How to Assign Output of Cat to an Object

How to assign output of cat to an object?

Instead of cating to a file, why not use the paste command to generate a string instead?

> paste(test, collapse="\n")
[1] "V 1\nx\n1 2 3\ny\n3 5 8\nV 2\nx\ny\nV 3\ny\n7 2 1\nV 4\nx\n9 3 7\ny"

Now instead of doing a cat then readlines you can just pass this string directly into strsplit.

How do I assign the output of cat to an object in a list?

Capture the output as out, insert ABC and perform the replacement giving character vector v, collapse that to a single newline separated string giving s. Now assign v or s to the list component as in the question depending on what you want. (Can omit the line creating s if v is assigned.)

out <-  capture.output(summary(aov(savings ~ single, data = credit)))
v <- c("ABC", sub("Pr(>F)", "p-value", out, fixed = TRUE), "\n") # char vec
s <- paste(v, collapse = "\n") # single string

The result of cat(s) is:

ABC
             Df Sum Sq Mean Sq F value p-value  
single        1     94   93.72   3.415 0.0652 .
Residuals   498  13668   27.45                 
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

custom class with print method

I am not sure that the added complexity is worth it but if you really want to create an object which displays itself nicely you can create a new class with a custom print method:

print.selfcat <- cat
obj <- structure(s, class = "selfcat")
obj  # result is same as for cat(s)

summary.aov subclass

Another possibility is to create a subclass of summary.aov class, summary.aov2 which adds a name attribute and a print method to wrap up everything above together:

# convert summary.aov class to summary.aov2 class
as.summary.aov2 <- function(x, name = "", ...) {
  structure(x, name = name, class = c("summary.aov2", "summary.aov"))
}

print.summary.aov2 <- function(x, ...) {
  out <-  capture.output(structure(x, class = "summary.aov"))
  v <- c(attr(x, "name"), sub("Pr(>F)", "p-value", out, fixed = TRUE), "\n") 
  s <- paste(v, collapse = "\n")
  cat(s, ...)
}

# test
library(fpp)
modsum <- summary(aov(savings ~ single, data = credit))
modsum2 <- as.summary.aov2(modsum, name = "ABC") # create new object w name
modsum2

giving:

ABC
             Df Sum Sq Mean Sq F value p-value  
single        1     94   93.72   3.415 0.0652 .
Residuals   498  13668   27.45                 
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

How to assign a cat() value to an object in r

cat doesn't have a return value. It just print. We could write the output to a file by specifying the file argument

cat(dQuote(paste0("Equal = ", paste("(", vars, ", Slope[0])",
                                      collapse=",\n ", sep=""), ";"), FALSE),
     file = 'file.txt')

---

The dQuote output can be assigned and not the cat wrapped on it

aa <- dQuote(paste0("Equal = ", paste("(", vars, ", Slope[0])",
                                      collapse=",\n ", sep=""), ";"), FALSE)

save extracted (using cat) text in a variable in R

You need to use capture.output in this case.

var2 <- capture.output(cat(sub('.*"(.*)".*', "\\1", var1)))
var2

Look at this question.

Getting the output of a cat command into an array

readarray array < <(awk '/swap/{print $1}' /proc/swaps)

How to assign the output of dput() into an object or insert the double quote and then comma after every words?

write.table to clipboard works.

    write.table(t(as.vector(x)), "clipboard", row.names = FALSE, col.names = FALSE, sep = ",")

then ctrl+V to script returns

    "ACCN-NJ-A55O-01A-11D-A25L-08","ACCN-NJ-A55O-11D-11D-A25L-08","ACCN-05-4249-01A-01D-1105-08","ACCN-S2-AA1A-15C-12D-A397-08"

I'm not sure if this is what you wanted.

bash : cat commands output only if it success

Perhaps capture the output into a variable, and echo the variable into the file if the exit status is zero:

output=$(command) && echo "$output" > file

Testing

$ out=$(bash -c 'echo good output') && echo "$out" > file
$ cat file
good output

$ out=$(bash -c 'echo bad output; exit 1') && echo "$out" > file
$ cat file
good output

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