Saving images using Opencv in python

Question

Is there a better way to rewrite this part in python. It doesnot have to be shorter as long as its much better. thanks in advance

count = 1
while count < 10:
 _, pho = webcam.read()
 gr = cv2.cvtColor(im, cv2.COLOR_BGR2GRAY)
 images = face_cascade.detectMultiScale(gr, 1.3, 4)
 for (x,y,w,h) in faces: 
 cv2.rectangle(pho,(x,y),(x+w,y+h),(0,255,0),2)
 fa = gray[y:y + h, x:x + w]
 e_size = cv2.resize(fa, (100, 100))
 cv2.imwrite('%s/%s.JPEG' % (folder,count), e_size)
 count += 1
 cv2.imshow('OpenCV', pho)
 key = cv2.waitKey(20) 

Answer 1

A very simple change that replaces the while loop with a for loop (I don't know much about OpenCV, so I can't help too much there):

for count in range(1, 10):
 _, pho = webcam.read()
 gr = cv2.cvtColor(im, cv2.COLOR_BGR2GRAY)
 images = face_cascade.detectMultiScale(gr, 1.3, 4)
 for (x,y,w,h) in faces: 
 cv2.rectangle(pho,(x,y),(x+w,y+h),(0,255,0),2)
 fa = gray[y:y + h, x:x + w]
 e_size = cv2.resize(fa, (100, 100))
 cv2.imwrite('%s/%s.JPEG' % (folder,count), e_size)
 cv2.imshow('OpenCV', pho)
 key = cv2.waitKey(20) 

Additionally, in Python 3 especially, the % string formatting syntax is out-of-favor/deprecated -- use the {} and .format syntax instead:

cv2.imwrite('%s/%s.JPEG' % (folder,count), e_size)

becomes

cv2.imwrite('{!s}/{!s}.JPEG'.format(folder, count), e_size)