similar to: How to Read a Large CSV into a Database with R

Displaying 20 results from an estimated 1000 matches similar to: "How to Read a Large CSV into a Database with R"

2011 Apr 13
1
Decimals in R/SQL
Hello, When I am writing in sqldf or RSQLite I lose the decimals in my matrix. The only way I can get decimals is by multiplying by 1.00000, etc. I have tried manipulating the options, but it is only effective once I multiply by 1.0000. I appreciate any suggestions! Thanks! Example: z <- sqldf ("select ST, SUM(AGEP*PWGTP)*1.000000000/SUM(PWGTP)*1.00000000000000 as wgtage from ss09
2007 Sep 07
3
Delete query in sqldf?
Dear All, Is sqldf equipped with delete queries? I have tried delete queries but with no success. Thanks in advance, Paul
2009 Feb 20
2
importing data to SQLite database with sqldf
Hi all, I am attempting to learn SQL through sqldf... One task I am particularly interested in is merging separate (presumably large) files into a single table without loading these files into R as an intermediate step (by loading them into SQLite and merging them there). Taking a step back, I've considered these alternatives: 1) I know if I use straight SQLite commands I might use the
2010 May 20
1
sqldf: issues with natural joins
Hello, I'm having trouble discovering what's going wrong with my use of natural joins via sqldf. Following the instructions under 4i at http://code.google.com/p/sqldf/, which discusses creating indices to speed joins, I have been only unreliably able to get natural joins to work. For example, > Tid <- c('AES 01-01-02 10:58:00', 'AES 01-01-02 11:53:00', 'AES
2015 Jul 27
2
Error sql en función
Hola Carlos: Gracias por responder! Ayer caí en esta página al buscar el problema con google, pero no conseguir entender y implementar lo que sugiere. Sin entender nada, lo que hice fue: ======================== > library(MASS) > library (sqldf) # Per SQL > data(Aids2, package="MASS") > SQL_PROVA = function (XDADES, XWHE) + { + XDADES_SQL = sqldf ("select * from
2007 Aug 01
1
New R package sqldf
sqldf is an R package for running SQL select statements on one or more R data frames. It is optimized for convenience making it useful for ad hoc queries against R data frames. Given an SQL select statement whose tables are the names of R data frames it: - sets up the database (by default it transparently sets up an in memory SQLite database using RSQLite; however, MySQL via RMySQL, can be
2007 Aug 01
1
New R package sqldf
sqldf is an R package for running SQL select statements on one or more R data frames. It is optimized for convenience making it useful for ad hoc queries against R data frames. Given an SQL select statement whose tables are the names of R data frames it: - sets up the database (by default it transparently sets up an in memory SQLite database using RSQLite; however, MySQL via RMySQL, can be
2015 Jul 27
2
Error sql en función
Hola: No consigo que la función sqldf () funcione dentro de una función. Alguien puede echarme una mano. En resumen, el problema es que cuando lo ejecuto fuera de una función no tengo ningún problema: ========================== > # install.packages("sqldf") > library(MASS) > library (sqldf) > data(Aids2, package="MASS") > options(digits=3) > table
2011 Mar 09
2
SQLDF - Submitting Queries with R Objects as Columns
Fellow R programmers, I'd like to submit SQLDF statements with R objects as column names. For example, I want to assign "X" to "var1" (var1<-"X") and then refer to "var1" in the SQLDF statement. SQLDF needs to understand that when I reference "var1", it should look for "X" in the dataframe. This is necessary because my SQLDF
2017 Aug 11
2
Package sqldf in R and dates manipulation
Dear all, I recently read the book " R data preperation and manipulation using sqldf package" by Djoni Darmawikarta However, I have a problem with manipulation of dates using this package, I do not get the expected results. Do I need to install some packages to be able to subset the data by dates in sqldf? I am not getting Djoni Darmawikarta email address. Please see the practice
2008 Aug 28
3
drop unused levels in sqldf
Hi, sqldf is a fantastic package, but when the SELECT procedure runs unused levels remain in the output. I tried with the drop function, but without success. Do you have any suggestions? Thanx, Gianandrea data(iris) require(sqldf) base<-sqldf("select * from iris where Species <> 'setosa'") str(base) # Species with 3 levels! -- View this message in context:
2007 Nov 10
7
How to more efficently read in a big matrix
Dear list, I need to read in a big table with 487 columns and 238,305 rows (row names and column names are supplied). Is there a code to read in the table in a fast way? I tried the read.table() but it seems that it takes forever :( Thanks a lot! Best, Allen
2007 Nov 13
7
combine two dataframe
I have two data frame A and B adn want to cross them. A has format as: a1 a2 a3 1 2 3 2 3 1 1 3 2 ... B: b1 b2 1 2 2 1 ... the combine result shall be something like a1 a2 a3 b1 b2 1 2 3 1 2 1 2 3 2 1 2 3 1 1 2 2 3 1 2 1 1 3 2 1 2 1 3 2 2 1 .... is there a function able of doing this instead of loops? Thanks, Sun
2012 Jan 17
3
Using !is.na() in a HAVING clause in sqldf() XXXX
Hi everyone, I have the following: sqldf("select Premie,count(tpounds) N,avg(tpounds) Avg_Weight, stddev_samp(tpounds) StdDev from children group by Premie having !is.na(Premie)") sqldf() does not like the !is.na(Premie) specification. How does one exclude a "missing" group in an aggregated query using sqldf()? Thanks! Dan [[alternative HTML version deleted]]
2011 Apr 29
4
For loop and sqldf
Hi list, Can anyone tell my why the following does not work? Thanks a lot! Your help is very much appreciated. DF = data.frame(read.table(textConnection(" B C D E F G 8025 1995 0 4 1 2 8025 1997 1 1 3 4 8026 1995 0 7 0 0 8026 1996 1 2 3 0 8026 1997 1 2 3 1 8026 1998 6 0 0 4 8026 1999 3 7 0 3 8027 1997 1 2 3 9 8027 1998 1 2 3 1 8027 1999
2008 Dec 14
1
error with sqldf v0-1.4
I'm getting an error message when using the new version of sqldf, > library(sqldf) > str(kdv) 'data.frame': 71 obs. of 3 variables: $ dpss: num 0.117 0.144 0.164 0.166 0.165 ... $ npdp: num 0.1264 0.0325 0.0109 0.0033 0.0055 ... $ logk: num 1.12 1.29 1.41 1.41 1.42 ... > test=sqldf("select * from kdv") Error in get("fun", env = this, inherits =
2012 Jul 11
2
Passing Multiple Variable Into SQLDF Statement as parameters of function
Hey guys, So I'm working with a project where I manage a database within R, and I'm developing a script/function that will automatically run my queries in R depending on the date parameters passed in. The problem is that when I create variables for the dates, and use those variables in my sqldf statements, R says that there is no such column in the dataframe (which is true!). My question
2013 Jul 16
4
Sqldf y codificación \u00b0 para el grado
Buenos días: Creo un data.frame del siguiente modo: d<-data.frame(a=c("112.45º", "23,56º"), b=c("112.45\u00b0", "23.56\u00b0")) > d         a       b 1 112.45º 112.45° 2  23,56º  23.56° Como podéis ver, para la primera columna vuelco el grado directamente, y para la segunda utilizo \u00b0, que es lo que debo perseguir. Ahora obtengo d2 del
2017 Sep 11
4
Case statement in sqldf
Hi all, I am trying to create a new variable called Fiscal Year (FY) using case expression in sqldf and I am getting a null FY , see the code below . Please advise me as to how I can do this mutation. library(zoo) library(lubridate) library(stringr) library(RH2) library(sqldf) cr$ReportDate = as.Date(cr$ReportDate, format ='%Y-%m-%d') > cr2 = sqldf(" select
2014 Mar 12
2
Frecuencia absoluta acumulada por individuo y por
Por si tienes especial interés en utilizar sqldf: todos <- sqldf( "select distinct a.ID,b.YEAR from dt a , dt b;") suma <- sqldf( "select ID,YEAR,sum(CANTIDAD) as CANTIDAD from dt group by ID,YEAR;") todos <- sqldf( "select a.ID,a.YEAR, CANTIDAD from todos a left join suma b on a.ID = b.ID and a.YEAR = b.YEAR group by a.ID,a.YEAR;") todos$CANTIDAD =