npyio
provides read/write access to numpy data files.
Is done via go get
:
$> go get github.com/sbinet/npyio
Is available on godoc
npyio-ls
is a command using github.com/sbinet/npyio
(located under
github.com/sbinet/npyio/cmd/npyio-ls
) to display the content of a (list of)
NumPy
data file(s).
$> npyio-ls testdata/data_float64_2x3_?order.npy
================================================================================
file: testdata/data_float64_2x3_corder.npy
npy-header: Header{Major:1, Minor:0, Descr:{Type:<f8, Fortran:false, Shape:[2 3]}}
data = [0 1 2 3 4 5]
================================================================================
file: testdata/data_float64_2x3_forder.npy
npy-header: Header{Major:1, Minor:0, Descr:{Type:<f8, Fortran:true, Shape:[2 3]}}
data = [0 1 2 3 4 5]
$> npyio-ls testdata/data_float64_2x3x4_corder.npy
================================================================================
file: testdata/data_float64_2x3x4_corder.npy
npy-header: Header{Major:1, Minor:0, Descr:{Type:<f8, Fortran:false, Shape:[2 3 4]}}
data = [0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23]
npyio-ls
automatically detects .npz
archive files and inspects them too:
$> npyio-ls testdata/data_float64_corder.npz
================================================================================
file: testdata/data_float64_corder.npz
entry: arr1.npy
npy-header: Header{Major:1, Minor:0, Descr:{Type:<f8, Fortran:false, Shape:[6 1]}}
data = [0 1 2 3 4 5]
entry: arr0.npy
npy-header: Header{Major:1, Minor:0, Descr:{Type:<f8, Fortran:false, Shape:[2 3]}}
data = [0 1 2 3 4 5]
Consider a .npy
file created with the following python
code:
>>> import numpy as np
>>> arr = np.arange(6, dtype="float64").reshape(2,3)
>>> f = open("data.npy", "w")
>>> np.save(f, arr)
>>> f.close()
The (float64) data array can be loaded into a (float64) mat.Matrix
by the following code:
package main
import (
"fmt"
"log"
"os"
"github.com/sbinet/npyio"
"gonum.org/v1/gonum/mat"
)
func main() {
f, err := os.Open(os.Args[1])
if err != nil {
log.Fatal(err)
}
defer f.Close()
r, err := npyio.NewReader(f)
if err != nil {
log.Fatal(err)
}
fmt.Printf("npy-header: %v\n", r.Header)
shape := r.Header.Descr.Shape
raw := make([]float64, shape[0]*shape[1])
err = r.Read(&raw)
if err != nil {
log.Fatal(err)
}
m := mat.NewDense(shape[0], shape[1], raw)
fmt.Printf("data = %v\n", mat.Formatted(m, mat.Prefix(" ")))
}
$> my-binary data.npy
npy-header: Header{Major:1, Minor:0, Descr:{Type:<i8, Fortran:false, Shape:[2 3]}}
data = ⎡0 1 2⎤
⎣3 4 5⎦
Alternatively, one can use the convenience function npyio.Read
:
package main
import (
"fmt"
"log"
"os"
"github.com/sbinet/npyio"
)
func main() {
f, err := os.Open(os.Args[1])
if err != nil {
log.Fatal(err)
}
defer f.Close()
var m []float64
err = npyio.Read(f, &m)
if err != nil {
log.Fatal(err)
}
fmt.Printf("data = %v\n", m)
}
$> my-binary ./data.npy
data = [0 1 2 3 4 5]
package main
import (
"log"
"os"
"github.com/sbinet/npyio"
)
func main() {
f, err := os.Create("data.npy")
if err != nil {
log.Fatal(err)
}
defer f.Close()
m := []float64{0, 1, 2, 3, 4, 5}
err = npyio.Write(f, m)
if err != nil {
log.Fatalf("error writing to file: %v\n", err)
}
err = f.Close()
if err != nil {
log.Fatalf("error closing file: %v\n", err)
}
}
package main
import (
"log"
"os"
"fmt"
"github.com/sbinet/npyio"
"gonum.org/v1/gonum/mat"
)
func main() {
f, err := os.Open(os.Args[1])
if err != nil {
log.Fatal(err)
}
defer f.Close()
npzData,npyData,err:= npyio.Load(f)
if err != nil {
log.Fatal(err)
}
if npyData!=nil {
//npy file
fmt.Printf("data = %v\n", npyData.Value)
return
}
for fileName, data := range npzData {
fmt.Printf("file = %s ", fileName)
fmt.Printf("data = %v\n", data.Value)
}
}
package main
import (
"log"
"os"
"fmt"
"github.com/sbinet/npyio"
"gonum.org/v1/gonum/mat"
)
func main() {
f, err := os.Open(os.Args[1])
if err != nil {
log.Fatal(err)
}
defer f.Close()
data := make(map[string]interface{})
data["a"] = []float64{1,2,3,4,5,6}
data["b"] = []float32{3,4,5,6,7}
data["c"] = mat.NewDense(3,2,[]float64{1,3,5,7,9,11})
err = npyio.SaveNPZ(f,data)
if err != nil {
log.Fatal(err)
}
}