用“For循环”填充矩阵需要太长时间

I'm trying to create a data frame that is about 1,000,000 x 5 by using a for-loop, but it's been 5+ hours and I don't think it will finish very soon. I'm using the rjson library to read in the data from a large json file. Can someone help me with filling up this data frame in a faster way?I'm trying to create a data frame that is about