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6.1. Output
6.1.1. print
The simplest command to output data is print() but if you want to print many things inside print you will need to use the paste() command.
> print("hello world")
[1] "hello world"
> x <- 1
> print(paste("hello world, x=", x))
[1] "hello world, x= 1"
# example for which print is not recommended
> x <- c(1:3)
> print(paste("hello world, x=", x))
[1] "hello world, x= 1" "hello world, x= 2" "hello world, x= 3"
6.1.2. write.table, write.csv
Use write.table() or write.csv() to save a data frame.
mydata <- data.frame(col1 = c(1:3), col2 = c(4:6))
> mydata
col1 col2
1 1 4
2 2 5
3 3 6
> write.table("outputfile.RData")
richer@nano:~/dev/R$ cat outputfile.RData
"col1" "col2"
"1" 1 4
"2" 2 5
"3" 3 6
> mydata <- data.frame(col1 = rnorm(3), col2 = rnorm(3))
> mydata
col1 col2
1 0.1251068 0.3132729
2 1.3635986 1.0170974
3 -0.2699093 1.0902407
> write.fwf(mydata, width=c(12,12))
col1 col2
0.1251068 0.3132729
1.3635986 1.0170974
-0.2699093 1.0902407
write.table(mydata, "mydata.Rdata", sep="\t")
# or save in CSV format
write.csv(mydata, "mydata.csv")
6.1.3. Print nice tables
Use the gridExtra library.
> install.packages("gridExtra")
> library(gridExtra)
> pdf("mydata.pdf", height=11, width=8.5)
> grid.table(mydata)
> dev.off()
The result is the following: mydata.pdf
6.1.4. Execute R code inside PHP web page
Download PHPR and install it in the directory where you will call R your public_html directory.
Install requirements using composer, you should have the composer.json file of PHPR in this directory.
richer@nano:~/public_html\$ composer install
### example #####
public_html
├── call_R.php
├── composer.json
├── src <-- directory in which you will have Kachkaev/PHPR
└── vendor <-- directory in which you will have autoload.php
Then write the following code but modify the path to R depending on your system:
<?php
require_once 'vendor/autoload.php';
use Kachkaev\PHPR\RCore;
use Kachkaev\PHPR\Engine\CommandLineREngine;
$r = new RCore(new CommandLineREngine('/usr/bin/R'));
$result = $r->run(<<<EOF
x = c(1,2,3)
y = c(4,5,6)
z = x + y
z
EOF
);
echo "<pre>$result</pre>";
?>
You should obtain the following result (although I have noticed on my computer that in some occasions you won't get the last two lines):
