JavaScript-based application. Get started with learning Golang in this tutorial. 10000 string 45. If you need to do things like that, check out the utilities in the standard library -- such as the strconv package!. The circle and rect struct types both implement the geometry interface so we can use instances of these structs as arguments to measure. By default, it will automatically detect the type that has a longer duration. "A string value is a (possibly empty) sequence of bytes. SockerRequest is the function to make a socket call to the endpoint. func Marshal(v interface{}) ([]byte, error) The function returns the JSON encoding form of v. For example, if you want to store a long value into a simple integer then you can type cast long to int. The fastest way to construct a string is direct cast from []byte to string, if you can make ensure the []byte does not go away or being modified. In this scenario, you can use type assertion:. A named type is something like string or int32. Golang - safe cast. The struct data type implements these interfaces to have method definitions for the method signature of the interfaces. a character constant, or a string literal. Multiple sources use the term duck typing when describing Go interfaces. It then calls the ToString(Int16, IFormatProvider) method to convert each element in an array of 16-bit integers to its equivalent string representation. Each string corresponds to a JSON property, and its mapped interface{} type corresponds to the value, which can be of any type. Go was designed at Google to improve programming productivity in an era of multicore, networked machines and large codebases. Golang tools can be used for a wide variety of projects and web applications. You may not be able to generate a pre-defined struct that you can subsequently unmarshal your JSON into. The Emails key has a value of interface{} type. Golang Custom Struct Tags Example. Go言語では、インターフェース型xから型Tについて、 x. Go is a statically typed programming language. ContextImpl cannot be cast to. buffer prevents unnecessary string object from generating. you check my other post on Convert String to Int type. Join(secret. 1 strconv FormatFloat function example strconv package has FormatFloat function is to convert the floating number to string with a given format and precision Here is a syntax of this function func FormatFloat(f float64, fmt byte, prec, bitSize int) string Arguments are. they think they’re checking the interface’s value but they’re actually checking the interface itself for no type and 0 value. However, a class or struct can implement multiple interfaces, but a class can inherit only a single class, abstract or not because the language doesn’t support. Every variable in golang has an associated type. The service receives a Go program, vets, compiles, links, and runs the program inside a sandbox, then returns the output. Type assertion s can be re-cast as a string, because its underlying type is a string. It provides a single sorting sequence only, i. We all know what Java is. Tools for Golang. One of the most ubiquitous interfaces is Stringer defined by the fmt package. /** The Observer interface. The type system is the most important feature of. In Golang, you'll often find yourself needing to convert from a byte slice to a string, or from a string to a byte slice. Massive amounts of working code are being written in golang, and that's good for the software industry as a whole. This allows us to pass strings to C code. Teknik casting pada interface disebut dengan type assertions. Golang switch between structs struct , go , interface , switch-statement In your example you are trying to pass the struct itself to the function rather than an instance of the struct. DynamoDB lets you offload the administrative burdens of operating and scaling a distributed database, so that you don't have to worry about hardware provisioning, setup. Sprint(x) to convert anything to a string the same way that fmt. (T) x is the variable whose type must be interface, and T is the type which you want to check. For example, if you want to store a long value into a simple integer then you can type cast long to int. interface is. The types Conn, PacketConn and Listener. This is the first part in our 2 part interface tutorial. When I first started programming in Go, my summary of it was, "The good things are great and the bad things are weird and I can live with them. Let me give a recap for the beginners out there. golang type cast (7) I'm new to Golang and I'm trying to get a value from a JSON and cast it to int but it doesn't work. Fruit, error)} On the next compile, Golang will notice that SomeHttpServer is now a FruitModeler. So we have one implementation of the interface. Is there any way to create an anonymous struct using your work or the string from f. The __typename field resolves to a String which lets you differentiate different data types from each other on the client. Java requires you to explicitly declare that a class "implements" an interface, but in Go you simply implement the methods defined by the interface. Java Comparable interface is used to order the objects of the user-defined class. I think it depends what kind of work you do, if it's primarily single page apps with a Go API, or a more traditional web app. go file, with string and int sets. Its syntax is as follows − type_name(expression) Example. ToStringMap casts an interface to a map[string]interface{} type. CONTENT About Golang Designing principles Environment setup Program Structure Tokens Data types Constants Operators Decision making Loop statements Function Scope Rules Arrays Structures Pointers Range Recursion Type casting. This Java interface tutorial explains how Java interfaces work, and how to use them. Every language in existance has its own set of oddities. We actually already saw instances of optional parameters with both the functional overloading and method overloading examples in figure 1 and figure 2. September 14, 2019 Unmarshaling postgresql jsonb query response string into golang nested struct. Cara casting objek interface sedikit unik, yaitu dengan menuliskan nama tipe tujuan dalam kurung, ditempatkan setelah nama interface dengan menggunakan notasi titik (seperti cara mengakses property, hanya saja ada tanda kurung nya). Sscanf scans the argument string, storing successive space-separated values into successive arguments as determined by the format. Creating a Simple Web Application using Golang Steffi Indrayani/135140631 Computer Science/Informatics School of Electrical Engineering and Informatics Institut Teknologi Bandung, Jl. Keeping it simple, let's define an add function like we did above, but we'll give it an Error() string method. 8, client-go code-generation is required. Cast is a library to convert between different go types in a consistent and easy way. type Printer interface { Print(string) } We just defined an interface named Printer that required an implementer to have a method named Print which takes a string parameter and returns nothing. 8k Golang : Random integer with rand. Extending, exploring, and discovering the vast Chrome functionality possibilities. Importing packages. var data map [string] interface {} err = json. Join(secret. 50 Shades of Go: Traps, Gotchas, and Common Mistakes for New Golang Devs 50 Shades of Go in Other Languages. data need to implement following functions. Example 3:. Interfaces are implemented implicitly in Go. [TWTG p270] Detect and convert the type of an interface variable: type assertions¶. not convert interface{} to int in Golang. Golang Oddity #1. Golang Interface. Go is a statically typed programming language. Sometimes, you might not have knowledge of the structure of the JSON string that you are reading. Go is a statically typed programming language. This tutorial shows how to build an image recognition service in Go using pre-trained TensorFlow Inception-V3 model. Dynamic programming vs memoization vs tabulation; Big O notation explained. In utf8 package, Golang provides a function to get the sentence length -> RuneCountInString which lets you to get the correct length of a string. ToStringMap casts an interface to a map[string]interface{} type. Ten Reasons Why I Don't Like Golang. 8k Golang : Random integer with rand. It only specifies what the object is supposed to do. Slice is basically a pointer, with additional properties about the array. Just in case you are wandering, yes we could have just created the function in a way such that it took both the headers string array and the headername string as arguments however creating a function that belongs to the “Headers” type makes a better design since this function conceptually can only be applied on the Headers string array. Often it is possible (through great refactoring and no net gain) to achieve what I want with interface somehow, but the resultant code is far less clear than generics would have been. July 26, 2016. MinRead is the minimum slice size passed to a Read call by Buffer. 100000 string 4. a character constant, or a string literal. It will not display the original text but byte value. id Abstract—Go Programming Language, which is often. The method is given a supply of nails and the board to drive the nail into. You just to follow the interface and your program can be used for every infrastructure using the CNI for their network connectivity. Instead of requiring a particular type, interfaces allow to specify that only some behaviour is. (T) asserts that the concrete value stored in x is of type T , and that x is not nil. Get started with learning Golang in this tutorial. Golang cast int, String In Any programming language, Anything user entered in text fields always considered as String and saved to Database as Integer. In the previous post "A Closer Look at Golang From an Architect's Perspective," we offered a high level look at the Go programming language. At Browserling we love to make developers' lives easier, so we created this collection of online string tools. So if any changes take place in the interface 1 and interface 2’s methods it will reflect in interface 3. go {3 4} 12 14 {5} 78. Teknik casting pada interface disebut dengan type assertions. This means that the library could have surfaced response data as a map of string => interface{} generics which would require the engineer to further cast into an int, string, another map of string => interface{}, etc. Tetapi jika kamu butuh injection dan operasi yang mengharuskan memiliki interface, maka kamu harus buat interfacenya. As long as the Buffer has at least MinRead bytes beyond what is required to hold the contents of r, ReadFrom will not grow the underlying buffer. More specifically, client-go requires that runtime. Golang Interface. A method set is a list of methods that a type must have in order to “implement” the interface. Slices and strings are out, unless your C code yields exactly the right memory layout for the respective slice/string headers, which is unlikely. Sprintf to convert an interface value to a string. 50 Shades of Go: Traps, Gotchas, and Common Mistakes for New Golang Devs 50 Shades of Go in Other Languages. Formatは、時間値をlayoutでフォーマットした文字列表現を返します。layoutは標準時の表現を示すことによってフォーマットを定義し、これを使って時刻をフォーマットします。. So if any changes take place in the interface 1 and interface 2's methods it will reflect in interface 3. Let me give a recap for the beginners out there. Pass Parameters by Reference in GolangA simple diary about a simple thing that I learned about Pass By Reference in Golangpass by reference on interface parameter in Golang Back to the college days, I remember there are 2 ways to pass a parameter to a function. Type Casting or Type Conversion in Golang Multiple Interfaces in Golang In Go language, the interface is a collection of method signatures and it is also a type means you can create a variable of an interface type. Golang printf cheat sheet. Optional parameters, from a programmer's point-of-view, is a parameter of a function or method. At Browserling we love to make developers' lives easier, so we created this collection of online string tools. To convert a string into a boolean use the ParseBool method. This interface is found in java. var myVar string = "hello" const myConst int = 5 The syntax is structured like so: KEYWORD NAME TYPE = VALUE "KEYWORD" is like a command that defines what you want to get. Then we can take an element (which will be again interface{} type). Here is a simple snippet how to convert a string into an int type in Golang. Go was born for the task. You will get great value from this course and, more importantly, you will have a great time learning the greatest programming language every made – The Go Programming Language – The fastest growing, highest paying programming language in America. Value to interface. When you use database like MySQL, MariaDB or SQLite, you can't use array fields unlike in Postgres or MongoDB. Amazon DynamoDB is a fully managed NoSQL database service that provides fast and predictable performance with seamless scalability. StringBuilder和StringBuffer都是专门. Strings are immutable: once created, it is impossible to change the contents of a string. It returns the boolean value represented by the string. First define the final structure you want the results to be in and Unmarshal the JSON into a blank interface{} type Person struct {FullName string Phone string} var i interface {} json. You may have slightly more verbose code setting up types etc, but you gain a ton productivity-wise from things like: * in. S -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. How to concatenate or add two strings? How to check if two strings are equal? How to get the index of first occurrence of a substring in a string?. For the least amount of programmer work, you can use fmt. Let’s talk a little about how we can use this property to make our Go code better, and to do that I’m going to take a brief digression into the Singleton pattern. Join(secret. Concatenate string literals (string enclosed in double quotes). Go was born for the task. Optional Parameters. One thing you discover quickly about Java is how finicky it is about the information it will handle. Interface methods are also like C++ virtual methods (or any Java method), and interface variables are also like instances of polymorphic base classes. Here is a working example: There are limitations to the struct field types you can use in this way. Cast does this intelligently when an obvious conversion is possible. post-7929950264021667177 2017-01-28T20:21:00. Or, you can also use type casting to cast this string into a rune array. ([]string), ", "). go, here https. */ public interface Observer extends Configurable { /** * Record the request * * @param struct Struct information in a request. They define how the data is stored in memory, what are the possible values that a variable of a particular data type can hold, and the operations that can be done on them. In some cases, we have to convert String variable into a Byte array format, for example, JCE encryption. Golang cast int, String In Any programming language, Anything user entered in text fields always considered as String and saved to Database as Integer. Cast provides simple functions to easily convert a number to a string, an interface into a bool, etc. func NewMapXmlSeq ¶ Uses. 510000e+01 string 45. If you use bytes. 10000 string 45. If you find a mistake or issue in this article, please fix it and submit a pull request on Github (must be signed in to your GitHub account). Ten Reasons Why I Don't Like Golang. CString is a cgo function that takes a go string and returns a pointer to a C char, ie: *C. Subscribe to our Newsletter. type Package struct { Dir string // directory containing package sources ImportPath string // import path of package in dir ImportComment string // path in import comment on packa. Get started with learning Golang in this tutorial. I think it depends what kind of work you do, if it’s primarily single page apps with a Go API, or a more traditional web app. 1 strconv FormatFloat function example strconv package has FormatFloat function is to convert the floating number to string with a given format and precision Here is a syntax of this function func FormatFloat(f float64, fmt byte, prec, bitSize int) string Arguments are. Or, you can also use type casting to cast this string into a rune array. To a large extent you can deal with this interface rather. Golang interfaces are a collection of methods. »Writing Custom Providers In Terraform, a Provider is the logical abstraction of an upstream API. To convert a string into a boolean use the ParseBool method. Cara casting objek interface sedikit unik, yaitu dengan menuliskan nama tipe tujuan dalam kurung, ditempatkan setelah nama interface dengan menggunakan notasi titik (seperti cara mengakses property, hanya saja ada tanda kurung nya). They can have properties but these need to be abstract or to provide accessor implementations. The types Conn, PacketConn and Listener. By the way, is it called casting when it comes to interfaces?. Golang - safe cast. They define how the data is stored in memory, what are the possible values that a variable of a particular data type can hold, and the operations that can be done on them. (T) This statement asserts that the interface value i holds the concrete type T and assigns the underlying T value to the variable t. Golang - safe cast. In utf8 package, Golang provides a function to get the sentence length -> RuneCountInString which lets you to get the correct length of a string. Hi there--thanks for providing this library! I'm in the process of upgrading from your now-deprecated go-msgpack library, where I was using the convenience methods Marshal and Unmarshal. Since I wanted to avoid casting interfaces to strings, I changed go-yaml's default behavior, and marshalled values to map[string]string. The Complete C# Masterclass will help you discover how to use C#, one of the most commonly used programming languages on earth. they think they’re checking the interface’s value but they’re actually checking the interface itself for no type and 0 value. cast does this intelligently when an obvious conversion is possible. This ordering is referred to as the class's natural ordering , and the class's compareTo method is referred to as its natural comparison method. 3k Golang : Extract part of string with regular expression +1. 1 strconv FormatFloat function example strconv package has FormatFloat function is to convert the floating number to string with a given format and precision Here is a syntax of this function func FormatFloat(f float64, fmt byte, prec, bitSize int) string Arguments are. " Rob Pike's blog post on string. Golang switch between structs struct , go , interface , switch-statement In your example you are trying to pass the struct itself to the function rather than an instance of the struct. You will get great value from this course and, more importantly, you will have a great time learning the greatest programming language every made – The Go Programming Language – The fastest growing, highest paying programming language in America. js and found out the discussion Which is preferred for a heavy user-based web app: Go, Node, Scala or Python ?. "NAME" is an alias to refer later, "TYPE" always goes on the right side. This class allows user to implement their own auditing solution. This allows us to modify strings in many ways. It appends strings to the slice values accessed by keys. Type assertions. What Are Interfaces In Go?. So if any changes take place in the interface 1 and interface 2's methods it will reflect in interface 3. In the following example, MySQL converts a string into an integer implicitly before doing calculation:. A Web-based Go IDE , do your development anytime, anywhere. At the end of this book you will have a program that allows you to generate every QR code possible using nothing but HTTP calls. (T) x is the variable whose type must be interface, and T is the type which you want to check. The most common numeric conversions are Atoi (string to int) and Itoa (int to string). Massive amounts of working code are being written in golang, and that's good for the software industry as a whole. (int) should work good. One of the most ubiquitous interfaces is Stringer defined by the fmt package. Recently I did strace to an http service app, actually did it without a reason but I found something interesting. Regardless of implementation, this method queries an object using the IID of the interface to which the caller wants a pointer. Golang switch between structs struct , go , interface , switch-statement In your example you are trying to pass the struct itself to the function rather than an instance of the struct. GOLANG ONLINE COURSE bestonlinecoursescoupon. Go interfaces were designed after protocols from the Smalltalk programming language.