CODEWITHSUNDEEP
arraysbashloops
user321627
user321627

Reputation: 2564

In Bash, how to loop over a vector of values?

I currently have 3 variables which are either set to true or false. I have 5 such scenarios:

var1 = T; var2 = T; var3 = T
var1 = T; var2 = T; var3 = F
var1 = F; var2 = T; var3 = F
var1 = F; var2 = F; var3 = T
var1 = F; var2 = F; var3 = F

I would like to create a loop in my bash script that is able to loop over each of the above 5 scenarios and set the variables accordingly. Is there a way to put everything in a matrix-like array and call them out? If I do:

for var1 in T F; do for var2 in T F; do for var3 in T F; do
# execute whatever here.....
done
done
done

It obviously goes over what I want, and if I were to scale this up to many variables and many scenarios, it becomes unfeasible. In summary, I would like have three variables set for each loop that contains the values in each of the 5 scenarios. Is there a way to program this in a bash script? thanks.

Upvotes: 1

Views: 540

Answers (2)

Mark Setchell
Mark Setchell

Reputation: 207405

Here are a few ideas...

Feed into a loop

line=1
while read var1 var2 var3; do
   echo $line: $var1, $var2, $var3
   ((line+=1))
done <<EOF
T T T
T T F
F T F
F F T
F F F
EOF

Output

1: T, T, T
2: T, T, F
3: F, T, F
4: F, F, T
5: F, F, F

Feed into a loop

line=1
cat <<EOF |
T T T
T T F
F T F
F F T
F F F
EOF

while read var1 var2 var3; do
   echo $line: $var1, $var2, $var3
   ((line+=1))
done

Output

1: T, T, T
2: T, T, F
3: F, T, F
4: F, F, T
5: F, F, F

Use a function

func(){
   var1=$1; var2=$2; var3=$3
   echo $var1, $var2, $var3
}

func 1 1 1
func 1 1 0
func 0 1 0
func 0 0 1
func 0 0 0

Output

1, 1, 1
1, 1, 0
0, 1, 0
0, 0, 1
0, 0, 0

Upvotes: 1

mirmdasif
mirmdasif

Reputation: 6354

What you are trying to achieve should be achievable by arrays

http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_10_02.html

And then declaring your scenarios in a 2d matrix and loop over it

How to declare 2D array in bash

Upvotes: 1

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