I am trying to display the Pythagorean Theorem in bash for my son - which should be easy. I need it in function. However the theorem a2 + b2 = c2 is just not making sense here. Don't know what I am doing wrong.
#!/bin/bash
read side_a side_b
hypo=$(( (side_a*side_a) + (side_b*side_b) ))
echo "side: $side_a side: $side_b hypotenuse: $hypo"
$ /tmp/hypo
5 5
side: 5 side: 5 hypotenuse: 50
time to switch to awk
$ awk '{print "side:",$1,"side:",$2,"hypotenuse:",sqrt($1^2+$2^2)}'
3 4
side: 3 side: 4 hypotenuse: 5
$1 and $2 are the input fields, the rest should read trivially.
With little more effort, you can generate the integer solutions as well...
$ awk 'BEGIN{for(i=1;i<=10;i++) for(j=1;j<i;j++) print 2*i*j, i^2-j^2, i^2+j^2}'
4 3 5
6 8 10
12 5 13
8 15 17
16 12 20
24 7 25
10 24 26
20 21 29
30 16 34
40 9 41
12 35 37
...
Related
I want to generate a sequence of integer numbers between 2 included bounds. I tried with seq, but I could only get the following:
$ low=10
$ high=100
$ n=8
$ seq $low $(( (high-low) / (n-1) )) $high
10
22
34
46
58
70
82
94
As you can see, the 100 is not included in the sequence.
I know that I can get something like that using jot:
$ jot 8 10 100
10
23
36
49
61
74
87
100
But the server I use does not have jot installed, and I do not have permission to install it.
Is there a simple method that I could use to reproduce this behaviour without jot?
If you don't mind launching an extra process (bc) and if it's available on that machine, you could also do it like this:
$ seq -f'%.f' 10 $(bc <<<'scale=2; (100 - 10) / 7') 100
10
23
36
49
61
74
87
100
Or, building on oguz ismail's idea (but using a precision of 4 decimal places):
$ declare -i low=10
$ declare -i high=100
$ declare -i n=8
$ declare incr=$(( (${high}0000 - ${low}0000) / (n - 1) ))
$
$ incr=${incr::-4}.${incr: -4}
$
$ seq -f'%.f' "$low" "$incr" "$high"
10
23
36
49
61
74
87
100
You can try this naive implementation of jot:
jot_naive() {
local -i reps=$1 begin=${2}00 ender=${3}00
local -i x step='(ender - begin) / (reps - 1)'
for ((x = begin; x <= ender; x += step)); do
printf '%.f\n' ${x::-2}.${x: -2}
done
}
You could use awk for that:
awk -v reps=8 -v begin=10 -v end=100 '
BEGIN{
step = (end - begin) / (reps-1);
for ( f = i = begin; i <= end; i = int(f += step) )
print i
}
'
10
22
35
48
61
74
87
100
UPDATE 1 ::: fixed double-printing of final row due to difference less than tiny value of epsilon
to maintain directional consistency, rounding is performed based on sign of final :
—- e.g. if final is negative, then any rounding is done as if the current step value (CurrSV) is negative, regardless of sign of CurrSV
———————————————
while i haven't tested every single possible edge case, i believe this version of the code should handle both positive and negative rounding properly, for the most part.
that said, this isn't a jot replacement at all - it only implements a very small subset of the steps counting feature instead of being a full blown clone of it:
{m,g}awk '
function __________(_) {
return -_<+_?_:-_
}
BEGIN {
CONVFMT = "%.250g"; OFMT = "%.13f"
_____ = (_+=_^=_______=______="")^-_^!_
} {
____ = (((_=$(__=(___=$NF)^(_<_)))^(_______=______="")*___\
)-(__=$++__))/--_
_________ = (_____=(-(_^=_<_))^(________=+____<-____\
)*(_/++_))^(++_^_++-+_*_--+-_)
if (-___<=+___) {
_____=__________(_____)
_________=__________(_________)
}
do { print ______,
++_______, int(__+_____), -____+(__+=____)
} while(________? ___<(__-_________) : (__+_________)<___)
print ______, ++_______, int(___+_____), ___, ORS
}' <<< $'8 -3 -100\n8 10 100\n5 -15 -100\n5 15 100\n11 100 11\n10 100 11'
|
1 -3 -3
2 -17 -16.8571428571429
3 -31 -30.7142857142857
4 -45 -44.5714285714286
5 -58 -58.4285714285714
6 -72 -72.2857142857143
7 -86 -86.1428571428572
8 -100 -100
1 10 10
2 23 22.8571428571429
3 36 35.7142857142857
4 49 48.5714285714286
5 61 61.4285714285714
6 74 74.2857142857143
7 87 87.1428571428572
8 100 100
1 -15 -15
2 -36 -36.2500000000000
3 -58 -57.5000000000000
4 -79 -78.7500000000000
5 -100 -100
1 15 15
2 36 36.2500000000000
3 58 57.5000000000000
4 79 78.7500000000000
5 100 100
1 100 100
2 91 91.1000000000000
3 82 82.2000000000000
4 73 73.3000000000000
5 64 64.4000000000000
6 55 55.5000000000000
7 47 46.6000000000000
8 38 37.7000000000000
9 29 28.8000000000000
10 20 19.9000000000000
11 11 11
1 100 100
2 90 90.1111111111111
3 80 80.2222222222222
4 70 70.3333333333333
5 60 60.4444444444445
6 51 50.5555555555556
7 41 40.6666666666667
8 31 30.7777777777778
9 21 20.8888888888889
10 11 11
This is an update to a question I posted before. I've gotten a little farther into this but need help with a new problem.
I'm working on a shell script right now. I need to loop through a text file, grab the text from it, and find the average number, max number and min number from each line of numbers then print them in a chart with the name of each line. This is the text file:
Experiment1 9 8 1 2 9 0 2 3 4 5
collect1 83 39 84 2 1 3 0 9
jump1 82 -1 9 26 8 9
exp2 22 0 7 1 0 7 3 2
jump2 88 7 6 5
taker1 5 5 44 2 3
This is my code so far. It should be working but it won't do any of the calculations. First loop grabs the line of text, second loop separates the name from the numbers, these two work. tHe thrid loop takes the numbers and does the calculations. It keeps giving me an error saying "expr: non integer argument", why is it doing that? I shouldn't
#!/bin/bash
while read line
do
echo $line | while read first second
do
echo $first
echo $second
sum=0
max=0
min=0
len=0
for arg in $second
do
sum=`expr $sum + $arg`
if [ $min > $arg ]
then
set min=$arg
fi
if [ $max < $arg ]
then
set max=$arg
fi
len=`expr $len + 1`
done
avg=`expr $sum / $len`
echo $avg
echo $min
echo $max
done
done < mystats.txt
This is the desired output when you type "bash statcalc.sh -s name mystats.txt"
Experiment Name Average Max Min
collect1 27 84 0
exp2 5 22 0
Experiment1 3 9 0
jump1 21 82 -1
jump2 31 88 5
taker1 13 44 2
Using awk
awk '{if (NR==1)print "Experiment Name Average Max Min"; min=$2;max=$2;for(i=2;i<=NF;i++) {a[$1]=a[$1]+$i; if (min<$i) min=$i; if(max>$i)max=$i} print $1, int(a[$1]/(NF-1)),min,max}'
Demo :
$awk '{if (NR==1)print "Experiment Name Average Max Min"; min=$2;max=$2;for(i=2;i<=NF;i++) {a[$1]=a[$1]+$i; if (min<$i) min=$i; if(max>$i)max=$i} print $1, int(a[$1]/(NF-1)),min,max}' file.txt | column -t
Experiment Name Average Max Min
Experiment1 4 9 0
collect1 27 84 0
jump1 22 82 -1
exp2 5 22 0
jump2 26 88 5
taker1 11 44 2
$cat file.txt
Experiment1 9 8 1 2 9 0 2 3 4 5
collect1 83 39 84 2 1 3 0 9
jump1 82 -1 9 26 8 9
exp2 22 0 7 1 0 7 3 2
jump2 88 7 6 5
taker1 5 5 44 2 3
$
How do I change the code if I have more than two columns. Let's say the data is like this
ifile.dat
1 10 15
3 34 20
1 4 22
3 32 33
5 3 46
2 2 98
4 20 100
3 13 23
4 50 65
1 40 76
2 20 22
How do I achieve this?
ofile.dat
1 40 76
2 20 98
3 34 33
4 50 100
5 3 46
I mean the max of each column by comparing first column. Thanks.
Here is what I have tried(on a sample file with 13columns). But the highest value is not coming up this way.
cat input.txt | sort -k1,1 -k2,2nr -k3,3nr -k4,4nr -k5,5nr -k6,6nr -k7,7nr -k8,8nr -k9,9nr -k10,10nr -nrk11,11 -nrk12,12 -nrk13,13 | sort -k1,1 -u
Instead of relying on sort, you could switch over to something more robust like awk:
awk 'BEGIN{PROCINFO["sorted_in"] = "#val_num_asc"} {for(i=2;i<=NF;++i) if (a[$1][i]<$i){a[$1][i]=$i}} END{n=asorti(a, asorted); for(col1 in asorted){print col1, a[col1][2], a[col1][3]}}' input.txt
That's a mouthful. It breaks down like:
Before processing the file set the PROCINFO setting of sorted_in to #val_num_asc since we will be sorting the contents of an array by its index which will be numeric: (BEGIN{PROCINFO["sorted_in"] = "#val_num_asc"})
Loop through each field in the record for(i=2;i<=NF;++i)
Test to see if the current value is greater than the stored value in the array which has as its index the first field's value. If it is greater, then store it in place of whatever is currently held in the array for that index at that fields position: (if (a[$1][i]<$i){a[$1][i]=$i})
When done processing all of the records, sort the array into new array asorted: (END{n=asorti(a, asorted);)
Iterate through the array and print each element (for(col1 in asorted){print col1, a[col1][2], a[col1][3]})
There may be a more elegant way to do this in awk, but this will do the trick.
Example:
:~$ cat test
1 10 15
3 34 20
1 4 22
3 32 33
5 3 46
2 2 98
4 20 100
3 13 23
4 50 65
1 40 76
2 20 22
:~$ awk 'BEGIN{PROCINFO["sorted_in"] = "#val_num_asc"} {for(i=2;i<=NF;++i) if (a[$1][i]<$i){a[$1][i]=$i}} END{n=asorti(a, asorted); for(col1 in asorted){print col1, a[col1][2], a[col1][3]}}' test
1 40 76
2 20 98
3 34 33
4 50 100
5 3 46
I have a list like the below:
1 . Fred 1 6 78 8 09
1 1 Geni 1 4 68 9 34
2 . Sam 3 4 56 6 89
3 . Flit 2 4 56 8 34
3 4 Dog 2 5 67 8 78
3 . Pig 2 5 67 2 21
(except the real list is 40 million lines long).
There are repeated elements in the second column (i.e. the ".")
I want to replace these with unique identifers (e.g. ".1", ".2", ".3"...".n")
I tried to do this with a bash loop / sed combination, but it didn't work...
Failed attempt:
for i in 1..4
do
sed -i "s_//._//."$i"_"$i""
done
(Essentially, I was trying to get sed to replace each n th "." with ".n", but this didn't work).
Here's a way to do it with awk (assuming your file is called input:
$ awk '$2=="."{$2="."++counter}{print}' input
1 .1 Fred 1 6 78 8 09
1 1 Geni 1 4 68 9 34
2 .2 Sam 3 4 56 6 89
3 .3 Flit 2 4 56 8 34
3 4 Dog 2 5 67 8 78
3 .4 Pig 2 5 67 2 21
The awk program replaces the second column ($2) by a string formed by concatenating . and a pre-incremented counter (++counter) if the second column was exactly .. It then prints out all the columns it got (with $2 modified or not) ({print}).
Plain bash alternative:
c=1
while read -r a b line ; do
if [ "$b" == "." ] ; then
echo "$a ."$((c++))" $line"
else
echo "$a $b $line"
fi
done < input
Since your question is tagged sed and bash, here are a few examples for completeness.
Bash only
Use parameter expansion. The second column will be unique, but not sequential:
i=1; while read line; do echo ${line/\./.$((i++))}; done < input
1 .1 Fred 1 6 78 8 09
1 1 Geni 1 4 68 9 34
2 .3 Sam 3 4 56 6 89
3 .4 Flit 2 4 56 8 34
3 4 Dog 2 5 67 8 78
3 .6 Pig 2 5 67 2 21
Bash + sed
sed cannot increment variables, it has to be done externally.
For each line, increment $i if line contains a ., then let sed append $i after the .
i=0
while read line; do
[[ $line == *.* ]] && i=$((i+1))
sed "s#\.#.$i#" <<<"$line"
done < input
Output:
1 .1 Fred 1 6 78 8 09
1 1 Geni 1 4 68 9 34
2 .2 Sam 3 4 56 6 89
3 .3 Flit 2 4 56 8 34
3 4 Dog 2 5 67 8 78
3 .4 Pig 2 5 67 2 21
you can use this command:
awk '{gsub(/\./,c++);print}' filename
Output:
1 0 Fred 1 6 78 8 09
1 1 Geni 1 4 68 9 34
2 2 Sam 3 4 56 6 89
3 3 Flit 2 4 56 8 34
3 4 Dog 2 5 67 8 78
3 5 Pig 2 5 67 2 21
I've a question extending the code in this question: Can you multiply two variable ranges in Bash using brace expansion (not seq) and not using loops?
This is what I've tried so far
Work out how variable boundary ranges work (finally, a good use of eval):
$ echo {1..10}
1 2 3 4 5 6 7 8 9 10
$ boundary=10
$ echo {1..$boundary}
{1..10}
$ eval echo {1..$boundary}
1 2 3 4 5 6 7 8 9 10
But how can you multiply two variable boundary ranges?
$ echo $(({1..10}*{1..10}))
1 2 3 4 5 6 7 8 9 10 2 4 6 8 10 12 14 16 18 20 3 6 9 12 15 18 21 24 27 30 4 8 12 16 20 24 28 32 36 40 5 10 15 20 25 30 35 40 45 50 6 12 18 24 30 36 42 48 54 60 7 14 21 28 35 42 49 56 63 70 8 16 24 32 40 48 56 64 72 80 9 18 27 36 45 54 63 72 81 90 10 20 30 40 50 60 70 80 90 100
$ boundary=10
$ echo $(({1..$boundary}*{1..$boundary}))
bash: {1..10}*{1..10}: syntax error: operand expected (error token is "{1..10}*{1..10}")
$ eval echo $(({1..$boundary}*{1..$boundary}))
bash: {1..10}*{1..10}: syntax error: operand expected (error token is "{1..10}*{1..10}")
this seems to work, just escaped the $ and [] to delay their evaluation (so that they are echoed, then evaluated)
eval echo \$\[{1..$boundary}*{1..$boundary}\]
That said I now need to go lookup what $[] does ;-)
Second answer, with non deprecated $[] syntax (but two evals)
eval eval echo "\$\(\("{1..$boundary}*{1..$boundary}"\)\)"
or
eval eval echo \\\$\\\(\\\({1..$boundary}*{1..$boundary}\\\)\\\)