imageloc字典作为全局变量，然后添加到全局的列表中，每次for循环都会将最新的元素改变之前for循环添加的元素。而imageloc字典作为局部变量，则不会影响。

import numpy as np
originaljson = [{"joints_vis": [1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1],"joints": [[804.0,711.0],[816.0,510.0],[908.0,438.0],[1040.0,454.0],[906.0,528.0],[883.0,707.0],[974.0,446.0],[985.0,253.0],[982.7591,235.9694],[962.2409,80.0306],[869.0,214.0],[798.0,340.0],[902.0,253.0],[1067.0,253.0],[1167.0,353.0],[1142.0,478.0]],"image": "005808361.jpg","scale": 4.718488,"center": [966.0,340.0]},{"joints_vis": [1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1],"joints": [[317.0,412.0],[318.0,299.0],[290.0,274.0],[353.0,275.0],[403.0,299.0],[394.0,409.0],[322.0,275.0],[327.0,172.0],[329.9945,162.1051],[347.0055,105.8949],[296.0,135.0],[281.0,208.0],[296.0,167.0],[358.0,177.0],[387.0,236.0],[392.0,167.0]],"image": "052475642.jpg","scale": 1.761835,"center": [316.0,220.0]},{"joints_vis": [0,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1],"joints": [[-1.0,-1.0],[1033.0,649.0],[1072.0,474.0],[973.0,496.0],[961.0,650.0],[-1.0,-1.0],[1023.0,485.0],[1031.0,295.0],[1026.998,281.6248],[997.002,181.3752],[988.0,294.0],[1018.0,317.0],[1070.0,290.0],[991.0,300.0],[912.0,345.0],[842.0,330.0]],"image": "052475643.jpg","scale": 3.139233,"center": [1030.0,396.0]},{"joints_vis": [0,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1],"joints": [[-1.0,-1.0],[804.0,659.0],[786.0,498.0],[868.0,509.0],[860.0,693.0],[-1.0,-1.0],[827.0,504.0],[840.0,314.0],[838.9079,308.9326],[816.0921,203.0674],[698.0,264.0],[740.0,297.0],[790.0,300.0],[889.0,328.0],[915.0,452.0],[906.0,553.0]],"image": "004645041.jpg","scale": 3.248877,"center": [809.0,403.0]}
]newjson = []# imageloc = {}
for i in range(len(originaljson)):imageloc = {}box = []imagename = originaljson[i]["image"].split('.')[0]box.append(1)box.append(2)box.append(3)box.append(4)imageloc[imagename] = boxnewjson.append(imageloc)