英文:
Golang: How do I convert command line arguments to integers?
问题
我想编写一个脚本，对用户提供的参数进行插入排序，就像这样：
$ insertionSort 1 2 110 39
我希望它返回：
[1 2 39 110]
但实际返回的是：
[1 110 2 39]
我认为这是因为os.Args数组中的元素是字符串。所以，我的问题是如何将os.Args数组的元素转换为整数？这是我的代码：
package main
import (
"fmt"
"os"
"reflect"
"strconv"
)
func main() {
A := os.Args[1:]
for i := 0; i <= len(A); i++ {
strconv.Atoi(A[i])
fmt.Println(reflect.TypeOf(A[i]))
}
for j := 1; j < len(A); j++ {
key := A[j]
i := j - 1
for i >= 0 && A[i] > key {
A[i+1] = A[i]
i = i - 1
A[i+1] = key
}
}
fmt.Println(A)
}
顺便提一下，当我将
strconv.Atoi(A[i])
替换为
A[i] = strconv.Atoi(A[i])
时，我得到以下错误：
./insertionSort.go:14: multiple-value strconv.Atoi() in single-value context
谢谢你的时间！
英文:
I want to make a script that does an insertion sort on the arguments provided by the user, like this:
$ insertionSort 1 2 110 39
I expect it to return:
[1 2 39 110]
But it returns:
[1 110 2 39]
I think it's because the elements in the os.Args array are strings. So, my question is how do I convert the elements of the os.Args array into integers? Here's my code:
package main
import (
"fmt"
"os"
"reflect"
"strconv"
)
func main() {
A := os.Args[1:]
for i := 0; i <= len(A); i++ {
strconv.Atoi(A[i])
fmt.Println(reflect.TypeOf(A[i]))
}
for j := 1; j < len(A); j++ {
key := A[j]
i := j - 1
for i >= 0 && A[i] > key {
A[i+1] = A[i]
i = i - 1
A[i+1] = key
}
}
fmt.Println(A)
}
As a heads up, when I substitute
strconv.Atoi(A[i])
For
A[i] = strconv.Atoi(A[i])
I get the following error:
./insertionSort.go:14: multiple-value strconv.Atoi() in single-value context
Thank you for your time!
答案1
得分: 10
Atoi 函数从字符串中解析出一个数字和一个错误（或者是nil）。
- ParseInt 函数将字符串 s 解释为给定进制（2 到 36）的值 i，并返回该值。如果 base == 0，则进制由字符串的前缀决定：对于 "0x"，进制为 16；对于 "0"，进制为 8；否则进制为 10。
- bitSize 参数指定结果必须适应的整数类型。bitSize 值为 0、8、16、32 和 64 分别对应 int、int8、int16、int32 和 int64。
- *ParseInt 返回的错误具有具体类型 NumError，并且包含 err.Num = s。如果 s 为空或包含无效的数字，则 err.Err = ErrSyntax，返回值为 0； 如果 s 对应的值无法用给定大小的有符号整数表示，则 err.Err = ErrRange，返回值为适当 bitSize 和符号的最大幅度整数。
你需要做的是：
var err error
nums := make([]int, len(A))
for i := 0; i < len(A); i++ {
if nums[i], err = strconv.Atoi(A[i]); err != nil {
panic(err)
}
fmt.Println(nums[i])
}
工作示例：http://play.golang.org/p/XDBA_PSZml
英文:
Atoi returns the number and an error (or nil) from
> ParseInt interprets a string s in the given base (2 to 36) and returns the corresponding value i. If base == 0, the base is implied by the string's prefix: base 16 for "0x", base 8 for "0", and base 10 otherwise.
> The bitSize argument specifies the integer type that the result must fit into. Bit sizes 0, 8, 16, 32, and 64 correspond to int, int8, int16, int32, and int64.
> *The errors that ParseInt returns have concrete type NumError and include err.Num = s. If s is empty or contains invalid digits, err.Err = ErrSyntax and the returned value is 0; if the value corresponding to s cannot be represented by a signed integer of the given size, err.Err = ErrRange and the returned value is the maximum magnitude integer of the appropriate bitSize and sign.
You need to do :
var err error
nums := make([]int, len(A))
for i := 0; i < len(A); i++ {
if nums[i], err = strconv.Atoi(A[i]); err != nil {
panic(err)
}
fmt.Println(nums[i])
}
Working example : http://play.golang.org/p/XDBA_PSZml
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