v0.0.0-...-926964d Latest Latest

This package is not in the latest version of its module.

Go to latest
Published: Feb 23, 2016 License: MIT, Apache-2.0 Imports: 8 Imported by: 0



Easy and safe casting from one type to another in Go

Don’t Panic! ... Cast

What is Cast?

Cast is a library to convert between different go types in a consistent and easy way.

Cast provides simple functions to easily convert a number to a string, an interface into a bool, etc. Cast does this intelligently when an obvious conversion is possible. It doesn’t make any attempts to guess what you meant, for example you can only convert a string to an int when it is a string representation of an int such as “8”. Cast was developed for use in Hugo, a website engine which uses YAML, TOML or JSON for meta data.

Why use Cast?

When working with dynamic data in Go you often need to cast or convert the data from one type into another. Cast goes beyond just using type assertion (though it uses that when possible) to provide a very straightforward and convenient library.

If you are working with interfaces to handle things like dynamic content you’ll need an easy way to convert an interface into a given type. This is the library for you.

If you are taking in data from YAML, TOML or JSON or other formats which lack full types, then Cast is the library for you.


Cast provides a handful of To_____ methods. These methods will always return the desired type. If input is provided that will not convert to that type, the 0 or nil value for that type will be returned.

Cast also provides identical methods To_____E. These return the same result as the To_____ methods, plus an additional error which tells you if it successfully converted. Using these methods you can tell the difference between when the input matched the zero value or when the conversion failed and the zero value was returned.

The following examples are merely a sample of what is available. Please review the code for a complete set.

Example ‘ToString’:
cast.ToString("mayonegg")         // "mayonegg"
cast.ToString(8)                  // "8"
cast.ToString(8.31)               // "8.31"
cast.ToString([]byte("one time")) // "one time"
cast.ToString(nil)                // ""

var foo interface{} = "one more time"
cast.ToString(foo)                // "one more time"
Example ‘ToInt’:
cast.ToInt(8)                  // 8
cast.ToInt(8.31)               // 8
cast.ToInt("8")                // 8
cast.ToInt(true)               // 1
cast.ToInt(false)              // 0

var eight interface{} = 8
cast.ToInt(eight)              // 8
cast.ToInt(nil)                // 0




This section is empty.


This section is empty.


func StringToDate

func StringToDate(s string) (time.Time, error)

func ToBool

func ToBool(i interface{}) bool

func ToBoolE

func ToBoolE(i interface{}) (bool, error)

func ToDuration

func ToDuration(i interface{}) time.Duration

func ToDurationE

func ToDurationE(i interface{}) (d time.Duration, err error)

func ToFloat64

func ToFloat64(i interface{}) float64

func ToFloat64E

func ToFloat64E(i interface{}) (float64, error)

func ToInt

func ToInt(i interface{}) int

func ToIntE

func ToIntE(i interface{}) (int, error)

func ToIntSlice

func ToIntSlice(i interface{}) []int

func ToIntSliceE

func ToIntSliceE(i interface{}) ([]int, error)

func ToSlice

func ToSlice(i interface{}) []interface{}

func ToSliceE

func ToSliceE(i interface{}) ([]interface{}, error)

func ToString

func ToString(i interface{}) string

func ToStringE

func ToStringE(i interface{}) (string, error)

func ToStringMap

func ToStringMap(i interface{}) map[string]interface{}

func ToStringMapBool

func ToStringMapBool(i interface{}) map[string]bool

func ToStringMapBoolE

func ToStringMapBoolE(i interface{}) (map[string]bool, error)

func ToStringMapE

func ToStringMapE(i interface{}) (map[string]interface{}, error)

func ToStringMapString

func ToStringMapString(i interface{}) map[string]string

func ToStringMapStringE

func ToStringMapStringE(i interface{}) (map[string]string, error)

func ToStringSlice

func ToStringSlice(i interface{}) []string

func ToStringSliceE

func ToStringSliceE(i interface{}) ([]string, error)

func ToTime

func ToTime(i interface{}) time.Time

func ToTimeE

func ToTimeE(i interface{}) (tim time.Time, err error)


This section is empty.

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL