用条件填充NA

Question

嗨，我有一个数据框

status       Value  
OFF           22
ON            34
OFF           NA
ON            NA
OFF           22
ON            12
ON            NA

当我的条件匹配时，我试图用之前的非NA值替换NA值，即IF NA找到状态为＆＃39; ON＆＃39;如果状态为ON，则替换为先前的非NA

df$required= ifelse(df$status='ON'& is.na(df$value),
                               na.locf(df$value,na.rm=F),df$value)

  

错误：意外＆＃39;，＆＃39;在＆＃34;

status       Value    required
OFF           22        22
ON            34        34
OFF           NA        NA
ON            NA        34
OFF           22        22
ON            12        12
ON            NA        12

任何修改都会被评估，谢谢