Is there a foreach loop in Go

Question

Is there a foreach construct in the Go language  Can I iterate over a slice or array using a for

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Go has a foreach-like syntax  It supports arrays slices  maps and channels   Iterate over array or slice      index and value for i  v    range slice        index only for i    range slice        value only for    v    range slice      Iterate over a map      key and value for key  value    range theMap        key only for key    range theMap        value only for    value    range theMap      Iterate over a channel   for v    range theChan      Iterating over a channel is equivalent to receiving from a channel until it is closed   for       v  ok     lt -theChan     if  ok           break

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I have jus implement this library https   github com jose78 go-collection  This is an example about how to use the Foreach loop  package main  import        quot fmt quot       col  quot github com jose78 go-collection collections quot     type user struct       name string     age  int     id   int    func main         newList    col ListType user  quot Alvaro quot   6  1   user  quot Sofia quot   3  2       newList   append newList  user  quot Mon quot   0  3        newList Foreach simpleLoop           if err    newList Foreach simpleLoopWithError   err    nil          fmt Printf  quot This error  gt  gt  gt   v  lt  lt  lt  was produced quot   err              var simpleLoop col FnForeachList   func mapper interface    index int        fmt Printf  quot  d - item  v n quot   index  mapper      var simpleLoopWithError col FnForeachList   func mapper interface    index int        if index  gt  1          panic fmt Sprintf  quot Error produced with index     d n quot   index             fmt Printf  quot  d - item  v n quot   index  mapper     The result of this execution should be  0 - item  Alvaro 6 1  1 - item  Sofia 3 2  2 - item  Mon 0 3  0 - item  Alvaro 6 1  1 - item  Sofia 3 2  Recovered in f Error produced with index    2  ERROR  Error produced with index    2 This error  gt  gt  gt  Error produced with index    2   lt  lt  lt  was produced  Try this code in playGrounD

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You can in fact use range without referencing it s return values by using for range against your type   arr    make   uint8  5  i j    0 0 for range arr       fmt Println  Array Loop  i      i      for range  bytes        fmt Println  String Loop  j      j       https   play golang org p XHrHLbJMEd

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Yes  Range    The range form of the for loop iterates over a slice or map   When ranging over a slice  two values are returned for each iteration  The first is the index  and the second is a copy of the element at that index   Example    package main  import  fmt   var pow     int 1  2  4  8  16  32  64  128   func main         for i  v    range pow           fmt Printf  2   d    d n   i  v             for i    range pow           pow i    1  lt  lt  uint i        2  i           for    value    range pow           fmt Printf   d n   value             You can skip the index or value by assigning to    If you only want the index  drop the   value entirely

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Following is the example code for how to use foreach in golang  package main  import        fmt     func main          arrayOne     3 string  Apple    Mango    Banana        for index element    range arrayOne           fmt Println index          fmt Println element                         This is a running example https   play golang org p LXptmH4X 0

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The following example shows how to use the range operator in a for loop to implement a foreach loop   func PrintXml  out io Writer  value interface    error       var data   byte     var err error      for    action    range   func             func      data  err   xml MarshalIndent value                       func         err   out Write   byte xml Header              func         err   out Write data             func         err   out Write   byte   n                 action            if err    nil               return err                     return nil      The example iterates over an array of functions to unify the error handling for the functions  A complete example is at Google  s playground   PS  it shows also that hanging braces are a bad idea for the readability of code  Hint  the for condition ends just before the action   call  Obvious  isn t it

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This may be obvious  but you can inline the array like so   package main  import        fmt     func main         for    element    range  3 string  a    b    c             fmt Print element            outputs   abc   https   play golang org p gkKgF3y5nmt

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https   golang org ref spec For range     A  for  statement with a  range  clause iterates through all entries   of an array  slice  string or map  or values received on a channel    For each entry it assigns iteration values to corresponding iteration   variables and then executes the block    As an example   for index  element    range someSlice          index is the index where we are        element is the element from someSlice for where we are     If you don t care about the index  you can use     for    element    range someSlice          element is the element from someSlice for where we are     The underscore     is the blank identifier  an anonymous placeholder

[go] Is there a foreach loop in Go?

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