C#/java Programmer to Go/golang Programmer's Notes (Day 05)

-----------------------------------------Error usage (Exception handling)

// Grammar   (normal error) " Errors "  int, err error) {    = errors. New (" custom error message ")}

-----------------------------------------Panic use (Exception handling)

// Grammar   (Fatal error) Panic (" custom error message "//  Direct Interrupt Application //  e.g. array out of bounds, NULL pointer exception is implemented inside go Panic function

-----------------------------------------Recover use (Exception handling)

// Grammar      (Recovery error) // recover must be placed behind the defer to use defer func () {    //  recover ()    if err: = Recover (); Err! = Nil {    //  produced a panic anomaly         FMT. Println (Recover ())    }} ()    //  Note: The defer method executes after completion, () calls the anonymous function by default

-----------------------------------------string Processing

//   base operation://Contains/join/index/repeat/repalce/split/trim/fiel   DS//  conversion://  append/format/parse

-----------------------------------------regexp Regular Expressions

Import"RegExp"Func Main () {buf:="0.2 456 asdx 1.233 7.8.99 Aloong 6.66"Reg:= RegExp. Mustcompile (' \d+\.\d ')ifReg = =Nil {//... error        return} Result:= Reg. Findallstring (BUF,-1)    //Print Resultresult = Reg. Findadllstringsubmatch (BUF,-1)}

-----------------------------------------JSON usage (struct to JSON)

Import ("Encoding/json"    "FMT")//convert JSON based on struct bodyType ITstruct{ Companystring                /*//Struct_tag use, Syntax: Company string ' JSON: ' Company ' '///two encoding company string ' JSON: '-' '//-means that the field does not output to the screen IsOK BOOL ' JSON: ', string '//Turn string*/subjects []stringIsOKBOOLPrice Float64}func Main () {s:= it{"it", []string{"C #","Java","python","Go"},false,666.66}        //buf, err: = json. Marshal (s)BUF, err: = json. Marshal (s),""," ")//format Encoding    ifErr! =Nil {//Print Err        return} fmt. Println (string(BUF))}

Use of-----------------------------------------JSON (map to JSON)

Func Main () {    m:= Make (map[string]interface1//  interface{} Universal data Type    m["company""loongsoft "        result, err: "" " " )    //  println (String (Result))}

-----------------------------------------JSON usage (JSON to struct)

Func Main () {    var  tmp IT    json. UNMARSHLL ([]byte(jsonvalue), &tmp)    //  print tmp}

-----------------------------------------IO Operation files

// Create/newfile/open/openfile // .. documents