Re: [R] RSQLite to input dataframe

[Amy Milano]

Dear sir,

When I was going through RSQLite.pdf file, I was just wondering if at all I 
will understand this. But you have explained it in such a simple and lucid 
manner, that although I am yet to go thoroughly through the mail, I am filled 
with confidence that yes now i can do it and I am going to circulate your mail 
through my office so that all will be benefited. 

Thanks a lot sir once again. Must say that was "The Guidnace".

Regards

Amy

  

--- On Tue, 1/4/11, Michael Bedward  wrote:

From: Michael Bedward 
Subject: Re: [R] RSQLite to input dataframe
To: "Amy Milano" , "Rhelp" 
Date: Tuesday, January 4, 2011, 11:32 AM

Hi Amy,

I'm not sure if I understand your question correctly so let me know if
the following is off track.

Starting with your example, here is how to create a data.frame and
write it to a new table in a new database file...

my.data = data.frame(X = c("US", "UK", "Canada", "Australia",
"Newzealand"), Y = c(52, 36, 74, 10, 98))

drv <- dbDriver("SQLite")
con <- dbConnect(drv, "myfilename.db")
dbWriteTable(con, "sometablename", my.data)

To verify that the table is now in the file...

dbListTables(con)

To check the fields in the table (should match the colnames in your
data.frame)...

dbListFields(con, "sometablename")

To read the whole table into the workspace as a new data.frame

my.data.copy <- dbReadTable(con, "sometablename")

If you have data in a CSV file, and the contents are small enough to
read in one go, you would use the read.csv function to read the
contents of the file into a data.frame and then use dbWriteTable to
transfer this to your database.

Hope this helps,

Michael


On 4 January 2011 21:43, Amy Milano  wrote:
> Dear r helpers,
>
> At first, I apologize for raising a query which seems to be a stupid 
> interpretation on my part. I am trying to learn SQLite.
>
>
>
> Following is an example given in the RSQLite.zip file (Page # 4)
>
> drv <- dbDriver("SQLite")
> tfile <- tempfile()
> con <- dbConnect(drv, dbname = tfile)
> data(USArrests)
> dbWriteTable(con, "arrests", USArrests)
>
>
> On the similar line I am trying to read my data.
>
> Suppose I have a dataframe as given below.
>
> DF = data.frame(X = c("US", "UK", "Canada", "Australia", "Newzealand"), Y = 
> c(52, 36, 74, 10, 98))
>
> drv <- dbDriver("SQLite")
> tfile <- tempfile()
> con <- dbConnect(drv, dbname = tfile)
> data(DF)
> dbWriteTable(con, ..., ...) # Didn't know what to write here.
>
> I understand I have raised a query in a stupid manner. I need to understand 
> is there any way I can use SQLite to read
>  dataframe or for that matter any csv file say e.g. 'DF.csv'.
>
> Please enlighten me.
>
> Amy
>
>
>
>        [[alternative HTML version deleted]]
>
> __
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



  
[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

[R] RSQLite to input dataframe

[Amy Milano]

Dear r helpers,

At first, I apologize for raising a query which seems to be a stupid 
interpretation on my part. I am trying to learn SQLite.



Following is an example given in the RSQLite.zip file (Page # 4)

drv <- dbDriver("SQLite")
tfile <- tempfile()
con <- dbConnect(drv, dbname = tfile)
data(USArrests)
dbWriteTable(con, "arrests", USArrests)


On the similar line I am trying to read my data.

Suppose I have a dataframe as given below.

DF = data.frame(X = c("US", "UK", "Canada", "Australia", "Newzealand"), Y = 
c(52, 36, 74, 10, 98))

drv <- dbDriver("SQLite")
tfile <- tempfile()
con <- dbConnect(drv, dbname = tfile)
data(DF)
dbWriteTable(con, ..., ...) # Didn't know what to write here.

I understand I have raised a query in a stupid manner. I need to understand is 
there any way I can use SQLite to read
 dataframe or for that matter any csv file say e.g. 'DF.csv'.

Please enlighten me.

Amy


  
[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

[R] Fw: Re: Default Working directory on windows 7?

[Amy Milano]

Suppose your working "R" directory is

C:\My Working Directory

I hope now that you have installed the R, you must be having "R ICON" on your 
desktop.

Right click on this icon, then click on Properties. Once that box is opened, 
you will find a tab called "Start in". There within the " " type C:\My Working 
Directory. So it should look like "C:\My Working Directory"

Then click on OK.

So whenever you execute "R" henceforth, this will remain your working directory 
till the time you change it using above process.


I hope I have addressed your query. Of course others may be having different 
efficient methods to do it.

HTH

Amy



--- On Tue, 1/4/11, W Eryk Wolski  wrote:

From: W Eryk Wolski 
Subject: [R] Default Working directory on windows 7?
To: r-help@r-project.org
Date: Tuesday, January 4, 2011, 9:35 AM

Hi,

Just installed R on a new Windows 7 machine (as admin).


I feel quite uncomfortable knowing that the default WD when starting R is:

> getwd()
[1] "C:/Windows/system32"



I guess I did something wrong when installing R... How to change R's
default working directory?

regards

Eryk

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.









  


  
[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Re: [R] Changing column names

[Amy Milano]

Please read - http://127.0.0.1:24408/library/base/html/colnames.html

I am trying to give an example. I am not a programmer and I am sure the R 
stalwarts will have better ways to do it.

# Suppose

df1 = read.csv('result.csv')

where (say e.g.) result.csv is as follows

result.csv

 var1   var2 
1  25 45 
2  80    132 
3 135 11 

country = c("US", "Canada")

colnames(df1) <- country

HTH

Amy


--- On Fri, 12/31/10, Vincy Pyne  wrote:

From: Vincy Pyne 
Subject: [R] Changing column names
To: r-help@r-project.org
Date: Friday, December 31, 2010, 6:07 AM

Dear R helpers

Wish you all a very Happy and Prosperous New Year 2011.

I have following query.

country = c("US", "France", "UK", "NewZealand", "Germany", "Austria", "Italy", 
"Canada")

Through some other R process, the result.csv file is generated as

result.csv

 var1   var2  var3  var4    var5    var6   var7   var8
1  25 45    29    92 108 105 65 56
2  80    132    83    38  38  11 47 74
3 135 11    74    56  74  74 74 29

                  
I need the country names to be column heads i.e. I need an output like

> result_new
    US    France     UK   NewZealand  Germany  Austria      Italy 
Canada
1   25          45      29              92     108    
105    65         56
2   80        132  83  38       38      
11    47         74
3  135 11  74  56       74      
74    74         29
                  

The number of countries i.e. length(country) matches with total number of 
variables (i.e. no of columns in 'result.csv').                  
                                    
One way of doing this is to use country names as column names while writing the 
'result.csv' file. 

write.csv(data.frame(US = ..., France = ...), 'result.csv', 
row.names = FALSE)


However, the problem is I don't know in what order the country names will 
appear and also there could be addition or deletion of some country names. 
Also, if there are say 150 country names, the above way (i.e. writing.csv) of 
defining the column names is not practical. 

Basically I want to change the column heads after the 'result.csv' is generated.

Kindly guide.

Regards

Vincy




    [[alternative HTML version deleted]]


-Inline Attachment Follows-

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.



  
[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Re: [R] Writing a single output file

[Amy Milano]

Dear sir,

At the outset I sincerely apologize for reverting back bit late as I was out of 
office. I thank you for your guidance extended by you in response to my earlier 
mail regarding "Writing a single output file" where I was trying to read 
multiple output files and create a single output date.frame. However, I think 
things are not working as I am mentioning below -


# Your code

setwd('/temp')
fileNames <- list.files(pattern = "file.*.csv")

input <- do.call(rbind, lapply(fileNames, function(.name)
{
.data <- read.table(.name, header = TRUE, as.is = TRUE)
.data$file <- .name
.data
}))


# This produces following output containing only two columns and moreover date 
and yield_rates are clubbed together.


 
 date.yield_rate  file
1   12/23/10,5.25 file1.csv
2   12/22/10,5.19 file1.csv
3   12/23/10,4.16 file2.csv
4   12/22/10,4.59 file2.csv
5   12/23/10,6.15 file3.csv
6   12/22/10,6.41 file3.csv
7   12/23/10,8.15 file4.csv
8   12/22/10,8.68 file4.csv


# and NOT the kind of output given below where date and yield_rates are 
different.

> input
    date  yield_rate  file
1 12/23/2010   5.25 file1.csv
2 12/22/2010   5.19 file1.csv
3 12/23/2010   5.25 file2.csv
4 12/22/2010   5.19 file2.csv
5 12/23/2010   5.25 file3.csv
6
 12/22/2010   5.19 file3.csv
7 12/23/2010   5.25 file4.csv
8 12/22/2010   5.19 file4.csv

So when I tried following code to produce the required result, it throws me an 
error.

require(reshape)

in.melt <- melt(input, measure = 'yield_rate')
> in.melt <- melt(input, measure = 'yield_rate')
Error: measure variables not found in data: yield_rate

# So I tried 

in.melt <- melt(input, measure = 'date.yield_rate')


cast(in.melt, date.yield_rate ~ file)

> cast(in.melt, date ~ file)
Error: Casting formula contains variables not found in molten data: date

# If I try to change it as 

cast(in.melt, date.yield_rate ~ file)    # Gives following error.
Error: Casting formula contains variables not found in molten data: 
date.yield_rate

Sir, it will be a
 great help if you can guide me and once again sinserely apologize for 
reverting so late.

Regards

Amy


--- On Thu, 12/23/10, jim holtman  wrote:

From: jim holtman 
Subject: Re: [R] Writing a single output file
To: "Amy Milano" 
Cc: r-help@r-project.org
Date: Thursday, December 23, 2010, 1:39 PM

This should get you close:

> # get file names
> setwd('/temp')
> fileNames <- list.files(pattern = "file.*.csv")
> fileNames
[1] "file1.csv" "file2.csv" "file3.csv" "file4.csv"
> input <- do.call(rbind, lapply(fileNames, function(.name){
+     .data <- read.table(.name, header = TRUE, as.is = TRUE)
+     # add
 file name to the data
+     .data$file <- .name
+     .data
+ }))
> input
        date yield_rate      file
1 12/23/2010       5.25 file1.csv
2 12/22/2010       5.19 file1.csv
3 12/23/2010       5.25 file2.csv
4 12/22/2010       5.19 file2.csv
5 12/23/2010       5.25 file3.csv
6 12/22/2010       5.19 file3.csv
7 12/23/2010       5.25 file4.csv
8 12/22/2010       5.19 file4.csv
> require(reshape)
> in.melt <- melt(input, measure = 'yield_rate')
> cast(in.melt, date ~ file)
        date file1.csv file2.csv file3.csv file4.csv
1 12/22/2010      5.19      5.19 
     5.19      5.19
2 12/23/2010      5.25      5.25      5.25      5.25
>


On Thu, Dec 23, 2010 at 8:07 AM, Amy Milano  wrote:
> Dear R helpers!
>
> Let me first wish all of you "Merry Christmas and Very Happy New year 2011"
>
> "Christmas day is a day of Joy and Charity,
> May God make you rich in both" - Phillips Brooks
>
> ## 
> 
>
> I have a process which generates number of outputs. The R code for the same 
> is as given below.
>
> for(i in 1:n)
> {
> write.csv(output[i], file = paste("output", i, ".csv", sep = ""), row.names =
 FALSE)
> }
>
> Depending on value of 'n', I get different output files.
>
> Suppose n = 3, that means I am having three output csv files viz. 
> 'output1.csv', 'output2.csv' and 'output3.csv'
>
> output1.csv
> date   yield_rate
> 12/23/2010    5.25
> 12/22/2010    5.19
> .
> .
>
>
> output2.csv
>
> date   yield_rate
>
> 12/23/2010    4.16
>
> 12/22/2010    4.59
>
> .
>
>
 .
>
> output3.csv
>
>
> date   yield_rate
>
>
> 12/23/2010    6.15

[R] Writing a single output file

[Amy Milano]

Dear R helpers!

Let me first wish all of you "Merry Christmas and Very Happy New year 2011"

"Christmas day is a day of Joy and Charity,
May God make you rich in both" - Phillips Brooks

## 


I have a process which generates number of outputs. The R code for the same is 
as given below.

for(i in 1:n)   
{
 
write.csv(output[i], file = paste("output", i, ".csv", sep = ""), row.names = 
FALSE) 
} 

Depending on value of 'n', I get different output files. 

Suppose n = 3, that means I am having three output csv files viz. 
'output1.csv', 'output2.csv' and 'output3.csv'

output1.csv
date   yield_rate
12/23/2010    5.25
12/22/2010    5.19
.
.


output2.csv

date   yield_rate

12/23/2010    4.16

12/22/2010    4.59

.

.

output3.csv


date   yield_rate


12/23/2010    6.15


12/22/2010    6.41


.


.



Thus all the output files have same column names viz. Date and yield_rate. 
Also, I do need these files individually too. 

My further requirement is to have a single dataframe as given below.

Date yield_rate1   yield_rate2    
yield_rate3
12/23/2010   5.25  4.16  
6.15 
12/22/2010   5.19                          4.59                          
6.41
...
...

where yield_rate1 = output1$yield_rate and so on.

One way is to simply create a dataframe as 

df = data.frame(Date = read.csv('output1.csv')$Date, yield_rate1 =  
read.csv('output1.csv')$yield_rate,   yield_rate2 = 
read.csv('output2.csv')$yield_rate,
yield_rate3 = read.csv('output3.csv')$yield_rate)

However, the problem arises when I am not aware how many output files are there 
as n can be 5 or even 100.   

So is it possible to write some loop or some function which will enable me to 
read 'n' files individually and then keeping "Date" common, only pickup the 
yield_curve data from each output file.

Thanking in advance for any guidance.

Regards

Amy




  
[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

[R] How to arrange the data

[Amy Milano]

Dear R helpers

I have one data as given below.

date value1  value2 value3
30-Nov-2010   100 40 61
25-Nov-2010   108 31 88
14-Sep-2010    11 180   56

I want the following output

date name       amount
30-Nov-2010  value1        100
30-Nov-2010  value2 40
30-Nov-2010  value3 61
25-Nov-2010  value1   108
25-Nov-2010  value2     31 
25-Nov-2010      value3         88  
14-Sep-2010  value1    11
14-Sep-2010  value2  180
14-Sep-2010      value3      56


I have presented here a small part of large data. I tried to convert the data 
into matrix, then transpose etc. but things are not working for me. Please guide

Thanking in advance

Amy Milano


  



  
[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Re: [R] Finding root of quadratic equation

[Amy Milano]

Dear Jorge Ivan Velez sir,

Thanks a million for your great solution. You have made my Sunday. Thanks again.

Regards

Amy



--- On Sun, 11/28/10, Jorge Ivan Velez  wrote:

From: Jorge Ivan Velez 
Subject: Re: [R] Finding root of quadratic equation
To: "Amy Milano" 
Cc: "R mailing list" 
Date: Sunday, November 28, 2010, 8:49 AM

Hi Amy,
Not using animation, but this seems to work:


f <- function(x) 0.0016^2 - 0.001^2*x^2 - 0.002^2*(1-x)^2 - 
2*0.7*0.001*0.002*x*(1-x)

curve(f, -1, 1)abline(h = 0, lty = 2, col = 'gray')

uniroot(f, c(-1,1))abline(v = .3203, lty = 2, col = 2)


HTH,Jorge

On Sun, Nov 28, 2010 at 3:43 AM, Amy Milano <> wrote:


Dear R Helpers,



I need to find the root of following equation.



0.0016^2 = (0.001*x)^2 + (0.002 * (1-x))^2 + 2 * 0.7 *0.001*0.002 * x * (1-x).



I had tried using "animation " package as follows.







# My Code





library(animation)

ani.options(nmax = 500)





solu = newton.method(function(x) 0.0016^2 - 0.001^2*x^2 - 0.002^2*(1-x)^2 - 
2*0.7*0.001*0.002*x*(1-x), 1, c(-1,1))



solu$root





# However, I am not getting the solution. Please guide.



Amy

















        [[alternative HTML version deleted]]



__

R-help@r-project.org mailing list

https://stat.ethz.ch/mailman/listinfo/r-help

PLEASE do read the posting guide http://www.R-project.org/posting-guide.html

and provide commented, minimal, self-contained, reproducible code.






  
[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

[R] Finding root of quadratic equation

[Amy Milano]

Dear R Helpers,

I need to find the root of following equation. 

0.0016^2 = (0.001*x)^2 + (0.002 * (1-x))^2 + 2 * 0.7 *0.001*0.002 * x * (1-x).

I had tried using "animation " package as follows.



# My Code


library(animation)
ani.options(nmax = 500)


solu = newton.method(function(x) 0.0016^2 - 0.001^2*x^2 - 0.002^2*(1-x)^2 - 
2*0.7*0.001*0.002*x*(1-x), 1, c(-1,1))

solu$root


# However, I am not getting the solution. Please guide.

Amy







  
[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Re: [R] Using tapply?

[Amy Milano]

Dear Sir,

Thanks a lot for your advice and surely I will be going through your suggestion 
as regards  ?optim. In the mean time, is it possible to guide me regarding one 
general question. 

Suppose instead of using newton.method function, I am using some other function 
resulting in some other process and which is using say C, E, N, R only. (i.e. I 
am not calculating root anymore). My problem is how do I apply this function 
row-wise to a table.

I am not sure whether I am able to put up my query properly. Basically, I need 
to apply the function to a table and store the result row-wise.

Thanks in advance Sir.

Regards

Amy

--- On Mon, 10/25/10, Dennis Murphy  wrote:

From: Dennis Murphy 
Subject: Re: [R] Using tapply?
To: "Amy Milano" 
Cc: r-help@r-project.org
Date: Monday, October 25, 2010, 10:47 AM

Hi:

I'm pretty sure that newton.method in the animation package is meant to 
illustrate the technique rather than to be used as an optimizer in practice. 
Look at ?optim; it that doesn't meet your needs, consult the Optimization Task 
View at CRAN, where you will find several packages, in addition to functions in 
the base package, devoted to function optimization.


HTH,
Dennis

On Mon, Oct 25, 2010 at 12:18 AM, Amy Milano  wrote:

Dear R helpers,



I am trying to calculate the Annualized Percent Rate using following R - Code.



# 



## R Code



library(animation)



# INPUT



C = 25    # Loan Amount

E = 2500  # Other Cost

R = 6 # Interest rate

r = R/1200    # Monthly interest rate

q = 12    # No of Compoundings   

n = 20    # No of years



# 



# COMPUTATIONS    



N = n *

 q # No of months



P = ((C + E)*r*(1+r)^N) / ((1+r)^N - 1)   # Monthly Payments



ani.options(nmax = 500)

solu = newton.method(function(a) C * (a*(1+a)^N) - P * ((1+a)^N - 1), 1, c(R - 
0.25*R, R + 0.25*R))

solu$root



APR = ((1+solu$root)^q-1)*100



# _



## RESULTS P = 1808.988, APR = 6.298708 These are the values I obtain.



# 



## PROBLEM



This R code holds or yields results if I am dealing with only one value for 
each of the input. However,

if there are more than one input values, how do I proceed? Say, E.g.



C = c(25, 40)

E = c(2500, 5000)

R = c(6, 6)

q = c(12, 12)

n = c(20, 20)



So using above code, I am able to obtain the values of P as 1808.988 and 
2901.546 respectively. However, using this code I

 am not able to obtain "solu" as defined above. I tried using the tapply 
instead but seems its not working.



Please guide as to how do I use tapply here.



Regards and thanking in advance



Amy











        [[alternative HTML version deleted]]




__

R-help@r-project.org mailing list

https://stat.ethz.ch/mailman/listinfo/r-help

PLEASE do read the posting guide http://www.R-project.org/posting-guide.html

and provide commented, minimal, self-contained, reproducible code.







  
[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

[R] Using tapply?

[Amy Milano]

Dear R helpers,

I am trying to calculate the Annualized Percent Rate using following R - Code.

# 

## R Code

library(animation)

# INPUT

C = 25    # Loan Amount
E = 2500  # Other Cost
R = 6 # Interest rate
r = R/1200    # Monthly interest rate
q = 12    # No of Compoundings   
n = 20    # No of years

# 

# COMPUTATIONS    

N = n *
 q # No of months

P = ((C + E)*r*(1+r)^N) / ((1+r)^N - 1)   # Monthly Payments

ani.options(nmax = 500)
solu = newton.method(function(a) C * (a*(1+a)^N) - P * ((1+a)^N - 1), 1, c(R - 
0.25*R, R + 0.25*R))
solu$root

APR = ((1+solu$root)^q-1)*100

# _

## RESULTS P = 1808.988, APR = 6.298708 These are the values I obtain.

# 

## PROBLEM

This R code holds or yields results if I am dealing with only one value for 
each of the input. However,
if there are more than one input values, how do I proceed? Say, E.g.

C = c(25, 40)
E = c(2500, 5000)
R = c(6, 6)
q = c(12, 12)
n = c(20, 20)

So using above code, I am able to obtain the values of P as 1808.988 and 
2901.546 respectively. However, using this code I
 am not able to obtain "solu" as defined above. I tried using the tapply 
instead but seems its not working.

Please guide as to how do I use tapply here.

Regards and thanking in advance

Amy




  
[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.