sum varname, by(groupvar) ``` - weight():对数据进行加权汇总。 ``` sum varname [aweight=weightvar] ``` - fweights()、iweights()、pweights():分别使用频率权重、倒数权重和概率权重进行汇总。 ``` sum varname [fweight=weightvar] sum varname [iweight=weightvar] sum varname [pweight=...
写过Sql 的同学应该都知道 group by 是用来对数据进行分组的,一般与聚合函数一起使用,对分组后的数据进行聚合。虽然大家都在用,但是有些同学还是不太清楚 group by 的底层到底是如何实现分组并且最后进行聚合的。今天就讲讲 group by 的底层实现。 01 sql题目pandas解法(01):筛选、all、any常用技巧 有不...
by:指定按照哪些列进行分组,可以是单个列名或多个列名的列表。 axis:指定按照哪个轴进行分组,0表示按行分组,1表示按列分组。 level:指定按照哪个级别进行分组,用于多级索引的情况。 as_index:指定是否以分组的列作为索引,默认为True。 sort:指定是否对分组结果进行排序,默认为True。 示例代码: 示例代码: 输出结果:...
Twitter Google Share on Facebook zero-sum (redirected fromConstant sum) ze·ro-sum (zîr′ō-sŭm′, zē′rō-) adj. Of or relating to a situation in which a gain is offset by an equal loss:"Under the zero-sum budgeting system that governs federal spending, the money for spinal re...
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The CDR-GS is computed via an algorithm6 and the CDR-SB score is obtained by summing each of the domain box scores, with scores ranging from 0 to 18. Analyses Statistical analyses were conducted using both Stata version 9 (StataCorp, College Station, Texas) and SAS version 9.3 (SAS ...
for group 2, -stsum- gives me a median of 4 while -stci- gives me a median of 2. My understanding is that both should be the KM estimate of the median (which, from the data, should be 2). Is there a discrepancy in the way the survival times are computed by the two commands?
drop if group == 3 > . ranksum var1, by(group) > . restore > > Is there a smarter way to do this? > > lars > > > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla...
awe can rearrange the classroom schema, for example, group the students into six or change the desks into round shape from the square. And sometimes, we can try to let the students answer questions without stand up. It can somewhat relieve the tension of students. 我们可以重新整理教室图解,例...
the cdr-gs is computed via an algorithm and the cdr-sb score is obtained by summing each of the domain box scores, with scores ranging from 0 to 18. analyses statistical analyses were conducted using both stata version 9 (statacorp, college station, texas) and sas version 9.3 (sas ...