I have a very large csv file (1.4 million rows). It is supposed to have 22 fields and 21 commas in each row. It was created by taking quarterly text files and compiling them into one large text file so that I could import into SQL. In the past, one field was not in the file. I don't have the time to go row by row and check for this.
In R, is there a way to verify that each row has 22 fields or 21 commas? Below is a small sample data set. The possibly missing field is the 0 in the 10th slot.
32,01,01,01,01,01,000000,123,456,0,132,345,456,456,789,235,256,88,4,1,2,1
32,01,01,01,01,01,000001,123,456,0,132,345,456,456,789,235,256,88,5,1,2,1
you can use the base R function count.fields to do this:
count.fields(tmp, sep=",")
[1] 22 22
The input for this function is the name of a file or a connection. Below, I supplied a textConnection. For large files, you would probably want to feed this into table:
table(count.fields(tmp, sep=","))
Note that this can also be used to count the number of rows in a file using length, similar to the output of wc -l in the *nix OSs.
data
tmp <- textConnection(
"32,01,01,01,01,01,000000,123,456,0,132,345,456,456,789,235,256,88,4,1,2,1
32,01,01,01,01,01,000001,123,456,0,132,345,456,456,789,235,256,88,5,1,2,1"
)
Assuming df is your dataframe
apply(df, 1, length)
This will give you the length of each row.
Related
I have a problem importing a file in R. The file correctly organized must contain 5 million records and 22 columns. I cannot separate the data base properly. I tried it with this code:
content <- scan("filepath",'character',sep='~') # Read the file as a single line
# To split content in lines:
lines <- regmatches(content,gregexpr(".{211}",content)) #Each line must have 211 characters with 5 million rows in total
x <- tempfile()
library(erer)
write.list(lines,x)
data <- read.fw(x, widths = c(12,9,9,3,4,8,1,1,3,3,3,1,12,14,13,30,8,9,12,6,6,27))
unlink(x)
Each record has numbers and letters. I don't know what I can correct to separate in columns properly.
All rows looks like this:
1000100060040000000000808040512000000188801072010010010000000000000 CABANILLAS GONZALES MARIA MANUEL CABANILLAS MARIA GONZALES 00000000000000000000000
I want to separate it according to the widths specified in the function
It includes some spaces that I cannot include in the final view
I have excel file that contains numeric variables, but the first column (index column) uses custom formatting: those are numbers that should be presented as text (or similar to text) and having always fixed number of digits where some are zeroes. Here is my example table from excel:
And here is formatting for bad_col1 (rest are numbers or general):
When I try to import my data by using read.xlsx function from either openxlsx or xlsx package it produces something like this:
read.xlsx(file_dir,sheet=1)#for openxlsx
bad_col1 col2 col3
1 5 11 974
2 230 15 719
3 10250 6 944
4 2340 7 401
So as you can see, zeroes are gone. Is there any way to read 1st column as "text" and as other numeric? I can not convert it to text after, because "front zeroes" are gone arleady. I can think of workaround, but it would be more feasible for my project to have them converted while importing.
Thank you in Advance
You can use a vector to filter your desired format, with library readxl:
library(readxl)
filter <- c('text','numeric','numeric')
the_file <- read_xlsx("sample.xlsx", col_types = filter)
Even more, you can skip columns if you use in your filter 'skip' in the desired position, considering that you might have many columns.
Regards
With this https://readxl.tidyverse.org/reference/read_excel.html you can use paramater col_types so that first column is read as character.
I have a series of data frames in my R environment the I have read in as follows:
x <- list.files(pattern="nuc_occupancy_region");
for(i in seq_along(x)){
print(x[i])
assign(paste(x[i]), read.table(x[i], sep='\t', header=T, fill=T))
}
ESC=ls()[grep(ls(), pattern='ESC_nuc')]
MEF=ls()[grep(ls(), pattern='MEF_nuc')]
The list of files MEF often have missing data:
eg.
from command line
head MEF_nuc_occupancy_regionCybb9049012-9053217chrX.txt
9049012 26
9049013
9049014 29
9049015
9049016 26
etc.
The above file is not a problem as the missing values will be read as NA's and I can deal with that later.
However, in others the second value of the first row is missing....
117755994
117755995
117755996
117755997 6
117755998 6
117755999 6
so despite the fact that each file has 2 columns, the lack of a second value in the first row of some of them causes them to be recognised as a file with a single column:
read.table(example.txt, sep='\t', header=T, fill=T)
117755994
117755995
117755996
117755997
6
117755998
6
117755999
6
Is there some way to avoid this as I need all the data frames to be in 2D?
Thanks
I had to just sort it out with python as 'readlines()' is unbiased to column number:
import os
list=os.listdir('.')
counter=0
files=[]
for i in list:
file=open(i, 'r')
print file
lines=file.readlines()
file.close()
corrected=open(i+'formatted', 'a')
print lines[0:9]
for line in lines:
line=line.rstrip('\n')
line=line.split()
if len(line)<2:
line.append(0)
corrected.write("{}\t{}\n".format(line[0], line[1]))
else:
corrected.write("{}\t{}\n".format(line[0], line[1]))
corrected.close()
I apologize in advance for the somewhat lack of reproducibility here. I am doing an analysis on a very large (for me) dataset. It is from the CMS Open Payments database.
There are four files I downloaded from that website, read into R using readr, then manipulated a bit to make them smaller (column removal), and then stuck them all together using rbind. I would like to write my pared down file out to an external hard drive so I don't have to read in all the data each time I want to work on it and doing the paring then. (Obviously, its all scripted but, it takes about 45 minutes to do this so I'd like to avoid it if possible.)
So I wrote out the data and read it in, but now I am getting different results. Below is about as close as I can get to a good example. The data is named sa_all. There is a column in the table for the source. It can only take on two values: gen or res. It is a column that is actually added as part of the analysis, not one that comes in the data.
table(sa_all$src)
gen res
14837291 822559
So I save the sa_all dataframe into a CSV file.
write.csv(sa_all, 'D:\\Open_Payments\\data\\written_files\\sa_all.csv',
row.names = FALSE)
Then I open it:
sa_all2 <- read_csv('D:\\Open_Payments\\data\\written_files\\sa_all.csv')
table(sa_all2$src)
g gen res
1 14837289 822559
I did receive the following parsing warnings.
Warning: 4 parsing failures.
row col expected actual
5454739 pmt_nature embedded null
7849361 src delimiter or quote 2
7849361 src embedded null
7849361 NA 28 columns 54 columns
Since I manually add the src column and it can only take on two values, I don't see how this could cause any parsing errors.
Has anyone had any similar problems using readr? Thank you.
Just to follow up on the comment:
write_csv(sa_all, 'D:\\Open_Payments\\data\\written_files\\sa_all.csv')
sa_all2a <- read_csv('D:\\Open_Payments\\data\\written_files\\sa_all.csv')
Warning: 83 parsing failures.
row col expected actual
1535657 drug2 embedded null
1535657 NA 28 columns 25 columns
1535748 drug1 embedded null
1535748 year an integer No
1535748 NA 28 columns 27 columns
Even more parsing errors and it looks like some columns are getting shuffled entirely:
table(sa_all2a$src)
100000000278 Allergan Inc. gen GlaxoSmithKline, LLC.
1 1 14837267 1
No res
1 822559
There are columns for manufacturer names and it looks like those are leaking into the src column when I use the write_csv function.
I am new to R and my question should be trivial. I need to create a word cloud from a txt file containing the words and their occurrence number. For that purposes I am using the snippets package.
As it can be seen at the bottom of the link, first I have to create a vector (is that right that words is a vector?) like bellow.
> words <- c(apple=10, pie=14, orange=5, fruit=4)
My problem is to do the same thing but create the vector from a file which would contain words and their occurrence number. I would be very happy if you could give me some hints.
Moreover, to understand the format of the file to be inserted I write the vector words to a file.
> write(words, file="words.txt")
However, the file words.txt contains only the values but not the names(apple, pie etc.).
$ cat words.txt
10 14 5 4
Thanks.
words is a named vector, the distinction is important in the context of the cloud() function if I read the help correctly.
Write the data out correctly to a file:
write.table(words, file = "words.txt")
Create your word occurrence file like the txt file created. When you read it back in to R, you need to do a little manipulation:
> newWords <- read.table("words.txt", header = TRUE)
> newWords
x
apple 10
pie 14
orange 5
fruit 4
> words <- newWords[,1]
> names(words) <- rownames(newWords)
> words
apple pie orange fruit
10 14 5 4
What we are doing here is reading the file into newWords, the subsetting it to take the one and only column (variable), which we store in words. The last step is to take the row names from the file read in and apply them as the "names" on the words vector. We do the last step using the names() function.
Yes, 'vector' is the proper term.
EDIT:
A better method than write.table would be to use save() and load():
save(words. file="svwrd.rda")
load(file="svwrd.rda")
The save/load combo preserved all the structure rather than doing coercion. The write.table followed by names()<- is kind of a hassle as you can see in both Gavin's answer here and my answer on rhelp.
Initial answer:
Suggest you use as.data.frame to coerce to a dataframe an then write.table() to write to a file.
write.table(as.data.frame(words), file="savew.txt")
saved <- read.table(file="savew.txt")
saved
words
apple 10
pie 14
orange 5
fruit 4