How to do one-liner if else statement

Question

Can I write a simple if-else statement with variable assignment in go  golang  as I would do in php  For example   var      a  gt   b     a   b   Currently I have to use the following  var c int if a  gt  b       c   a   else       c   b    Sorry I cannot remember the name if this control statement and I couldn t find the info in-site or through google search

User · Answer

You can use a closure for this   func doif b bool  f1  f2 func          switch      case b          f1       case  b             f2            func dothis     fmt Println  Condition is true      func dothat     fmt Println  Condition is false      func main          condition    true     doif condition  func     dothis      func     dothat          The only gripe I have with the closure syntax in Go is there is no alias for the default zero parameter zero return function  then it would be much nicer  think like how you declare map  array and slice literals with just a type name    Or even the shorter version  as a commenter just suggested   func doif b bool  f1  f2 func          switch      case b          f1       case  b             f2            func dothis     fmt Println  Condition is true      func dothat     fmt Println  Condition is false      func main          condition    true     doif condition  dothis  dothat      You would still need to use a closure if you needed to give parameters to the functions  This could be obviated in the case of passing methods rather than just functions I think  where the parameters are the struct associated with the methods

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One possible way to do this in just one line by using a map  simple I am checking whether a  gt  b if it is true I am assigning c to a otherwise b  c    map bool int true  a  false  b  a  gt  b    However  this looks amazing but in some cases it might NOT be the perfect solution because of evaluation order  For example  if I am checking whether an object is not nil get some property out of it  look at the following code snippet which will panic in case of myObj equals nil  type MyStruct struct      field1 string    field2 string     var myObj  MyStruct myObj   nil   myField    map bool string true  myObj field1  false   empty    myObj    nil    Because map will be created and built first before evaluating the condition so in case of myObj   nil this will simply panic    Not to forget to mention that you can still do the conditions in just one simple line  check the following    var c int     if a  gt  b   c   a   else   c   b

User · Answer

I often use the following   c    b if a  gt  b       c   a     basically the same as  Not a Golfer s but using type inference

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Thanks for pointing toward the correct answer  I have just checked the Golang FAQ  duh  and it clearly states  this is not available in the language   Does Go have the    operator  There is no ternary form in Go  You may use the following to achieve the same result  if expr       n   trueVal   else       n   falseVal     additional info found that might be of interest on the  subject   Rosetta Code for Conditional Structures in Go Ternary Operator in Go experiment from this guy

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Like user2680100 said  in Golang you can have the structure  if  lt statement gt    lt evaluation gt         statements        else        statements         This is useful to shortcut some expressions that need error checking  or another kind of boolean checking  like   var number int64 if v    os Getenv  quot NUMBER quot    v     quot  quot       if number  err   strconv ParseInt v  10  64   err    nil          os Exit 42         else       os Exit 1     With this you can achieve something like  in C   Sprite  buffer   get sprite  quot foo png quot    Sprite  foo sprite    buffer    0    buffer   donut sprite  But is evident that this sugar in Golang have to be used with moderation  for me  personally  I like to use this sugar with max of one level of nesting  like   var number int64 if v    os Getenv  quot NUMBER quot    v     quot  quot        number  err   strconv ParseInt v  10  64      if err    nil           os Exit 42          else       os Exit 1     You can also implement ternary expressions with functions like func Ternary b bool  a interface    b interface             but i don t like this approach  looks like a creation of a exception case in syntax  and creation of this  quot features quot   in my personal opinion  reduce the focus on that matters  that is algorithm and readability  but  the most important thing that makes me don t go for this way is that fact that this can bring a kind of overhead  and bring more cycles to in your program execution

User · Answer

As the others mentioned  Go does not support ternary one-liners  However  I wrote a utility function that could help you achieve what you want      IfThenElse evaluates a condition  if true returns the first parameter otherwise the second func IfThenElse condition bool  a interface    b interface    interface         if condition           return a           return b     Here are some test cases to show how you can use it  func TestIfThenElse t  testing T        assert Equal t  IfThenElse 1    1   Yes   false    Yes       assert Equal t  IfThenElse 1    1  nil  1   1      assert Equal t  IfThenElse 1  lt  2  nil   No    nil      For fun  I wrote more useful utility functions such as   IfThen 1    1   Yes       Yes  IfThen 1    1   Woo      nil IfThen 1  lt  2   Less       Less   IfThenElse 1    1   Yes   false      Yes  IfThenElse 1    1  nil  1           1 IfThenElse 1  lt  2  nil   No          nil  DefaultIfNil nil  nil      nil DefaultIfNil nil              DefaultIfNil  A    B        A  DefaultIfNil true   B      true DefaultIfNil 1  false      1  FirstNonNil nil  nil                    nil FirstNonNil nil                            FirstNonNil  A    B                      A  FirstNonNil true   B                    true FirstNonNil 1  false                    1 FirstNonNil nil  nil  nil  10           10 FirstNonNil nil  nil  nil  nil  nil     nil FirstNonNil                             nil   If you would like to use any of these  you can find them here https   github com shomali11 util

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As the comments mentioned  Go doesn t support ternary one liners  The shortest form I can think of is this  var c int if c   b  a  gt  b       c   a    But please don t do that  it s not worth it and will only confuse people who read your code

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Sometimes  I try to use anonymous function to achieve defining and assigning happen at the same line  like below    a  b   4  8  c    func   int       if a  gt b         return a            return b          https   play golang org p rMjqytMYeQ0

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A very similar construction is available in the language    if  lt statement gt    lt evaluation gt        statements        else       statements              i e   if path err    os Executable    err    nil      log Println err    else      log Println path

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Ternary   operator alternatives   golang if else one line You can   t write a short one-line conditional in Go language   there is no ternary conditional operator  Read more about if  else of Golang

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Use lambda function instead of ternary operator  Example 1  to give the max int  package main  func main          println  func a b int  int  if a gt b  return a  else  return b    1 2        Example 2  Suppose you have this must err error  function to handle errors and you want to use it when a condition isn t fulfilled   enjoy at https   play golang com p COXyo0qIslP   package main  import        errors       log       os        must is a little helper to handle errors  If passed error    nil  it simply panics  func must err error        if err    nil           log Println err          panic err           func main          tmpDir    os TempDir          Make sure os TempDir didn t return empty string        reusing my favourite  must  helper        Isn t that kinda creepy now though      must func   error           var err error         if len tmpDir   gt  0               err   nil           else               err   errors New  os TempDir is empty                     return err             Don t forget that empty parentheses to invoke the lambda      println  We happy with   tmpDir

[if-statement] How to do one-liner if else statement?

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