我有一个719mb的CSV文件，看起来像:from,to,dep,freq,arr,code,mode(headerrow)RGBOXFD,RGBPADTON,127,0,27,99999,2RGBOXFD,RGBPADTON,127,0,33,99999,2RGBOXFD,RGBRDLEY,127,0,1425,99999,2RGBOXFD,RGBCHOLSEY,127,0,52,99999,2RGBOXFD,RGBMDNHEAD,127,0,91,99999,2RGBDIDCOTP,RGBPADTON,127,0,46,99999,2RGBDIDCOTP,RGBPADTON,127

我有一个719mb的CSV文件，看起来像:from,to,dep,freq,arr,code,mode(headerrow)RGBOXFD,RGBPADTON,127,0,27,99999,2RGBOXFD,RGBPADTON,127,0,33,99999,2RGBOXFD,RGBRDLEY,127,0,1425,99999,2RGBOXFD,RGBCHOLSEY,127,0,52,99999,2RGBOXFD,RGBMDNHEAD,127,0,91,99999,2RGBDIDCOTP,RGBPADTON,127,0,46,99999,2RGBDIDCOTP,RGBPADTON,127