Choose random string from a few and set it as a variable?
0
I have a few strings, and I want to set a variable to one of them, randomly. Say the strings are test001, test002, test003 and test004.
If I set it like normal I'd obviously do it like this:
test=test001
But I want it to choose a random one from the for strings I have. I know I could do something like this, which I have done previously, but that was when choosing a random file from a directory:
test="$(printf "%sn" "${teststrings[RANDOM % ${#teststrings[@]}]}")"
But in this case I am not sure how to set testrings.
bash variable
asked Nov 4 '15 at 14:34
DisplayNameDisplayName
4,63594782
bumped to the homepage by Community♦ 3 mins ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
add a comment |
0
I have a few strings, and I want to set a variable to one of them, randomly. Say the strings are test001, test002, test003 and test004.
If I set it like normal I'd obviously do it like this:
test=test001
But I want it to choose a random one from the for strings I have. I know I could do something like this, which I have done previously, but that was when choosing a random file from a directory:
test="$(printf "%sn" "${teststrings[RANDOM % ${#teststrings[@]}]}")"
But in this case I am not sure how to set testrings.
bash variable
asked Nov 4 '15 at 14:34
DisplayNameDisplayName
4,63594782
bumped to the homepage by Community♦ 3 mins ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
set the teststrings array like this:teststrings=( test001 test002 test003 test004 ), then your code will work. To save running in a subshell,printf -v test "%sn" "${teststrings[RANDOM % ${#teststrings[@]}]}"
– glenn jackman
Nov 4 '15 at 15:01
add a comment |
0
0
0
I have a few strings, and I want to set a variable to one of them, randomly. Say the strings are test001, test002, test003 and test004.
If I set it like normal I'd obviously do it like this:
test=test001
But I want it to choose a random one from the for strings I have. I know I could do something like this, which I have done previously, but that was when choosing a random file from a directory:
test="$(printf "%sn" "${teststrings[RANDOM % ${#teststrings[@]}]}")"
But in this case I am not sure how to set testrings.
bash variable
asked Nov 4 '15 at 14:34
DisplayNameDisplayName
4,63594782
I have a few strings, and I want to set a variable to one of them, randomly. Say the strings are test001, test002, test003 and test004.
If I set it like normal I'd obviously do it like this:
test=test001
But I want it to choose a random one from the for strings I have. I know I could do something like this, which I have done previously, but that was when choosing a random file from a directory:
test="$(printf "%sn" "${teststrings[RANDOM % ${#teststrings[@]}]}")"
But in this case I am not sure how to set testrings.
bash variable
bash variable
asked Nov 4 '15 at 14:34
DisplayNameDisplayName
4,63594782
asked Nov 4 '15 at 14:34
DisplayNameDisplayName
4,63594782
edited Nov 4 '15 at 14:49
DisplayName
asked Nov 4 '15 at 14:34
DisplayNameDisplayName
4,63594782
asked Nov 4 '15 at 14:34
DisplayNameDisplayName
4,63594782
asked Nov 4 '15 at 14:34
DisplayNameDisplayName
4,63594782
4,63594782
bumped to the homepage by Community♦ 3 mins ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
bumped to the homepage by Community♦ 3 mins ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
set the teststrings array like this:teststrings=( test001 test002 test003 test004 ), then your code will work. To save running in a subshell,printf -v test "%sn" "${teststrings[RANDOM % ${#teststrings[@]}]}"
– glenn jackman
Nov 4 '15 at 15:01
add a comment |
set the teststrings array like this:teststrings=( test001 test002 test003 test004 ), then your code will work. To save running in a subshell,printf -v test "%sn" "${teststrings[RANDOM % ${#teststrings[@]}]}"
– glenn jackman
Nov 4 '15 at 15:01
set the teststrings array like this:
teststrings=( test001 test002 test003 test004 ), then your code will work. To save running in a subshell, printf -v test "%sn" "${teststrings[RANDOM % ${#teststrings[@]}]}"– glenn jackman
Nov 4 '15 at 15:01
set the teststrings array like this:
teststrings=( test001 test002 test003 test004 ), then your code will work. To save running in a subshell, printf -v test "%sn" "${teststrings[RANDOM % ${#teststrings[@]}]}"– glenn jackman
Nov 4 '15 at 15:01
add a comment |
2 Answers
2
active
oldest
votes
0
You can still do something similar:
v=$(printf "test%03d" $(($RANDOM%4+1)))
v=${!v}
where bash ${!variable} does one level of indirection towards the real variable test001 etc.
When the names of the variables can be anything, eg test001 somevar anothervar, setup an array:
declare -a teststrings=(test001 somevar anothervar)
v=${teststrings[$(($RANDOM % ${#teststrings[*]}))]}
w=${!v}
echo $w
answered Nov 4 '15 at 14:46
meuhmeuh
32.5k12154
Good answer, but unfortunetaly I might have written my question a bit wrong. The strings can be anything, not just the same thing with increasing numbers. Sorry.
– DisplayName
Nov 4 '15 at 14:54
can you put all the variable names in an array?
– meuh
Nov 4 '15 at 14:58
add a comment |
0
array=(test001 test002 test003 test004)
totalstr=$((${#array[@]} - 1)) # -1 because 1st string = ${array[0]} , and last one(4th) = ${array[3]
randomnum=$(($(($RANDOM % $totalstr)) + 0)) # get random number between 0 and $totalstr-1
your_random_var=$(echo ${array[$randomnum]})
answered Nov 4 '15 at 15:08
JonasJonas
903517
That method to count how many elements the array has will break if any element contains whitespace, or if there are glob-patterns that match files. Simply usetotalstr=${#array[@]}.
– glenn jackman
Nov 4 '15 at 15:58
You don't need to nest arithmetic expressions:$(( (RANDOM % totalstr) + 0 ))will do, but you don't need to add zero: why do you do that?
– glenn jackman
Nov 4 '15 at 15:58
Thanks , I d no idea about the array count, that's why ... !
– Jonas
Nov 4 '15 at 18:26
the '-1' & '+ 0' in both cmds , because the array starts from 0 , ends in totalstr-1 , if not , we won(t be able to call the first string inside the array , and we will call the empty one ${array[4]} as in this example !
– Jonas
Nov 5 '15 at 13:38
add a comment |
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2 Answers
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active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
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oldest
votes
0
You can still do something similar:
v=$(printf "test%03d" $(($RANDOM%4+1)))
v=${!v}
where bash ${!variable} does one level of indirection towards the real variable test001 etc.
When the names of the variables can be anything, eg test001 somevar anothervar, setup an array:
declare -a teststrings=(test001 somevar anothervar)
v=${teststrings[$(($RANDOM % ${#teststrings[*]}))]}
w=${!v}
echo $w
answered Nov 4 '15 at 14:46
meuhmeuh
32.5k12154
Good answer, but unfortunetaly I might have written my question a bit wrong. The strings can be anything, not just the same thing with increasing numbers. Sorry.
– DisplayName
Nov 4 '15 at 14:54
can you put all the variable names in an array?
– meuh
Nov 4 '15 at 14:58
add a comment |
0
You can still do something similar:
v=$(printf "test%03d" $(($RANDOM%4+1)))
v=${!v}
where bash ${!variable} does one level of indirection towards the real variable test001 etc.
When the names of the variables can be anything, eg test001 somevar anothervar, setup an array:
declare -a teststrings=(test001 somevar anothervar)
v=${teststrings[$(($RANDOM % ${#teststrings[*]}))]}
w=${!v}
echo $w
answered Nov 4 '15 at 14:46
meuhmeuh
32.5k12154
Good answer, but unfortunetaly I might have written my question a bit wrong. The strings can be anything, not just the same thing with increasing numbers. Sorry.
– DisplayName
Nov 4 '15 at 14:54
can you put all the variable names in an array?
– meuh
Nov 4 '15 at 14:58
add a comment |
0
0
0
You can still do something similar:
v=$(printf "test%03d" $(($RANDOM%4+1)))
v=${!v}
where bash ${!variable} does one level of indirection towards the real variable test001 etc.
When the names of the variables can be anything, eg test001 somevar anothervar, setup an array:
declare -a teststrings=(test001 somevar anothervar)
v=${teststrings[$(($RANDOM % ${#teststrings[*]}))]}
w=${!v}
echo $w
answered Nov 4 '15 at 14:46
meuhmeuh
32.5k12154
You can still do something similar:
v=$(printf "test%03d" $(($RANDOM%4+1)))
v=${!v}
where bash ${!variable} does one level of indirection towards the real variable test001 etc.
When the names of the variables can be anything, eg test001 somevar anothervar, setup an array:
declare -a teststrings=(test001 somevar anothervar)
v=${teststrings[$(($RANDOM % ${#teststrings[*]}))]}
w=${!v}
echo $w
answered Nov 4 '15 at 14:46
meuhmeuh
32.5k12154
edited Nov 4 '15 at 15:06
answered Nov 4 '15 at 14:46
meuhmeuh
32.5k12154
answered Nov 4 '15 at 14:46
meuhmeuh
32.5k12154
answered Nov 4 '15 at 14:46
meuhmeuh
32.5k12154
32.5k12154
Good answer, but unfortunetaly I might have written my question a bit wrong. The strings can be anything, not just the same thing with increasing numbers. Sorry.
– DisplayName
Nov 4 '15 at 14:54
can you put all the variable names in an array?
– meuh
Nov 4 '15 at 14:58
add a comment |
Good answer, but unfortunetaly I might have written my question a bit wrong. The strings can be anything, not just the same thing with increasing numbers. Sorry.
– DisplayName
Nov 4 '15 at 14:54
can you put all the variable names in an array?
– meuh
Nov 4 '15 at 14:58
Good answer, but unfortunetaly I might have written my question a bit wrong. The strings can be anything, not just the same thing with increasing numbers. Sorry.
– DisplayName
Nov 4 '15 at 14:54
Good answer, but unfortunetaly I might have written my question a bit wrong. The strings can be anything, not just the same thing with increasing numbers. Sorry.
– DisplayName
Nov 4 '15 at 14:54
can you put all the variable names in an array?
– meuh
Nov 4 '15 at 14:58
can you put all the variable names in an array?
– meuh
Nov 4 '15 at 14:58
add a comment |
0
array=(test001 test002 test003 test004)
totalstr=$((${#array[@]} - 1)) # -1 because 1st string = ${array[0]} , and last one(4th) = ${array[3]
randomnum=$(($(($RANDOM % $totalstr)) + 0)) # get random number between 0 and $totalstr-1
your_random_var=$(echo ${array[$randomnum]})
answered Nov 4 '15 at 15:08
JonasJonas
903517
That method to count how many elements the array has will break if any element contains whitespace, or if there are glob-patterns that match files. Simply usetotalstr=${#array[@]}.
– glenn jackman
Nov 4 '15 at 15:58
You don't need to nest arithmetic expressions:$(( (RANDOM % totalstr) + 0 ))will do, but you don't need to add zero: why do you do that?
– glenn jackman
Nov 4 '15 at 15:58
Thanks , I d no idea about the array count, that's why ... !
– Jonas
Nov 4 '15 at 18:26
the '-1' & '+ 0' in both cmds , because the array starts from 0 , ends in totalstr-1 , if not , we won(t be able to call the first string inside the array , and we will call the empty one ${array[4]} as in this example !
– Jonas
Nov 5 '15 at 13:38
add a comment |
0
array=(test001 test002 test003 test004)
totalstr=$((${#array[@]} - 1)) # -1 because 1st string = ${array[0]} , and last one(4th) = ${array[3]
randomnum=$(($(($RANDOM % $totalstr)) + 0)) # get random number between 0 and $totalstr-1
your_random_var=$(echo ${array[$randomnum]})
answered Nov 4 '15 at 15:08
JonasJonas
903517
That method to count how many elements the array has will break if any element contains whitespace, or if there are glob-patterns that match files. Simply usetotalstr=${#array[@]}.
– glenn jackman
Nov 4 '15 at 15:58
You don't need to nest arithmetic expressions:$(( (RANDOM % totalstr) + 0 ))will do, but you don't need to add zero: why do you do that?
– glenn jackman
Nov 4 '15 at 15:58
Thanks , I d no idea about the array count, that's why ... !
– Jonas
Nov 4 '15 at 18:26
the '-1' & '+ 0' in both cmds , because the array starts from 0 , ends in totalstr-1 , if not , we won(t be able to call the first string inside the array , and we will call the empty one ${array[4]} as in this example !
– Jonas
Nov 5 '15 at 13:38
add a comment |
0
0
0
array=(test001 test002 test003 test004)
totalstr=$((${#array[@]} - 1)) # -1 because 1st string = ${array[0]} , and last one(4th) = ${array[3]
randomnum=$(($(($RANDOM % $totalstr)) + 0)) # get random number between 0 and $totalstr-1
your_random_var=$(echo ${array[$randomnum]})
answered Nov 4 '15 at 15:08
JonasJonas
903517
array=(test001 test002 test003 test004)
totalstr=$((${#array[@]} - 1)) # -1 because 1st string = ${array[0]} , and last one(4th) = ${array[3]
randomnum=$(($(($RANDOM % $totalstr)) + 0)) # get random number between 0 and $totalstr-1
your_random_var=$(echo ${array[$randomnum]})
answered Nov 4 '15 at 15:08
JonasJonas
903517
edited Nov 5 '15 at 13:15
answered Nov 4 '15 at 15:08
JonasJonas
903517
answered Nov 4 '15 at 15:08
JonasJonas
903517
answered Nov 4 '15 at 15:08
JonasJonas
903517
903517
That method to count how many elements the array has will break if any element contains whitespace, or if there are glob-patterns that match files. Simply usetotalstr=${#array[@]}.
– glenn jackman
Nov 4 '15 at 15:58
You don't need to nest arithmetic expressions:$(( (RANDOM % totalstr) + 0 ))will do, but you don't need to add zero: why do you do that?
– glenn jackman
Nov 4 '15 at 15:58
Thanks , I d no idea about the array count, that's why ... !
– Jonas
Nov 4 '15 at 18:26
the '-1' & '+ 0' in both cmds , because the array starts from 0 , ends in totalstr-1 , if not , we won(t be able to call the first string inside the array , and we will call the empty one ${array[4]} as in this example !
– Jonas
Nov 5 '15 at 13:38
add a comment |
That method to count how many elements the array has will break if any element contains whitespace, or if there are glob-patterns that match files. Simply usetotalstr=${#array[@]}.
– glenn jackman
Nov 4 '15 at 15:58
You don't need to nest arithmetic expressions:$(( (RANDOM % totalstr) + 0 ))will do, but you don't need to add zero: why do you do that?
– glenn jackman
Nov 4 '15 at 15:58
Thanks , I d no idea about the array count, that's why ... !
– Jonas
Nov 4 '15 at 18:26
the '-1' & '+ 0' in both cmds , because the array starts from 0 , ends in totalstr-1 , if not , we won(t be able to call the first string inside the array , and we will call the empty one ${array[4]} as in this example !
– Jonas
Nov 5 '15 at 13:38
That method to count how many elements the array has will break if any element contains whitespace, or if there are glob-patterns that match files. Simply use
totalstr=${#array[@]}.– glenn jackman
Nov 4 '15 at 15:58
That method to count how many elements the array has will break if any element contains whitespace, or if there are glob-patterns that match files. Simply use
totalstr=${#array[@]}.– glenn jackman
Nov 4 '15 at 15:58
You don't need to nest arithmetic expressions:
$(( (RANDOM % totalstr) + 0 )) will do, but you don't need to add zero: why do you do that?– glenn jackman
Nov 4 '15 at 15:58
You don't need to nest arithmetic expressions:
$(( (RANDOM % totalstr) + 0 )) will do, but you don't need to add zero: why do you do that?– glenn jackman
Nov 4 '15 at 15:58
Thanks , I d no idea about the array count, that's why ... !
– Jonas
Nov 4 '15 at 18:26
Thanks , I d no idea about the array count, that's why ... !
– Jonas
Nov 4 '15 at 18:26
the '-1' & '+ 0' in both cmds , because the array starts from 0 , ends in totalstr-1 , if not , we won(t be able to call the first string inside the array , and we will call the empty one ${array[4]} as in this example !
– Jonas
Nov 5 '15 at 13:38
the '-1' & '+ 0' in both cmds , because the array starts from 0 , ends in totalstr-1 , if not , we won(t be able to call the first string inside the array , and we will call the empty one ${array[4]} as in this example !
– Jonas
Nov 5 '15 at 13:38
add a comment |
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set the teststrings array like this:
teststrings=( test001 test002 test003 test004 ), then your code will work. To save running in a subshell,printf -v test "%sn" "${teststrings[RANDOM % ${#teststrings[@]}]}"– glenn jackman
Nov 4 '15 at 15:01