我试图得到一个窗口函数返回，并得到一个特定日期的前一行，不太确定是出了什么问题，但它是给我的前一行，而不是指定的日期行。为了计算这一点，我取当前行的日期，并找到当前星期一与该周的关系，如下所示

def previous_day(date, dayOfWeek):
        return date_sub(next_day(date, "monday"), 7)
    spark_df = spark_df.withColumn("last_monday", previous_day(spark_df['calendarday'], "monday"))

然后我计算当前日期和最近的前一个星期一之间的差值

d = F.datediff(spark_df['calendarday'], spark_df['last_monday'])
    spark_df = spark_df.withColumn("daysSinceMonday",d)

从我的dayssincemonday值可以看出每行的值是正确的。接下来，我想创建一个窗口，并选择它的第一行，但范围他们的d值，我设置，但由于某种原因，它不起作用。

days = lambda i: i * 86400 
    w = (Window.partitionBy(column_list).orderBy(col('calendarday').cast("timestamp").cast("long")).rangeBetween(-days(d), 0))
    spark_df = spark_df.withColumn('PreviousYearUnique', first("indexCP").over(w))

    Starting Data Frame
    ## +---+-----------+-----------+--------+       
    ## | id|calendarday|last_monday| indexCP|
    ## +---+-----------+-----------+--------+
    ## |  1|2015-01-05 | 2015-01-05|  0.0076|
    ## |  1|2015-01-06 | 2015-01-05|  0.0026|
    ## |  1|2015-01-07 | 2015-01-05|  0.0016|
    ## |  1|2015-01-08 | 2015-01-05|  0.0006|
    ## |  2|2015-01-09 | 2015-01-05|  0.0012|
    ## |  2|2015-01-10 | 2015-01-05|  0.0014|
    ## |  1|2015-01-12 | 2015-01-12|  0.0026|
    ## |  1|2015-01-13 | 2015-01-12|  0.0086|
    ## |  1|2015-01-14 | 2015-01-12|  0.0046|
    ## |  1|2015-01-15 | 2015-01-12|  0.0021|
    ## |  2|2015-01-16 | 2015-01-12|  0.0042|
    ## |  2|2015-01-17 | 2015-01-12|  0.0099|
    ## +---+-----------+-----------+--------+

    New Data Frame Adding Previous last_mondays row indexCP as PreviousYearUnique
    ## +---+-----------+-----------+--------+--------------------+       
    ## | id|calendarday|last_monday| indexCP| PreviousYearUnique |
    ## +---+-----------+-----------+--------+--------------------+
    ## |  1|2015-01-05 | 2015-01-05|  0.0076|              0.0076|
    ## |  1|2015-01-06 | 2015-01-05|  0.0026|              0.0076|
    ## |  1|2015-01-07 | 2015-01-05|  0.0016|              0.0076|
    ## |  1|2015-01-08 | 2015-01-05|  0.0006|              0.0076|
    ## |  2|2015-01-09 | 2015-01-05|  0.0012|              0.0076|
    ## |  2|2015-01-10 | 2015-01-05|  0.0014|              0.0076|
    ## |  1|2015-01-12 | 2015-01-12|  0.0026|              0.0026|
    ## |  1|2015-01-13 | 2015-01-12|  0.0086|              0.0026|
    ## |  1|2015-01-14 | 2015-01-12|  0.0046|              0.0026|
    ## |  1|2015-01-15 | 2015-01-12|  0.0021|              0.0026|
    ## |  2|2015-01-16 | 2015-01-12|  0.0042|              0.0026|
    ## |  2|2015-01-17 | 2015-01-12|  0.0099|              0.0026|
    ## +---+-----------+-----------+--------+--------------------+

有什么问题吗？