Let me count the ways...
R supplies a number of different ways. Here is sample using basic R and some other packages. Youprobably will need to install the packages ( ?install.packages) to run any but aggregate().
mydata <- structure(list(Name = structure(c(4L, 4L, 4L, 4L, 2L, 2L, 2L,
3L, 3L, 3L, 3L, 3L, 3L, 1L, 1L, 1L), .Label = c("Jacques K",
"Rahul D ", "Ricky P ", "Sachin T "), class = "factor"), Score = c(25L,
53L, 57L, 34L, 38L, 31L, 53L, 7L, 45L, 27L, 17L, 86L, 48L, 23L,
86L, 32L)), .Names = c("Name", "Score"), class = "data.frame", row.names = c(NA,
-16L))
# R basic
aggregate(Score ~ Name, mean, data = mydata)
library(reshape2)
dcast(mydata, Name ~ . , mean)
library(plyr)
ddply(mydata, .(Name), summarize, Mean = mean(Score))
library(data.table)
DT <- data.table(mydata)
DT[, mean(Score),by=Name]
John Kane
Kingston ON Canada
-----Original Message-----
From: guruappa at gmail.com
Sent: Thu, 26 Jul 2012 01:59:37 -0700 (PDT)
To: r-help at r-project.org
Subject: [R] Passing arguments to SQL Query in R
Hello all,
I am a newbie at R, with some experience in PERL.
I have a database table that contains the following data:
Name | Score
======= | =====
Sachin T | 25
Sachin T | 53
Sachin T | 57
Sachin T | 34
Rahul D | 38
Rahul D | 31
Rahul D | 53
Ricky P | 7
Ricky P | 45
Ricky P | 27
Ricky P | 17
Ricky P | 86
Ricky P | 48
Jacques K | 23
Jacques K | 86
Jacques K | 32
I want the summary data as below:
Name | Avg Score
Jacques K|47.00
Rahul D|40.67
Ricky P|38.33
Sachin T|42.25
Currently, I am trying to pass the name of the person as an argument in a
sql query by breaking the query into parts, and then concatenating the
query
string. Of course, the scheme is not working.
I want a query as below:
SELECT NAME, SCORE FROM PLAYER_SCORE_TBL where NAME = ?
Then I can pass the parameters like we do in PERL.
If there is an alternative to the whole scheme, that would be wonderful.
a
way that would just take the whole table, and provide pivot table like
solution.
Thanks in advance,
Guruppa Padsali.
--
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