1:23am
>
> Unless otherwise directed, fill in the blank.
>
> ======================================================================
> | Sigils and data types |
> ======================================================================
>
> Sigil Variable type
> ===== =============
>
> $ _____________scalar
>
> @ _____________array
>
> % _____________hash
>
> & _____________not sure
>
> * _____________typeglob
>
>
>
> ======================================================================
> | Special variables |
> ======================================================================
>
> Briefly describe (less than 10 words) the use of these variables.
>
> $0 holds name of program
>
> $1, $2, $3... value of each () in last lexical regex
>
> @ARGV array containing command line arguments to program
>
> $ARGV current file if using <> to parse argv
>
> $_ default var
>
> @_ default array (in a sub)
>
> $! last error
>
> %ENV configuration and stuff
>
>
>
> ======================================================================
> | Quotes |
> ======================================================================
>
I'm not sure what to do here...
> Syntactic
> Sugar Meaning Generic Interpolates
> ================================================================
> ____ Literal q// No
> ____ Literal qq/ Yes
>
> ____ External command execution qx// Yes
> Word list generation qw// No
>
> RE match m// Yes
> RE substitution s/// Yes
> Character translation tr/// No
> RE quote qr// Yes
>
>
>
> ======================================================================
> | open operator |
> ======================================================================
>
> Here is a Perl common idiom that requires a sucessful file
> handle creation before continuing.
>
> open PW, "/etc/passwd"
> or die "Cannot open password file: $!";
>
>
> Briefly (less than 5 words) describe its parts.
>
> 1. open
calls function open
>
> 2. PW
filehandle 'PW'
>
> 3. "/etc/passwd"
filename
>
> 4. die
exit on error
>
> 5. $!
error message to output
>
>
> ================
>
> # Open file for input.
> $data_file = "sales.ca";
>
> open DATA, "<$data_file________________" or die "Cannot open input file: $!";
>
>
>
> # Open file for output (truncate).
> $out_file = "commisions.ca";
>
> open OUT, ">$out_file________________" or die "Cannot open output file: $!";
>
>
>
> # Open file for output (append).
> $log_file = "status.log";
>
> open LOG, ">$log_file________________" or die "Cannot open log file: $!";
>
>
>
> # Open pipe for input to Perl.
> $ps_cmd = "ps -au | grep msrw";
>
> open PS, "dono..________________" or die "Cannot open status pipe: $!";
>
>
>
> # Open pipe for output from Perl.
> $lp_cmd = "nl | pr -l60 -h'my report' | lp -d pr1";
>
> open LP, "dono...________________" or die "Cannot open printer pipe: $!";
>
>
>
> ======================================================================
> | binary operators |
> ======================================================================
>
> operator string numeric
> ===========================================
>
> equal to eq____ = _____
>
> not equal to ne____ != _____
>
> less than lt____ < _____
>
> greater than gt ____ > _____
>
> less than or equal to ?? ____ <= _____
>
> greater than or equal to ?? ____ >= _____
>
> comparison cmp____ <=> _____
>
>
>
> ======================================================================
> | truth |
> ======================================================================
>
> Any value that is not false is true. What 3 values indicate
> false?
>
> numeric -- 0
>
> string -- ''
>
> other -- undef
>
>
>
> ======================================================================
> | shell interaction |
> ======================================================================
>
> Perl from shell
>
> 1. How is a perl program invoked from a shell (e.g. ksh, sh, bash)?
> call it like an executable
>
>
> Shell from Perl
> `/bin/sh`
> 1. What *quotes* are used to invoke a shell (or other executable) from
> Perl, collecting its STDOUT?
> ``
>
> 2. What *operator* is used to invoke a shell (or other executable)
> from Perl, using the same STDOUT as Perl?
> fork?
>
>
> ======================================================================
> | hygeine |
> ======================================================================
>
> 1. How do you specify the -w flag inside a Perl file?
> use warnings;
>
>
> ======================================================================
> | Array iteration |
> ======================================================================
>
> This code illustrates a c-style loop, using $i as an index variable.
>
> my $i;
> my @language = qw(Perl C VisualBasic KornShell FORTH);
> for ($i = 0; $i < @language; $i++) {
> my $lang = $language[$i];
> print "I can program in $lang.\n";
> }
>
> Create a similar loop without using $i, in a more Perlish style.
>
> my @language = qw(Perl VisualBasic KornShell FORTH);
>
> foreach my $lang ( @language ) {
> print "I can program in $lang.\n";
> }
>
>
>
> ======================================================================
> | Hash iteration |
> ======================================================================
>
>
> %aphorism = (
> roses => red,
> violets => purple,
> sugar => "sweet, like maple syrple"
> );
>
>
> Fill in the missing pieces to iterate over the hash.
>
> ==> The first blank will set $key to each of the keys of the hash
> (e.g. roses, violets, sugar).
>
> ==> The second blank will set $value appropriately.
>
>
> foreach my $key ( keys (%aphorism) ) {
>
> my $value = $aphorism{$key};
>
> print "$key...$value\n";
>
> }
>
>
>
> ======================================================================
> | command line arguments |
> ======================================================================
>
> What do the following command line arguments mean?
>
> -w warning
>
> -e one-liner
>
> -i causes <> to direct output to the origional file
>
> -p -n use the loop while (<>) {
} around your script, p has a continue, n dosen't
>
>
>
> ======================================================================
> | operators |
> ======================================================================
>
> Name that Perl operator:
>
> open________ open a file or pipe creating a filehandle
>
> close________ close a filehandle
>
> chomp________ chomp the trailing newline from a scalar string
>
that one was a bit obvious
> $#arry________ determine the length (element count) of an array
>
> read()________ read (scalar or list) from a filehandle
>
> push________ add scalar(s) to right side (high index) end of array
>
> pop________ remove scalar(s) to right side (high index) end of array
>
> unshift________ add scalar(s) to left side (low index) end of array
>
> shift________ remove scalar(s) to left side (low index) end of array
>
> reverse()________ reverse a list
>
> sort()________ sort a list
>
> keys()________ extract a list of hash keys
>
this was covered in a previous question
> values()________ extract a list of hash values
>
> delete $hash{$key}________ delete an element from a hash
>
> print________ print to a filehandle (STDOUT by default)
>
> printf________ print a formatted string to a filehandle (STDOUT by default)
>
> split('RE', $string) ________ split a string at RE into a list
>
> substr??________ join a list with a string into a string
>
> warn()________ warn user with message to STDERR
>
> die________ exit after warning user with message to STDERR
>
> return________ return from a subroutine or eval block
>
> system________ call the system
>
>
>
> ======================================================================
> | Regular Expressions |
> ======================================================================
>
> Supply the repetition quantifier for these convenience quantifiers:
>
> * {1,___}
>
> + {0__,___}
>
> ? {0__,1__}
>
>
> Briefly describe (less than 5 words) these flags
>
> /i ignore case
>
> /g repeat
>
> /x prety-printed regex
>
> /o compile once
>
>
> /====================================================================\
> | \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / |
> |==V== ==V== ==V== ==V== ==V== ==V== ==V== ==V== ==V== ==V==|
> | / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ |
> \====================================================================/
>
1:51
I'm just a little above intro to perl, but I still have a few million
things to learn.
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
