yaml.scanner.ScannerError: while scanning a directive - yaml

Question

I use PyYAML to read a file, python code is:
with open('demo.yml') as f:
dataMap = yaml.load(f)
demo.yml:
%YAML:1.0
my_svm: !!opencv-ml-svm
svm_type: C_SVC
kernel: { type:LINEAR }
C: 1.
Then error is:
yaml.scanner.ScannerError: while scanning a directive
in "demo.yml", line 1, column 1
expected alphabetic or numeric character, but found ':'
in "demo.yml", line 1, column 6
Someone help me?

Answer 1

The directive should be %YAML 1.0 (with no colon). You also will need a "document start" (---) to separate your directives from the document. E.g.:
%YAML 1.0
---
my_svm: !!opencv-ml-svm
svm_type: C_SVC
kernel: { type: LINEAR }
C: 1.

Answer 2

you can modify the yaml file created by opencv 3.0
file1 from opencv:
1 %YAML:1.0
2 my_svm: !!opencv-ml-svm
3 svm_type: C_SVC
4 kernel: { type:LINEAR }
5 C: 1.
6 ...
file2:
1 my_svm: opencv-ml-svm
2 svm_type: C_SVC
3 kernel: { type: LINEAR }
4 C: 1.
5 ...
file1 -> file2:
delete line 1
delete "!!opencv-ml-svm"
add space after "type:" in line 4
then you can use yaml.load(filename) to load your data.

Answer 3

This worked for me:
from cv2 import cv
import numpy as np
filepath = "test.yml"
matrixA = np.array( cv.Load(filepath, cv.CreateMemStorage(), "matrixA") )
matrixB = np.array( cv.Load(filepath, cv.CreateMemStorage(), "matrixB") )
print "matrixA:", matrixA
print "matrixB:", matrixB
As seen in:
http://xudongai.blogspot.jp/2013/08/how-to-use-python-to-load-opencv-yml.html