I have a file which contains several thousand numbers, each on it's own line:
34
42
11
6
2
99
...
I'm looking to write a script which will print the sum of all numbers in the file. I've got a solution, but it's not very efficient. (It takes several minutes to run.) I'm looking for a more efficient solution. Any suggestions?
For a Perl one-liner, it's basically the same thing as the awk solution in Ayman Hourieh's answer:
% perl -nle '$sum += $_ } END { print $sum'
If you're curious what Perl one-liners do, you can deparse them:
% perl -MO=Deparse -nle '$sum += $_ } END { print $sum'
The result is a more verbose version of the program, in a form that no one would ever write on their own:
BEGIN { $/ = "\n"; $\ = "\n"; }
LINE: while (defined($_ = <ARGV>)) {
chomp $_;
$sum += $_;
}
sub END {
print $sum;
}
-e syntax OK
Just for giggles, I tried this with a file containing 1,000,000 numbers (in the range 0 - 9,999). On my Mac Pro, it returns virtually instantaneously. That's too bad, because I was hoping using mmap would be really fast, but it's just the same time:
use 5.010;
use File::Map qw(map_file);
map_file my $map, $ARGV[0];
$sum += $1 while $map =~ m/(\d+)/g;
say $sum;
You can use awk:
awk '{ sum += $1 } END { print sum }' file
None of the solution thus far use paste. Here's one:
paste -sd+ filename | bc
As an example, calculate Σn where 1<=n<=100000:
$ seq 100000 | paste -sd+ | bc -l
5000050000
(For the curious, seq n would print a sequence of numbers from 1 to n given a positive number n.)
Just for fun, let's benchmark it:
$ for ((i=0; i<1000000; i++)) ; do echo $RANDOM; done > random_numbers
$ time perl -nle '$sum += $_ } END { print $sum' random_numbers
16379866392
real 0m0.226s
user 0m0.219s
sys 0m0.002s
$ time awk '{ sum += $1 } END { print sum }' random_numbers
16379866392
real 0m0.311s
user 0m0.304s
sys 0m0.005s
$ time { { tr "\n" + < random_numbers ; echo 0; } | bc; }
16379866392
real 0m0.445s
user 0m0.438s
sys 0m0.024s
$ time { s=0;while read l; do s=$((s+$l));done<random_numbers;echo $s; }
16379866392
real 0m9.309s
user 0m8.404s
sys 0m0.887s
$ time { s=0;while read l; do ((s+=l));done<random_numbers;echo $s; }
16379866392
real 0m7.191s
user 0m6.402s
sys 0m0.776s
$ time { sed ':a;N;s/\n/+/;ta' random_numbers|bc; }
^C
real 4m53.413s
user 4m52.584s
sys 0m0.052s
I aborted the sed run after 5 minutes
I've been diving to lua, and it is speedy:
$ time lua -e 'sum=0; for line in io.lines() do sum=sum+line end; print(sum)' < random_numbers
16388542582.0
real 0m0.362s
user 0m0.313s
sys 0m0.063s
and while I'm updating this, ruby:
$ time ruby -e 'sum = 0; File.foreach(ARGV.shift) {|line| sum+=line.to_i}; puts sum' random_numbers
16388542582
real 0m0.378s
user 0m0.297s
sys 0m0.078s
Heed Ed Morton's advice: using $1
$ time awk '{ sum += $1 } END { print sum }' random_numbers
16388542582
real 0m0.421s
user 0m0.359s
sys 0m0.063s
vs using $0
$ time awk '{ sum += $0 } END { print sum }' random_numbers
16388542582
real 0m0.302s
user 0m0.234s
sys 0m0.063s
Another option is to use jq:
$ seq 10|jq -s add
55
-s (--slurp) reads the input lines into an array.
This is straight Bash:
sum=0
while read -r line
do
(( sum += line ))
done < file
echo $sum
Here's another one-liner
( echo 0 ; sed 's/$/ +/' foo ; echo p ) | dc
This assumes the numbers are integers. If you need decimals, try
( echo 0 2k ; sed 's/$/ +/' foo ; echo p ) | dc
Adjust 2 to the number of decimals needed.
I prefer to use R for this:
$ R -e 'sum(scan("filename"))'
I prefer to use GNU datamash for such tasks because it's more succinct and legible than perl or awk. For example
datamash sum 1 < myfile
where 1 denotes the first column of data.
cat nums | perl -ne '$sum += $_ } { print $sum'
(same as brian d foy's answer, without 'END')
Just for fun, lets do it with PDL, Perl's array math engine!
perl -MPDL -E 'say rcols(shift)->sum' datafile
rcols reads columns into a matrix (1D in this case) and sum (surprise) sums all the element of the matrix.
Here is a solution using python with a generator expression. Tested with a million numbers on my old cruddy laptop.
time python -c "import sys; print sum((float(l) for l in sys.stdin))" < file
real 0m0.619s
user 0m0.512s
sys 0m0.028s
$ perl -MList::Util=sum -le 'print sum <>' nums.txt
say sum lines
~$ perl6 -e '.say for 0..1000000' > test.in
~$ perl6 -e 'say sum lines' < test.in
500000500000
sed ':a;N;s/\n/+/;ta' file|bc
More succinct:
# Ruby
ruby -e 'puts open("random_numbers").map(&:to_i).reduce(:+)'
# Python
python -c 'print(sum(int(l) for l in open("random_numbers")))'
I have not tested this but it should work:
cat f | tr "\n" "+" | sed 's/+$/\n/' | bc
You might have to add "\n" to the string before bc (like via echo) if bc doesn't treat EOF and EOL...
Another for fun
sum=0;for i in $(cat file);do sum=$((sum+$i));done;echo $sum
or another bash only
s=0;while read l; do s=$((s+$l));done<file;echo $s
But awk solution is probably best as it's most compact.
With Ruby:
ruby -e "File.read('file.txt').split.inject(0){|mem, obj| mem += obj.to_f}"
I've written an R script to take arguments of a file name and sum the lines.
#! /usr/local/bin/R
file=commandArgs(trailingOnly=TRUE)[1]
sum(as.numeric(readLines(file)))
This can be sped up with the "data.table" or "vroom" package as follows:
#! /usr/local/bin/R
file=commandArgs(trailingOnly=TRUE)[1]
sum(data.table::fread(file))
#! /usr/local/bin/R
file=commandArgs(trailingOnly=TRUE)[1]
sum(vroom::vroom(file))
Same benchmarking data as @glenn jackman.
for ((i=0; i<1000000; i++)) ; do echo $RANDOM; done > random_numbers
In comparison to the R call above, running R 3.5.0 as a script is comparable to other methods (on the same Linux Debian server).
$ time R -e 'sum(scan("random_numbers"))'
0.37s user
0.04s system
86% cpu
0.478 total
R script with readLines
$ time Rscript sum.R random_numbers
0.53s user
0.04s system
84% cpu
0.679 total
R script with data.table
$ time Rscript sum.R random_numbers
0.30s user
0.05s system
77% cpu
0.453 total
R script with vroom
$ time Rscript sum.R random_numbers
0.54s user
0.11s system
93% cpu
0.696 total
For reference here as some other methods suggested on the same hardware
Python 2 (2.7.13)
$ time python2 -c "import sys; print sum((float(l) for l in sys.stdin))" < random_numbers
0.27s user 0.00s system 89% cpu 0.298 total
Python 3 (3.6.8)
$ time python3 -c "import sys; print(sum((float(l) for l in sys.stdin)))" < random_number
0.37s user 0.02s system 98% cpu 0.393 total
Ruby (2.3.3)
$ time ruby -e 'sum = 0; File.foreach(ARGV.shift) {|line| sum+=line.to_i}; puts sum' random_numbers
0.42s user
0.03s system
72% cpu
0.625 total
Perl (5.24.1)
$ time perl -nle '$sum += $_ } END { print $sum' random_numbers
0.24s user
0.01s system
99% cpu
0.249 total
Awk (4.1.4)
$ time awk '{ sum += $0 } END { print sum }' random_numbers
0.26s user
0.01s system
99% cpu
0.265 total
$ time awk '{ sum += $1 } END { print sum }' random_numbers
0.34s user
0.01s system
99% cpu
0.354 total
C (clang version 3.3; gcc (Debian 6.3.0-18) 6.3.0 )
$ gcc sum.c -o sum && time ./sum < random_numbers
0.10s user
0.00s system
96% cpu
0.108 total
Lua (5.3.5)
$ time lua -e 'sum=0; for line in io.lines() do sum=sum+line end; print(sum)' < random_numbers
0.30s user
0.01s system
98% cpu
0.312 total
tr (8.26) must be timed in bash, not compatible with zsh
$time { { tr "\n" + < random_numbers ; echo 0; } | bc; }
real 0m0.494s
user 0m0.488s
sys 0m0.044s
sed (4.4) must be timed in bash, not compatible with zsh
$ time { head -n 10000 random_numbers | sed ':a;N;s/\n/+/;ta' |bc; }
real 0m0.631s
user 0m0.628s
sys 0m0.008s
$ time { head -n 100000 random_numbers | sed ':a;N;s/\n/+/;ta' |bc; }
real 1m2.593s
user 1m2.588s
sys 0m0.012s
note: sed calls seem to work faster on systems with more memory available (note smaller datasets used for benchmarking sed)
Julia (0.5.0)
$ time julia -e 'print(sum(readdlm("random_numbers")))'
3.00s user
1.39s system
136% cpu
3.204 total
$ time julia -e 'print(sum(readtable("random_numbers")))'
0.63s user
0.96s system
248% cpu
0.638 total
Notice that as in R, file I/O methods have different performance.
I couldn't just pass by... Here's my Haskell one-liner. It's actually quite readable:
sum <$> (read <$>) <$> lines <$> getContents
Unfortunately there's no ghci -e to just run it, so it needs the main function, print and compilation.
main = (sum <$> (read <$>) <$> lines <$> getContents) >>= print
To clarify, we read entire input (getContents), split it by lines, read as numbers and sum. <$> is fmap operator - we use it instead of usual function application because sure this all happens in IO. read needs an additional fmap, because it is also in the list.
$ ghc sum.hs
[1 of 1] Compiling Main ( sum.hs, sum.o )
Linking sum ...
$ ./sum
1
2
4
^D
7
Here's a strange upgrade to make it work with floats:
main = ((0.0 + ) <$> sum <$> (read <$>) <$> lines <$> getContents) >>= print
$ ./sum
1.3
2.1
4.2
^D
7.6000000000000005
I don't know if you can get a lot better than this, considering you need to read through the whole file.
$sum = 0;
while(<>){
$sum += $_;
}
print $sum;
Here's another:
open(FIL, "a.txt");
my $sum = 0;
foreach( <FIL> ) {chomp; $sum += $_;}
close(FIL);
print "Sum = $sum\n";
C always wins for speed:
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char **argv) {
ssize_t read;
char *line = NULL;
size_t len = 0;
double sum = 0.0;
while (read = getline(&line, &len, stdin) != -1) {
sum += atof(line);
}
printf("%f", sum);
return 0;
}
Timing for 1M numbers (same machine/input as my python answer):
$ gcc sum.c -o sum && time ./sum < numbers
5003371677.000000
real 0m0.188s
user 0m0.180s
sys 0m0.000s
You can do it with Alacon - command-line utility for Alasql database.
It works with Node.js, so you need to install Node.js and then Alasql package:
To calculate sum from TXT file you can use the following command:
> node alacon "SELECT VALUE SUM([0]) FROM TXT('mydata.txt')"
It is not easier to replace all new lines by +, add a 0 and send it to the Ruby interpreter?
(sed -e "s/$/+/" file; echo 0)|irb
If you do not have irb, you can send it to bc, but you have to remove all newlines except the last one (of echo). It is better to use tr for this, unless you have a PhD in sed .
(sed -e "s/$/+/" file|tr -d "\n"; echo 0)|bc
Just to be ridiculous:
cat f | tr "\n" "+" | perl -pne chop | R --vanilla --slave
