如何获取此可迭代枚举 (results.pose_landmarks.landmark) 的特定值之一（具有特定索引）？

Question

import cv2 #OpenCV is the library that we will be using for image processing
import mediapipe as mp #Mediapipe is the framework that will allow us to get our pose estimation
import time


mpDraw = mp.solutions.drawing_utils
mpPose = mp.solutions.pose

pose = mpPose.Pose()
#pose = mpPose.Pose(static_image_mode = False, upper_body_only = True) #ONLY UPPER_BODY_TRACKING

#cap = cv2.VideoCapture(0)
cap = cv2.VideoCapture('PoseVideos/1_girl_choreography.mp4')

pTime = 0 #previous time

while True:
    success, img = cap.read() #that will give it our image and then we can write the cv2.imshow()
    imgRGB = cv2.cvtColor(img, cv2.COLOR_BGR2RGB) #convert our image to RGB because Mediapipe use that format
    results = pose.process(imgRGB) #we are simply going to send this image to our model

    #print(enumerate(results.pose_landmarks.landmark)) #<enumerate object at 0x0000012312DD1A00>

    #so then we will check if it is detected or not
    if results.pose_landmarks:

        mpDraw.draw_landmarks(img, results.pose_landmarks, mpPose.POSE_CONNECTIONS) 

        for id, lm in enumerate(results.pose_landmarks.landmark):

            h, w, c = img.shape #get dimensions(h height, w width) and the c channel of image
            
            print(id)
            print(lm)

            cx, cy = int(lm.x * w), int(lm.y * h)

            cv2.circle(img, (cx, cy), 5, (255, 0, 0), cv2.FILLED)


    cTime = time.time()
    fps = 1 / (cTime - pTime)
    pTime = cTime

    cv2.putText(img, str(int(fps)), (70, 50), cv2.FONT_HERSHEY_PLAIN, 3, (255, 0, 0), 3)

    cv2.imshow("Image", img)
    cv2.waitKey(1)

我想做 for 做的事，但不是对 enumerate() 内的所有元素 (id) 做，而是只对 id = 25 做，因为在这种情况下它是唯一的点我感兴趣。

我需要在这条循环指令中更改什么，该指令用作此 enumerate(results.pose_landmarks.landmark):

的可迭代循环

如何输入 id[25] 和 lm[25]？

我尝试使用 itertools，但 ir 在这种情况下确实有效

import itertools

gen = (id, lm for id, lm in enumerate(results.pose_landmarks.landmark))
specific_id, specific_lm = 25,25 #index
print( next(itertools.islice(gen, specific_id, None)) )

Answer 1

你可以试试：

for id, lm in enumerate(results.pose_landmarks.landmark):
    if not id == 25:
        continue
    ...

不优雅，但完成工作。

Answer 2

可以直接访问results.pose_landmarks.landmark，无需枚举

lm = results.pose_landmarks.landmark[25]

results.pose_landmarks.landmark 是一个列表