Months in gnuplot - bash

Question

I have a csv file with 12 numbers which correspond to the 12 months. An example of the file is as follows:
$ cat data.csv
"3","5","6","5","4","6","7","6","4","4","3","3",
I'd like to plot these with the months in the x-axis using "January, February, March and so on."
I've found this script but I don't know how to input the months:
for FILE in data.csv; do
gnuplot -p << EOF
set datafile separator ","
set xlabel "xlabel"
set ylabel "ylabel"
set title "graphTitle"
plot "$FILE" using $xcolumn:$ycolumn
EOF
done
The expected output should be a plot where the x-axis is the month and the y-axis is the data from the csv file.
Note that in the CSV file there aren't the months, just the numbers. That's why I am asking what is the best way to achieve this without having to enter them manually in the CSV or looping through an array. Is there any gnuplot function that adds the date and can be formatted?
Thank you

Answer 1

If you do not mind typing in the month names, I think the simplest is this. Data is shown in-line for clarity rather than reading from a file.
$DATA << EOD
"3","5","6","5","4","6","7","6","4","4","3","3",
EOD
set datafile sep comma
set xrange [0:13]
unset key
array Month[12] = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
plot for [N=1:12] $DATA using (N):(column(N)):xticlabel(Month[N]) with impulse lw 5
If you do not want to type in the month names, the following should generate the equivalent. "%b" will generate the abbreviated month names as above. "%B"would generate the full month name.
Month(i) = strftime("%b", i * 3600.*24.*28.)
plot for [N=1:12] $DATA using (N):(column(N)):xticlabel(Month(N)) with impulse lw 5

Answer 2

If you don't want to use the loop syntax, there is a way to read your CSV file as a 1x12 matrix. Also, for long month names, you can use gnuplot's strftime function by giving it the format specifier "%B".
The gnuplot script is here.
set key noautotitle
set datafile separator comma
set yrange [0:10]
set xrange [-1:12]
set xtics rotate by -45
set grid xtics
# This function generates the names "January", "February", ...
# from the integer value 0, 1, ...
#
monthname(i) = strftime("%B",strptime("%m",sprintf("%i",i+1)))
# `matrix every ...` specifier tells to read the data as a 1x12 matrix.
#
plot "data.csv" matrix every :::0:11:0 using 1:3:xtic(monthname($1)) with linespoints pt 7

Answer 3

UPDATE: After reviewing OPs post and code some more, I'm guessing the desired format looks like:
January:"3",February:"5",March:"6",April:"5",May:"4",June:"6",July:"7",August:"6",September:"4",October:"4",November:"3",December:"3",
If this is the case, we can use the same solution (below) and pipe the final results through tr to transpose the data back to a single-line/multi-column dataset, eg:
$ paste -d" " <(locale mon | tr ';' '\n') <(tr ',' '\n' < data.csv) | grep -v '^ $' | tr ' \n' ':,'
January:"3",February:"5",March:"6",April:"5",May:"4",June:"6",July:"7",August:"6",September:"4",October:"4",November:"3",December:"3",
And updating OPs code:
datfile=$(mktemp)
for FILE in data.csv
do
paste -d" " <(locale mon | tr ';' '\n') <(tr ',' '\n' < data.csv) | grep -v '^ $' | tr ' \n' ':,' > "${datfile}"
gnuplot -p <<-EOF
set datafile separator ","
set xlabel "xlabel"
set ylabel "ylabel"
set title "graphTitle"
plot "${datfile}" using $xcolumn:$ycolumn
EOF
done
'rm' -rf "${datfile}" > /dev/null 2>&1
Looks like gnuplot can accept data in various formats, including the following:
January "3"
February "5"
March "6"
April "5"
May "4"
June "6"
July "7"
August "6"
September "4"
October "4"
November "3"
December "3"
NOTE: If OP determines this is not an acceptable file format then I'm sure we can come up with something else ... would just need the question updated with a sample of a valid file format showing months and numerics.
So if we can generate this data set on the fly we could then feed it to gnuplot ...
First we'll let locale generate the months for us:
$ locale mon
January;February;March;April;May;June;July;August;September;October;November;December
Next we can transpose our single-line/multi-column datasets to multi-line/single-column datasets:
$ locale mon | tr ';' '\n'
January
February
March
April
May
June
July
August
September
October
November
December
$ tr ',' '\n' < data.csv
"3"
"5"
"6"
"5"
"4"
"6"
"7"
"6"
"4"
"4"
"3"
"3"
From here we can paste these 2 datasets together, using a space as the column delimiter:
$ paste -d" " <(locale mon | tr ';' '\n') <(tr ',' '\n' < data.csv)
January "3"
February "5"
March "6"
April "5"
May "4"
June "6"
July "7"
August "6"
September "4"
October "4"
November "3"
December "3"
One last step would be to write this to a (tmp) file, eg:
$ datfile=$(mktemp)
$ paste -d" " <(locale mon | tr ';' '\n') <(tr ',' '\n' < data.csv) | grep -v '^ $' > "${datfile}"
$ cat "${datfile}"
January "3"
February "5"
March "6"
April "5"
May "4"
June "6"
July "7"
August "6"
September "4"
October "4"
November "3"
December "3"
NOTE: The grep -v '^ $' is to get rid of the extra line at the end related to the last comma (,) in data.csv
From here "${datfile}" can be fed to gnuplot as needed and once no longer needed deleted, eg:
$ gnuplot ... "${datfile}" ...
$ 'rm' -rf "${datfile}" > /dev/null 2>&1

Answer 4

Yet another solution. Because you have a trailing comma and gnuplot expects a number after it, you will get a warning warning: matrix contains missing or undefined values which you can ignore. Therefore, you should limit the x-maximum to smaller 12.
In your case, replace $Data with your filename 'data.csv'. You might want to set another locale (check help locale) to get other languages for the months' names.
Code:
### plot monthly data
reset session
$Data <<EOD
"3","5","6","5","4","6","7","6","4","4","3","3",
EOD
set datafile separator comma
set boxwidth 0.8
set style fill solid 0.5
set yrange[0:10]
set xrange[-0.9:11.9]
myMonth(i) = strftime("%b",i*3600*24*31) # get month name as abbreviation, use %B for full name
plot $Data matrix u 1:0:xtic(myMonth($1)) w boxes title "my data"
### end of code
Result:

Answer 5

One awk solution built around the same logic as the paste answer, but which eliminates a few sub-processes (eg, grep, multiple tr's) ...
awk -F'[;,]' ' # input field delimiters are ";" and ","
BEGIN { OFS=":" ; ORS="," } # set output field delimiter as ":" and output record delimiter as ","
FNR==NR { for (i=1 ; i<=NF ; i++) # loop through fields from first file ...
month[i]=$(i) # store in our month[] array
next # skip to next input line
}
{ for (i=1 ; i< NF ; i++) # loop through fields from second file ...
print month[i],$(i) # print month and current field
}
' <(locale mon) data.csv
This generates:
January:"3",February:"5",March:"6",April:"5",May:"4",June:"6",July:"7",August:"6",September:"4",October:"4",November:"3",December:"3",
Rolling this into OP's code:
datfile=$(mktemp)
for FILE in data.csv
do
awk -F'[;,]' 'BEGIN{OFS=":";ORS=","} FNR==NR {for (i=1;i<=NF;i++) mon[i]=$(i); next} {for (i=1;i<NF;i++) print mon[i],$(i)}' <(locale mon) data.csv > "${datfile}"
gnuplot -p <<-EOF
set datafile separator ","
set xlabel "xlabel"
set ylabel "ylabel"
set title "graphTitle"
plot "${datfile}" using $xcolumn:$ycolumn
EOF
done
'rm' -rf "${datfile}" > /dev/null 2>&1