Re: Convert ASCII string to 7-bit binary string

c:\@Work\Perl\monks>perl -wMstrict -le
"my $out;
 ;;
 $out .= reverse for unpack '(b7)*', '4B3A';
 print qq{'$out'};
"
'0110100100001001100111000001'
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Re^2: Convert ASCII string to 7-bit binary string by johngg (Canon) on Oct 28, 2015 at 11:52 UTC
A slight variant that unpacks in the right order and drops the reverse for the expense of a second unpack inside a map. `$ perl -Mstrict -Mwarnings -E ' my $out; $out .= $_ for map { unpack q{xA7}, $_ } unpack q{(B8)*}, q{4B3A}; say $out;' 0110100100001001100111000001 $` [download] Not as succinct but possibly slightly easier to work out what is going on because it is not immediately clear that your `b7` format will drop the last (most significant) bit before you reverse the bits into the correct order. Cheers, JohnGG	[reply] [d/l] [select]
Re^3: Convert ASCII string to 7-bit binary string by AnomalousMonk (Archbishop) on Oct 28, 2015 at 12:55 UTC
Inspired by kennethk's second approach above, this avoids the reversible complexity of either `'(B8)'` or `'(b7)'` in favor of `'C'` simplicity: `c:\@Work\Perl\monks>perl -wMstrict -le "my $out; $out .= sprintf '%07b', $_ for unpack 'C', '4B3A'; print qq{'$out'}; " '0110100100001001100111000001'` [download] Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]
Re^2: Convert ASCII string to 7-bit binary string by Anonymous Monk on Oct 30, 2015 at 22:52 UTC
why do you reverse?	[reply]
Re^3: Convert ASCII string to 7-bit binary string by AnomalousMonk (Archbishop) on Oct 31, 2015 at 10:52 UTC
Because the `b7` unpack template that drops the most significant bit of the converted character also produces the binary digits in little-endian order. The OPer wants them in big-endian (i.e., most significant binary digit on the left) order, hence the 7-character sub-string must be reversed before being appended to the `$out` string. Try it without reverse and see what you get. Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]