Convert str[0] & str[:1] to int

Key point: The bottom layer of string is a byte array, so string can also be sliced.

First let’s take a look at a demo

str := "121"
fmt.Println(str[0]) //string底层是一个byte数组，因此string也可以进行切片处理

Output results

49

explain:

1. First, let’s take a look at the data type after string slicing.

fmt.Printf("type=%T",str[0])

type=uint8

fmt.Printf("type=%T",str[:1])

type=string

2.When the byte array is output, the corresponding ASCII will be output.

decimal	graphics
49	1

(1) str[0] is converted into the corresponding int

1.strInt := int(str[0])

(2) str[:1] is converted into the corresponding int 

2.strInt := int([]byte(str[:1]))