英文:
strconv.ParseInt fails if number starts with 0
问题
我目前遇到了在Go语言中解析以0开头的一些数字的问题。
fmt.Println(strconv.ParseInt("0491031", 0, 64))
> 0 strconv.ParseInt: 解析"0491031"时出现无效语法
GoPlayground链接：https://go.dev/play/p/TAv7IEoyI8I
我认为这是由于一些基数转换错误导致的，但我不知道如何修复它。
我在解析一个超过5GB的CSV文件时遇到了这个错误，如果你需要更多细节，请告诉我。
[这个错误是由GoCSV库引起的，该库不允许为要解析的数字指定基数。]
英文:
I'm currently having issues parsing some numbers starting with 0 in Go.
fmt.Println(strconv.ParseInt("0491031", 0, 64))
> 0 strconv.ParseInt: parsing "0491031": invalid syntax
GoPlayground: https://go.dev/play/p/TAv7IEoyI8I
I think this is due to some base conversion error, but I don't have ideas about how to fix it.
I'm getting this error parsing a 5GB+ csv file with gocsv, if you need more details.
[This error was caused by the GoCSV library that doesn't allow to specify a base for the numbers you're going to parse.]
答案1
得分: 5
> 如果基数参数为0，则基数由字符串的前缀隐含确定（如果存在符号）：对于“0b”，基数为2；对于“0”或“0o”，基数为8；对于“0x”，基数为16；否则，基数为10。此外，仅对于基数为0的参数，根据Go语法中整数字面量的定义，允许使用下划线字符。
你将base参数设置为0，因此将从字符串值中推断出要解析的基数。由于字符串以'0'开头，后面跟着一个非'0'的字符，因此你的数字被解释为八进制（8进制）数字，而数字9在八进制中是无效的。
请注意，以下代码可以正常工作：
fmt.Println(strconv.ParseInt("0431031", 0, 64))
输出结果为（在Go Playground上尝试）：
143897 <nil>
（八进制431031等于十进制143897。）
如果你的输入是十进制，请将base设置为10：
fmt.Println(strconv.ParseInt("0491031", 10, 64))
然后输出结果为（在Go Playground上尝试）：
491031 <nil>
英文:
Quoting from strconv.ParseInt()
> If the base argument is 0, the true base is implied by the string's prefix following the sign (if present): 2 for "0b", 8 for "0" or "0o", 16 for "0x", and 10 otherwise. Also, for argument base 0 only, underscore characters are permitted as defined by the Go syntax for integer literals.
You are passing 0 for base, so the base to parse in will be inferred from the string value, and since it starts with a '0' followed by a non '0', your number is interpreted as an octal (8) number, and the digit 9 is invalid there.
Note that this would work:
fmt.Println(strconv.ParseInt("0431031", 0, 64))
And output (try it on the Go Playground):
143897 <nil>
(Octal 431031 equals 143897 decimal.)
If your input is in base 10, pass 10 for base:
fmt.Println(strconv.ParseInt("0491031", 10, 64))
Then output will be (try it on the Go Playground):
491031 <nil>
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论