Package: gawk
Version: 1:4.0.1+dfsg-2.1
Severity: normal
Hello,
thanks for maintaining gawk in Debian!
I noticed that the gawk(1) man page is somewhat misleading regarding
for loops that involve multi-index arrays.
The man page says (in section "Arrays"):
[...]
| The special operator in may be used to test if an array has an index
| consisting of a particular value:
|
| if (val in array)
| print array[val]
|
| If the array has multiple subscripts, use (i, j) in array.
|
| The in construct may also be used in a for loop to iterate over all the
| elements of an array.
[...]
This made me think that I could write:
for ((i, j) in array)
print array[i, j]
Unfortunately, this does not work!
It seems that the other three possibilities work correctly:
$ gawk 'BEGIN { array[42] = "answer"; if (42 in array) print array[42]; }'
answer
$ gawk 'BEGIN { array[42] = "answer"; for (val in array) print array[val]; }'
answer
$ gawk 'BEGIN { array[4,2] = "answer"; if ((4,2) in array) print array[4,2];
}'
answer
but iterating on multi-index arrays does not:
$ gawk 'BEGIN { array[4,2] = "answer"; for ((i,j) in array) print array[i,j];
}'
gawk: cmd. line:1: BEGIN { array[4,2] = "answer"; for ((i,j) in array) print
array[i,j]; }
gawk: cmd. line:1: ^ syntax
error
The man page does not clearly explain this.
I found confirmation on this page:
http://stackoverflow.com/questions/14280877/multidimensional-arrays-in-awk
Please note that the reply also suggests a workaround for the missing
feature.
Is there any simpler or more elegant (but still portable to other AWK
implementations, such as mawk) way to iterate on multi-index arrays?
Please enhance the man page by clearly describing this unexpected
behavior and (possibly) by suggesting a workaround.
Please also forward this bug report upstream, if appropriate.
Thanks for your time!
-- System Information:
Debian Release: jessie/sid
APT prefers testing
APT policy: (800, 'testing'), (500, 'unstable')
Architecture: amd64 (x86_64)
Kernel: Linux 3.10-3-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Versions of packages gawk depends on:
ii libc6 2.17-93
ii libreadline6 6.2+dfsg-0.1
ii libsigsegv2 2.10-2
gawk recommends no packages.
Versions of packages gawk suggests:
pn gawk-doc <none>
-- no debconf information
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