[R] Finding nrows with specefic values&converting a matrix into a table
David L Carlson
dcarlson at tamu.edu
Mon May 1 19:51:00 CEST 2017
Copy your queries to the help list. Do not use html (google "send plain text email using hotmail"). Copy your actual code creating the object and writing with any warning or error message into your email. Do not just give us a description of what you did. Include information about the object you are trying to save using class() and dim(). Without that information, it is not possible to help you. Based on your email, we don't know if the problem is with R or with Excel. Different versions of Excel have different limits for the number of rows and columns.
Why would you try both write.csv() and write.csv2() since they are the same except for how to represent decimal numbers?
Have you tried using read.csv() to read the .csv file you created to see if it is the same size as the one you wrote?
Have you opened the .csv file in a text editor to see if it is properly formatted and contains the number of records you think it does?
David C
From: abo dalash [mailto:abo_dlsh at hotmail.com]
Sent: Sunday, April 30, 2017 7:20 PM
To: David L Carlson <dcarlson at tamu.edu>
Subject: Re: [R] Finding nrows with specefic values&converting a matrix into a table
I have been trying to export the file for about 5 hours now without a result!
I have read what is in the manual but did not find any formats except write.table(),write.csv(), write.csv2(). No one works. I have also highlighted
all table in R and copied it into an excel file but this has just copied
the first 200 rows and I have about 15000 rows. All my tries end with exporting all columns in a single column in the new file without separation.
________________________________________
From: David L Carlson <dcarlson at tamu.edu>
Sent: 01 May 2017 02:54 AM
To: abo dalash; r-help at R-project.org
Subject: RE: [R] Finding nrows with specefic values&converting a matrix into a table
No. You are not using the correct command. Time to read the manual:
?write.table
You will find the answer to your question by looking at the alternate forms of write.*().
David L. Carlson
Department of Anthropology
Texas A&M University
From: abo dalash [mailto:abo_dlsh at hotmail.com]
Sent: Sunday, April 30, 2017 2:36 PM
To: David L Carlson <dcarlson at tamu.edu>; r-help at R-project.org
Subject: RE: [R] Finding nrows with specefic values&converting a matrix into a table
I'm trying to write the table I have created from the matrix using
write.table(mytable, file= "mytable.txt"). I have imported this txt. file into
an Excel sheet but all data have been typed in one column (Var1,Var2,&Freq.)
and I want to see each vector in one column. Have I used the correct syntax?
Regards
________________________________________
From: David L Carlson <dcarlson at tamu.edu>
Sent: 30 April 2017 07:33 PM
To: abo dalash; r-help at R-project.org
Subject: RE: [R] Finding nrows with specefic values&converting a matrix into a table
Show us the code you used. Don't just tell us what you did. It is likely that something you did after creating the matrix converted it to a data frame. Copy and paste your code to your emails.
> str(mydf)
'data.frame': 3 obs. of 3 variables:
$ x: int 0 NA NA
$ y: int 5 0 NA
$ z: int 67 23 0
> data.frame(as.table(as.matrix(mydf)))
Var1 Var2 Freq
1 x x 0
2 y x NA
3 z x NA
4 x y 5
5 y y 0
6 z y NA
David C
From: abo dalash [mailto:abo_dlsh at hotmail.com]
Sent: Sunday, April 30, 2017 11:13 AM
To: David L Carlson <dcarlson at tamu.edu>
Subject: Re: [R] Finding nrows with specefic values&converting a matrix into a table
str(mymatrix)
The Structure shows that this is a 'data.frame'? of 120 obs. and 120 variables
of numeric type. R deals with my matrix as a data frame although I used
the function matrix() to produce this matrix which is not clear to me why. As this is already a data.frame, this may explains why R returns me the same
matrix. What do you recommend now?
Many thanks
________________________________________
From: David L Carlson <dcarlson at tamu.edu>
Sent: 30 April 2017 06:47 PM
To: abo dalash; r-help at R-project.org
Subject: RE: [R] Finding nrows with specefic values&converting a matrix into a table
You did not give me any information about about your data using str() or class() so I'll guess that you have a matrix, e.g.:
> class(moredata)
[1] "matrix"
> as.data.frame.table(moredata)
Var1 Var2 Freq
1 x x 0
2 y x NA
3 z x NA
4 x y 5
5 y y 0
6 z y NA
7 x z 67
8 y z 23
9 z z 0
David C
From: abo dalash [mailto:abo_dlsh at hotmail.com]
Sent: Sunday, April 30, 2017 10:09 AM
To: David L Carlson <dcarlson at tamu.edu>; r-help at R-project.org
Subject: Re: [R] Finding nrows with specefic values&converting a matrix into a table
Dear David ..,
Many thanks for this detailed answer.
Your guidance reg. the first task has resolved my issue and I have understood now how to perform this type of analysis. I have saved your learning tips in my script.
Reg. the Matrix-table conversion, could you please clarify this more?.
I applied the function as.data.frame but this returned the same matrix
without converting it into a list table. I'm not sure where is the problem
in my code : mymatrix <- as.data.frame(mymatrix).
Many thanks for your support
Regards
________________________________________
From: David L Carlson <dcarlson at tamu.edu>
Sent: 29 April 2017 11:38 PM
To: abo dalash; r-help at R-project.org
Subject: RE: [R] Finding nrows with specefic values&converting a matrix into a table
First. Do not use html messages, only plain text. Second. Provide a small example data set, preferably using dput(). Just printing your data can hide important information. Third. Read the documentation. Your first example does not return a logical vector at all:
> dput(mydata)
structure(list(Col1 = c(123L, 443L, 566L), Col2 = c(566L, 54L,
44L), Col3 = c(235L, 566L, 235L)), .Names = c("Col1", "Col2",
"Col3"), class = "data.frame", row.names = c(NA, -3L))
> which(mydata == 566,235)
row col
[1,] 3 1
[2,] 1 2
[3,] 2 3
It locates cells with 566, but not 235 which is not a surprise because you did not provide a valid logical expression to which().
There are a number of ways to get what you want, but since you want to process rows, apply() is straightforward:
> Val566 <- apply(mydata, 1, function(x) any(x == 566))
> Val566
[1] TRUE TRUE TRUE
> Val235 <- apply(mydata, 1, function(x) any(x == 235))
> Val235
[1] TRUE FALSE TRUE
> which(Val235 & Val566)
[1] 1 3
You should read the manual pages on any(), apply(), dput() and which() and logical expressions:
> ?apply
> ?any
> ?dput
> ?which
> ?Comparison # ?"==" will also get you there.
For the second question, assuming you are beginning with a table object as R defines that term and not a matrix (since all tables are matrices, but all matrices are not tables):
> dput(moredata)
structure(c(0L, NA, NA, 5L, 0L, NA, 67L, 23L, 0L), .Dim = c(3L,
3L), .Dimnames = list(c("x", "y", "z"), c("x", "y", "z")), class = "table")
> moredata
x y z
x 0 5 67
y NA 0 23
z NA NA 0
Note, that your example uses na rather than NA. R is case sensitive so na is just an ordinary character string while NA is a missing value indicator. This is one of the reasons that dput() is important
> moredata.df <- as.data.frame(moredata)
> moredata.df
Var1 Var2 Freq
1 x x 0
2 y x NA
3 z x NA
4 x y 5
5 y y 0
6 z y NA
7 x z 67
8 y z 23
9 z z 0
> moredata.df[order(moredata.df$Freq, decreasing=TRUE), ]
Var1 Var2 Freq
7 x z 67
8 y z 23
4 x y 5
1 x x 0
5 y y 0
9 z z 0
2 y x NA
3 z x NA
6 z y NA
For this you should read the following manual pages:
> ?as.data.frame
> ?order
> ?Extract
-------------------------------------
David L Carlson
Department of Anthropology
Texas A&M University
College Station, TX 77840-4352
-----Original Message-----
From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of abo dalash
Sent: Saturday, April 29, 2017 10:14 AM
To: r-help at R-project.org
Subject: [R] Finding nrows with specefic values&converting a matrix into a table
Hi All
I'm trying to identify number of rows containing 2 specific values.
I tried : which(mydata == 566,235), but this returns logical values for all rows and any T in a certain row indicates the existence of one of these values but what I need to know is only number of rows in my data set with these 2 particular values considering these two values
as one pair per column. For example :
1 123 566 235
2 443 54 566
3 566 44 235
here number of rows with the values 566&235 is 2 which are
rows 1 & 3. Row 2 has only 566 so it should not be included in
our calculation.
I also have a large matrix and wanted to convert it into a table so I can
easily identify the combination with higher frequencies.
The matrix looks like this:
x y z
x 0 5 67
y na 0 23
z na na 0
and I would like to convert this into a table arranged with
higher values first like this :
x z 67
y z 23
x y 5
x x 0
y y 0
z z 0
y x na
z x na
z y na
Is there simple function to perform this conversion with some explanation about the Syntax
Regards
[[alternative HTML version deleted]]
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