02-variables

README

02-variables

Based on https://golang.org/doc/tutorial/getting-started#call and following on from previous tutorial..

What did we learn?

• import can use a block syntax ( .... ) to import multiple modules instead of typing import on each line.
• ... this also applies to var definitions! (and probably other definitions I'm guessing)
• Go supports package level variable scopes, and local block scopes - and defining the same variable in a local scope is called shadowing (it "shadows" the original)
• lowerCase variables defined at the package level are scoped to the package, whereas UpperCase variables are exported/globally visable outside the package
• Casting a variable to another type is pretty much same as most languages, i.e. a = type(b) e.g. a := int(b)
• fmt.Printf() is pretty funky, it has %v (value) and %T (type) if you wanted to debug easily
• Go is pretty strict on using variables! If you don't use a variable it will complain at compile time.
• Uninitialised variables have a "zero" value, i.e. 0 for numeric types, "" (empty string) for strings, and false for booleans
• string creation with double-quotes "" are internally stored as bytes (uint8) and encoded as UTF-8, so 1 character can be 1-3 bytes
• single-quotes '' mean something different - you are indicating its a rune, a single int32 value, e.g. '明'
• ... so "明" would have a len() of 3 as its actually stored as 3x bytes (uint8), whereas '明' would have a len() of 1 as its stored as 1x int32

Output from this code:

Don't communicate by sharing memory, share memory by communicating.
(float32) 1.1
(int) 88
(float32) 88.000000
(string) this is a string
defaults: bool=false, int=0, string=
 string size: hello 明 (string of length 9)
as byte size: [104 101 108 108 111 32 230 152 142] ([]uint8 of length 9)
as rune size: [104 101 108 108 111 32 26126] ([]int32 of length 7)