小编Lui*_*.G.的帖子

我在这里看到:如何在DataFrame中将时间戳转换为日期格式？转换datetype中的时间戳的方法,但至少对我来说,它不起作用.

这是我尝试过的

# Create dataframe
df_test = spark.createDataFrame([('20170809',), ('20171007',)], ['date',])

# Convert to timestamp
df_test2 = df_test.withColumn('timestamp',func.when((df_test.date.isNull() | (df_test.date == '')) , '0')\
.otherwise(func.unix_timestamp(df_test.date,'yyyyMMdd')))\

# Convert timestamp to date again
df_test2.withColumn('date_again', df_test2['timestamp'].cast(stypes.DateType())).show()

但是这会在date_again列中返回null:

+--------+----------+----------+
|    date| timestamp|date_again|
+--------+----------+----------+
|20170809|1502229600|      null|
|20171007|1507327200|      null|
+--------+----------+----------+

什么失败了？

我需要从excel文档创建通知,我正在使用Java和Apache POI.这是我的代码:

    //Get path with JFileChooser
    public static String LeeRuta(){
        JFileChooser chooser = new JFileChooser();
        chooser.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
        chooser.showDialog(chooser, "Seleccionar");
        File f =chooser.getSelectedFile();
        File camino = f.getAbsoluteFile();
        String ruta = camino.getAbsolutePath();
        return ruta;
    }

  //main
  public static void main(String args[]) {
    String ruta=LeeRuta();

    /* Don't know if neccesary, but it didn't works with or without it
    InputStream inp;
    try {
        inp = new FileInputStream(ruta);
    } catch (FileNotFoundException ex) {
        Logger.getLogger(PruebaExcel.class.getName()).log(Level.SEVERE, null, ex);
    }
    */

    Workbook exceldoc = null;

    // Opening file
      try …

我正在从复数中清除一个txt,并用fscanf逐字逐句读取txt.问题是当我用fwrite编写干净的txt时,它会将所有内容写在一起.

我试图定义一个字符并仅指定一个空格,但在写入时也添加了"òwD".任何人都知道如何只添加''？

char espa[0];       
espa[0]=' ';
f2 = fopen("clean.txt", "w");   

       while(!feof(f))
       {
            char reader[100];
            int aux;
            fscanf (f, "%s", reader);

            if feof(f){
                printf("%s ", reader);
                printf("\n\nFin del fichero\n");
            }
            else
                if(cadena[(strlen(reader)-1)]=='s'){
                    for(aux=0;aux<(strlen(reader)-1);aux++){
                        printf("%c", reader[aux]);
                    }
                    fwrite(cadena, (strlen(reader))-1, 1, f2); //Add clean word
                }
                else{
                    printf(" %s ", reader);
                    fwrite(reader, (strlen(reader)), 1, f2); //Add normal word
                }

            fwrite(espa, (strlen(espa)), 1, f2); //Here I try to add the space
       }
       fclose(f);  
       fclose(f2);
}