頂点座標を空のnumpy.ndarrayに追加する操作。
よくやるのでメモ。
—(sample code)—–
import cv2
import numpy as np
## cat pol_int (x-y point list)
## -126 133
## -126 131
## -117 131
## -117 134
in_data = open("./plist")
lines = in_data.readlines()
arr = np.empty((0,2), int)
for i in range(len(lines)):
lines[i].strip()
jj = lines[i].split()
xx = int(jj[0])
yy = int(jj[1])
arr = np.append(arr, np.array([[xx, yy]]), axis=0)
i = i + 1
print(arr)
—(exec result)—–
[[-126 133]
[-126 131]
[-117 131]
[-117 134]]
—(memo)—-
initialize ndarray for x-y point list.
at first array is empty(no entry) and add_type is [x,y].
so initialize parameter is (0,2).
arr = np.empty((0,2), int)
if append for ndarray, append element must ndarray.
we use only 1 axis, so axis = 0(axis memo)
arr = np.append(arr, np.array([[xx, yy]]), axis=0)