拆分联接数据表R

Question

客观

在由DT1指定的每个i组中的给定键列中，将data.table（如DT2中的DT2）加入Date DT2[DT1, on = 'key']列。

我无法运行key，因为那是不正确的，因为Date列中的DT3列是重复的，但是在一个日期内是唯一的。

具有可行解决方案的可复制示例

split是我的预期输出。如果没有data.table -y的library(data.table) set.seed(1) DT1 <- data.table( Segment = sample(paste0('S', 1:10), 100, TRUE), Activity = sample(paste0('A', 1:5), 100, TRUE), Value = runif(100) ) dates <- seq(as.Date('2018-01-01'), as.Date('2018-11-30'), by = '1 day') DT2 <- data.table( Date = rep(dates, each = 5), Segment = sample(paste0('S', 1:10), 3340, TRUE), Total = runif(3340, 1, 2) ) rm(dates) # To ensure that each Date Segment combination is unique DT2 <- unique(DT2, by = c('Date', 'Segment')) iDT2 <- split(DT2, by = 'Date') iDT2 <- lapply( iDT2, function(x) { x[DT1, on = 'Segment', nomatch = 0] } ) DT3 <- rbindlist(iDT2, use.names = TRUE) 动作，有什么方法可以实现？

     ListView lViewSMS = (ListView) findViewById(R.id.listViewSMS);

            if(fetchInbox()!=null)
            {
                ArrayAdapter adapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, fetchInbox());
                lViewSMS.setAdapter(adapter);
            }
//put the above part in oncreateview()
        public ArrayList fetchInbox()
        {
            ArrayList sms = new ArrayList();

            Uri uriSms = Uri.parse("content://sms/inbox");
            Cursor cursor = getContentResolver().query(uriSms, new String[]{"_id", "address", "date", "body","" + "person"},null,null,null);

            cursor.moveToFirst();
            while  (cursor.moveToNext())
            {
                String match="is created";
                String address = cursor.getString(1);
                String body = cursor.getString(3);
               // String title = cursor.getString(3);
                String tdata=body;
       sms.add(""+""+body);






            }
            return sms;

        }

Answer 1

使用笛卡尔-1可以达到相同的结果：

answers = ["orange", "apple", "pear"]
if (answers.indexOf(userGuess) != -1) {
    console.log(userGuess + "is correct"); 
}

以下是证明：

merge