How do I summarize the aggregation in a function by passing a list of conditions and values?
# This works fine:
x <- data.frame(cond1 = sample(letters[1:3], 500, replace=TRUE) ,
cond2 = sam
Tag: column name
When I don’t want to use aggregate, I should use Pivot to convert SQL Server 2008 row value to column names?
I am trying to master the manipulation of table data into a more visually attractive output format. This may be part of the problem, because what I want may be for a separate reporting software. <
How to use custom column names (using “by”) Data.Table without using “: =”?
I know I can do this
a <- dt[,sum(x), by=y ] I can do this too
dt[,z:=sum(x), by=y] # this would modify dt But I don’t know why I can’t do this:
a <- dt[,z=sum(x), by=y] < p>How t
PowerDesigner table name, column name size write conversion
From Open Source China: https://my.oschina.net/chwencong/blog/52650 PowerDesigner table name, column name case conversion Collection Car water code farmers Posted in 5
SQLite – How to get the primary key column name for a given table?
All I know is the name of the table and the id value of the query I want to execute, but I don’t know what id is called in the table. You can use the answer to a quite similar question to find t