英文:
Parse formatted string in Golang
问题
我正在尝试使用Golang解析GNSS RINEX文件。
例如，这是VERSION行的RINEX规范：
+--------------------+------------------------------------------+------------+
|RINEX VERSION / TYPE| - 格式版本 (2.11) | F9.2,11X, |
| | - 文件类型 ('O' 表示观测数据) | A1,19X, |
| | - 卫星系统: 空白或 'G': GPS | A1,19X |
| | 'R': GLONASS | |
| | 'S': Geostationary | |
| | signal payload | |
| | 'E': Galileo | |
| | 'M': Mixed | |
+--------------------+------------------------------------------+------------+
RINEX文件中的每一行都有固定的宽度为80个ASCII字符 + "\n"。在这个例子中，前9个字符表示版本号（浮点数）。
在Python中，我可以使用：
struct.unpack("9s11s1s19s1s19s20s", line)
这将返回一个包含7个字符串的元组。
我是Go的新手，一直在尝试使用fmt.Sscanf来读取格式化文本：
func main() {
str := " 2.11 OBSERVATION DATA G (GPS) RINEX VERSION / TYPE\n"
var value float32
a, err := fmt.Sscanf(str,"%9.2f", &value)
fmt.Println(a)
fmt.Println(err)
fmt.Println(value)
}
返回：
0
bad verb %. for float32
0
Go中是否有任何包允许解析固定宽度的数据？
如果没有，编写类似于Python的struct的东西可能是一个好方法吗？
英文:
I'm trying to parse a GNSS RINEX file using Golang.
For example, here's the RINEX specification for the VERSION line:
+--------------------+------------------------------------------+------------+
|RINEX VERSION / TYPE| - Format version (2.11) | F9.2,11X, |
| | - File type ('O' for Observation Data) | A1,19X, |
| | - Satellite System: blank or 'G': GPS | A1,19X |
| | 'R': GLONASS | |
| | 'S': Geostationary | |
| | signal payload | |
| | 'E': Galileo | |
| | 'M': Mixed | |
+--------------------+------------------------------------------+------------+
Each line in a RINEX file has a fixed width of 80 ASCII characters + "\n". In this example the first 9 characters represent the version number (float).
In Python I might use:
struct.unpack("9s11s1s19s1s19s20s", line)
which would return a tuple with 7 strings.
I'm new to go and have been trying to use fmt.Sscanf for reading formatted text:
func main() {
str := " 2.11 OBSERVATION DATA G (GPS) RINEX VERSION / TYPE\n"
var value float32
a, err := fmt.Sscanf(str,"%9.2f", &value)
fmt.Println(a)
fmt.Println(err)
fmt.Println(value)
}
returns:
0
bad verb %. for float32
0
Is there any package in go that permits parsing of fixed width data?
And if not, what might be a good approach for writing something similar to Python's struct?
答案1
得分: 4
例如，
package main
import (
"errors"
"fmt"
"strconv"
"strings"
)
// http://gage14.upc.es/gLAB/HTML/LaunchHTML.html
// http://gage14.upc.es/gLAB/HTML/Observation_Rinex_v2.11.html
func parseVersionType(line string) (version float64, fileType, satellite, label string, err error) {
label = line[60:80]
if label != "RINEX VERSION / TYPE" {
err = errors.New("未知的头标签")
return
}
version, err = strconv.ParseFloat(strings.TrimSpace(line[0:9]), 64)
if err != nil {
return
}
fileType = line[20:21]
satellite = line[40:41]
return
}
func main() {
line := " 2.11 OBSERVATION DATA G (GPS) RINEX VERSION / TYPE\n"
version, fileType, satellite, label, err := parseVersionType(line)
fmt.Printf("%g %q %q %q %v\n", version, fileType, satellite, label, err)
}
输出：
2.11 "O" "G" "RINEX VERSION / TYPE" <nil>
英文:
For example,
package main
import (
"errors"
"fmt"
"strconv"
"strings"
)
// http://gage14.upc.es/gLAB/HTML/LaunchHTML.html
// http://gage14.upc.es/gLAB/HTML/Observation_Rinex_v2.11.html
func parseVersionType(line string) (version float64, fileType, satellite, label string, err error) {
label = line[60:80]
if label != "RINEX VERSION / TYPE" {
err = errors.New("Unknown header label")
return
}
version, err = strconv.ParseFloat(strings.TrimSpace(line[0:9]), 64)
if err != nil {
return
}
fileType = line[20:21]
satellite = line[40:41]
return
}
func main() {
line := " 2.11 OBSERVATION DATA G (GPS) RINEX VERSION / TYPE\n"
version, fileType, satellite, label, err := parseVersionType(line)
fmt.Printf("%g %q %q %q %v\n", version, fileType, satellite, label, err)
}
Output:
2.11 "O" "G" "RINEX VERSION / TYPE" <nil>
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