您只需要将NA替换为NULL：
require(RJSONIO)json_file <- '[{"name":"Doe, John","group":"Red","age (y)":24,"height (cm)":182,"wieght (kg)":74.8,"score":null}, {"name":"Doe, Jane","group":"Green","age (y)":30,"height (cm)":170,"wieght (kg)":70.1,"score":500}, {"name":"Smith, Joan","group":"Yellow","age (y)":41,"height (cm)":169,"wieght (kg)":60,"score":null}, {"name":"Brown, Sam","group":"Green","age (y)":22,"height (cm)":183,"wieght (kg)":75,"score":865}, {"name":"Jones, Larry","group":"Green","age (y)":31,"height (cm)":178,"wieght (kg)":83.9,"score":221}, {"name":"Murray, Seth","group":"Red","age (y)":35,"height (cm)":172,"wieght (kg)":76.2,"score":413}, {"name":"Doe, Jane","group":"Yellow","age (y)":22,"height (cm)":164,"wieght (kg)":68,"score":902}]'json_file <- fromJSON(json_file)json_file <- lapply(json_file, function(x) { x[sapply(x, is.null)] <- NA unlist(x)})一旦每个元素都有一个非空值，就可以调用
rbind而不会出现错误：
do.call("rbind", json_file) namegroup age (y) height (cm) wieght (kg) score[1,] "Doe, John" "Red" "24" "182" "74.8" NA [2,] "Doe, Jane" "Green" "30" "170" "70.1" "500"[3,] "Smith, Joan" "Yellow" "41" "169" "60" NA [4,] "Brown, Sam" "Green" "22" "183" "75" "865"[5,] "Jones, Larry" "Green" "31" "178" "83.9" "221"[6,] "Murray, Seth" "Red" "35" "172" "76.2" "413"[7,] "Doe, Jane" "Yellow" "22" "164" "68" "902"
