How to split a delimited string into an array in awk?

Question

How to split the string when it contains pipe symbols | in it. I want to split them to be in array.

I tried

echo "12:23:11" | awk '{split(0,ドルa,":"); print a[3] a[2] a[1]}'

Which works fine. If my string is like "12|23|11" then how do I split them into an array?

• dubiousjim: Note that your output is concatenating the array elements, with no separator. If you instead wanted them to be separated with OFS, stick commas in between them, making print see them as separate arguments.
• slushy: Or you can use sed: echo "12:23:11" | sed "s/.*://"
• Olivier Dulac: @slushy: your command is not at all what the asker needs. your command ( echo "12:23:11" | sed "s/.*://") delete everything until (and including) the last ":", keeping only the "11" ... it works to get the last number, but would need to be modified (in an difficult to read way) to get the 2nd number, etc. awk (and awk's split) is much more elegant and readable.
• ccpizza: if you need to split on a single character you can use cut
• Et7f3XIV: Just in case it is a XY problem or you are in environment without sed. input="12:23:11" and then output=$(echo -n ":${input}" | tr ':' '\n' | tac -b | tr '\n' ':'); output="${output#:}"; echo "${output}" output now contains 11:23:12

Answer 1

Have you tried:

echo "12|23|11" | awk '{split(0,ドルa,"|"); print a[3],a[2],a[1]}'

• Dimitre Radoulov: @Mohamed Saligh, if you're on Solaris, you need to use /usr/xpg4/bin/awk, given the string length.
• shellter: 'is not working for me'. especially with colons between the echoed values and split set up to split on '|'??? Typo? Good luck to all.
• Alston: Better with some syntax explanation.
• WhiteWind: This will not work in GNU awk, because third argument to split is regular expression, and | is special symbol, which needs to be escaped. Use split(0,ドル a, "\|")
• Olivier Dulac: @WhiteWind: another way to "ensure" that | is seen as a char and not a special symbol is to put it between [] : ie, split(0,ドル a, "[|]") # I like this better than '\|', in some cases, especially as some variant of regexp (perl vs grep vs .. others?) can have "|" interepreted literally and "\|" seen as regex separator, instead of the opposite... ymmv

Answer 2

To split a string to an array in awk we use the function split():

awk '{split(0,ドル array, ":")}'
# \/ \___/ \_/
# | | |
# string | delimiter
# |
# array to store the pieces

---

If no separator is given, it uses the FS, which defaults to the space:

$ awk '{split(0,ドル array); print array[2]}' <<< "a:b c:d e"
c:d

We can give a separator, for example ::

$ awk '{split(0,ドル array, ":"); print array[2]}' <<< "a:b c:d e"
b c

Which is equivalent to setting it through the FS:

$ awk -F: '{split(0,ドル array); print array[2]}' <<< "a:b c:d e"
b c

In GNU Awk you can also provide the separator as a regexp:

$ awk '{split(0,ドル array, ":*"); print array[2]}' <<< "a:::b c::d e
#note multiple :
b c

And even see what the delimiter was on every step by using its fourth parameter:

$ awk '{split(0,ドル array, ":*", sep); print array[2]; print sep[1]}' <<< "a:::b c::d e"
b c
:::

Let's quote the man page of GNU awk:

split(string, array [, fieldsep [, seps ] ])

Divide string into pieces separated by fieldsep and store the pieces in array and the separator strings in the seps array. The first piece is stored in array[1], the second piece in array[2], and so forth. The string value of the third argument, fieldsep, is a regexp describing where to split string (much as FS can be a regexp describing where to split input records). If fieldsep is omitted, the value of FS is used. split() returns the number of elements created. seps is a gawk extension, with seps[i] being the separator string between array[i] and array[i+1]. If fieldsep is a single space, then any leading whitespace goes into seps[0] and any trailing whitespace goes into seps[n], where n is the return value of split() (i.e., the number of elements in array).

Answer 3

Please be more specific! What do you mean by "it doesn't work"? Post the exact output (or error message), your OS and awk version:

% awk -F\| '{
 for (i = 0; ++i <= NF;)
 print i, $i
 }' <<<'12|23|11'
1 12
2 23
3 11

Or, using split:

% awk '{
 n = split(0,ドル t, "|")
 for (i = 0; ++i <= n;)
 print i, t[i]
 }' <<<'12|23|11'
1 12
2 23
3 11

Edit: on Solaris you'll need to use the POSIX awk (/usr/xpg4/bin/awk) in order to process 4000 fields correctly.

• PiotrNycz: for(i = 0 or for(i = 1 ?
• Dimitre Radoulov: i = 0, because I use ++i after (not i++).
• PiotrNycz: Ok - I did not notice this. I strongly believe more readable would be for (i = 1; i <= n; ++i) ...
• RARE Kpop Manifesto: @PiotrNycz @Dimitre : why not for (i = 0; i++ < n; ) { ... } - this way it combines the best of the 1-based indexing and 0-based indexing (with the freebie bonus of no longer needing the 3rd argument in the for (...;...;...) { } statement
• PiotrNycz: @rare-kpop-manifesto if this is not just a strange sense of humor, then: we have for (init; condition; increment) construct. Each of 3 parts have their well defined places in this for-loop. What is the possible benefit of placing two parts in one slot and have one slot empty? The only reason for that is to make code less readable, thus maybe avoiding being fired - because the code will be hard to maintain by someone else?

Answer 4

I do not like the echo "..." | awk ... solution as it calls unnecessary fork and execsystem calls.

I prefer a Dimitre's solution with a little twist

awk -F\| '{print 3ドル 2ドル 1ドル}' <<<'12|23|11'

Or a bit shorter version:

awk -F\| '0ドル=3ドル 2ドル 1ドル' <<<'12|23|11'

In this case the output record put together which is a true condition, so it gets printed.

In this specific case the stdin redirection can be spared with setting an awk internal variable:

awk -v T='12|23|11' 'BEGIN{split(T,a,"|");print a[3] a[2] a[1]}'

I used ksh quite a while, but in bash this could be managed by internal string manipulation. In the first case the original string is split by internal terminator. In the second case it is assumed that the string always contains digit pairs separated by a one character separator.

T='12|23|11';echo -n ${T##*|};T=${T%|*};echo ${T#*|}${T%|*}
T='12|23|11';echo ${T:6}${T:3:2}${T:0:2}

The result in all cases is

112312

• Daniel Liston: I think the end result was supposed to be the awk array variable references, regardless of the print output example given. But you missed a really easy bash case to provide your end result. T='12:23:11';echo ${T//:}
• TrueY: @DanielListon You are right! Thanks! I did not know that the trailing / can be left in this bash expression...

Answer 5

Actually awk has a feature called 'Input Field Separator Variable' link. This is how to use it. It's not really an array, but it uses the internal $ variables. For splitting a simple string it is easier.

echo "12|23|11" | awk 'BEGIN {FS="|";} { print 1,ドル 2,ドル 3ドル }'

Answer 6

Joke? :)

How about echo "12|23|11" | awk '{split(0,ドルa,"|"); print a[3] a[2] a[1]}'

This is my output:

p2> echo "12|23|11" | awk '{split(0,ドルa,"|"); print a[3] a[2] a[1]}'
112312

so I guess it's working after all..

• Mohamed Saligh: is that because of the length of the string ? since, my string length is 4000. any ideas

Answer 7

I know this is kind of old question, but I thought maybe someone like my trick. Especially since this solution not limited to a specific number of items.

# Convert to an array
_ITEMS=($(echo "12|23|11" | tr '|' '\n'))
# Output array items
for _ITEM in "${_ITEMS[@]}"; do
 echo "Item: ${_ITEM}"
done

The output will be:

Item: 12
Item: 23
Item: 11

Answer 8

echo "12|23|11" | awk '{split(0,ドルa,"|"); print a[3] a[2] a[1]}'

should work.

Answer 9

echo "12|23|11" | awk '{split(0,ドルa,"|"); print a[3] a[2] a[1]}'

Answer 10

code

awk -F"|" '{split(0,ドルa); print a[1],a[2],a[3]}' <<< '12|23|11'

output

12 23 11

• Tyler2P: Your answer could be improved by adding more information on what the code does and how it helps the OP.

Answer 11

The challenge: parse and store split strings with spaces and insert them into variables.

Solution: best and simple choice for you would be convert the strings list into array and then parse it into variables with indexes. Here's an example how you can convert and access the array.

Example: parse disk space statistics on each line:

sudo df -k | awk 'NR>1' | while read -r line; do
 #convert into array:
 array=($line)
 #variables:
 filesystem="${array[0]}"
 size="${array[1]}"
 capacity="${array[4]}"
 mountpoint="${array[5]}"
 echo "filesystem:$filesystem|size:$size|capacity:$capacity|mountpoint:$mountpoint"
done
#output:
filesystem:/dev/dsk/c0t0d0s1|size:4000|usage:40%|mountpoint:/
filesystem:/dev/dsk/c0t0d0s2|size:5000|usage:50%|mountpoint:/usr
filesystem:/proc|size:0|usage:0%|mountpoint:/proc
filesystem:mnttab|size:0|usage:0%|mountpoint:/etc/mnttab
filesystem:fd|size:1000|usage:10%|mountpoint:/dev/fd
filesystem:swap|size:9000|usage:9%|mountpoint:/var/run
filesystem:swap|size:1500|usage:15%|mountpoint:/tmp
filesystem:/dev/dsk/c0t0d0s3|size:8000|usage:80%|mountpoint:/export

Answer 12

awk -F'['|'] -v '{print 1ドル"\t"2ドル"\t"3ドル}' file <<<'12|23|11'