# Comparing Arays

Discussion in 'Perl Misc' started by Taxi Driver, Sep 18, 2005.

1. ### Taxi DriverGuest

Hi Everyone -
Can I get your help with this, it is driving me crazy.
I have 2 arrays listed below:
@req[0][0]=75
@req[1][0]=76
@req[2][0]=77
@req[2][0]=78
---
@bid[0][0]=75
@bid[1][0]=76
@bid[2][0]=80

I need to find all cases where a number in @req is NOT in @bid. In
this example 77 and 78.

Thank you

Taxi Driver, Sep 18, 2005

2. ### Matt GarrishGuest

"Taxi Driver" <> wrote in message
news:...
> Hi Everyone -
> Can I get your help with this, it is driving me crazy.
> I have 2 arrays listed below:
> @req[0][0]=75

What are these things? Did you mean to write \$req[0][0]? If so, please bear
in mind that you should always post real code.

> @req[1][0]=76
> @req[2][0]=77
> @req[2][0]=78

Why are you using multi-dimensional arrays when there is only one entry for
each? Or are there more entries? It's hard to give you useful help if you
don't present the problem clearly (like why you repeated @req[2][0], for
example).

> ---
> @bid[0][0]=75
> @bid[1][0]=76
> @bid[2][0]=80
>
> I need to find all cases where a number in @req is NOT in @bid. In
> this example 77 and 78.
>

Hashes are your friend in situations like this. Assuming you have a real
mutlidimensional array (and all the entries in @bid and @req contain
references to arrays):

my %chk;

for my \$x (0..\$#bid) {
for my \$y (0..\$#{\$bid[\$x]}) {
\$chk{\$bid[\$x][\$y]} = 1;
}
}

for my \$i (0..\$#req) {
for my \$j (0..\$#{\$req[\$i]}) {
}
}

Matt

Matt Garrish, Sep 18, 2005

3. ### John BokmaGuest

Taxi Driver <> wrote:

> Hi Everyone -
> Can I get your help with this, it is driving me crazy.
> I have 2 arrays listed below:
> @req[0][0]=75
> @req[1][0]=76
> @req[2][0]=77
> @req[2][0]=78
> ---
> @bid[0][0]=75
> @bid[1][0]=76
> @bid[2][0]=80

Uhm...

You mean:

use strict;
use warnings;

my @req = ( 75 .. 78 );
my @bid = ( 75, 76, 80 );

> I need to find all cases where a number in @req is NOT in @bid. In
> this example 77 and 78.

my %test;
@test{ @bid } = ();

my @not_in;
exists \$test{ \$_ } or push @not_in, \$_ for @req;

print join( ', ', @not_in ), "\n";

--
John Small Perl scripts: http://johnbokma.com/perl/
Perl programmer available: http://castleamber.com/
Happy Customers: http://castleamber.com/testimonials.html

John Bokma, Sep 18, 2005
4. ### Taxi DriverGuest

Thank you. That is exactly what I was looking for.
I apologize for not posting code.

TD

Matt Garrish:
"Matt Garrish" <> a écrit dans le
message :
>
>"Taxi Driver" <> wrote in message
>news:...
>> Hi Everyone -
>> Can I get your help with this, it is driving me crazy.
>> I have 2 arrays listed below:
>> @req[0][0]=75

>
>What are these things? Did you mean to write \$req[0][0]? If so, please bear
>in mind that you should always post real code.
>
>> @req[1][0]=76
>> @req[2][0]=77
>> @req[2][0]=78

>
>Why are you using multi-dimensional arrays when there is only one entry for
>each? Or are there more entries? It's hard to give you useful help if you
>don't present the problem clearly (like why you repeated @req[2][0], for
>example).
>
>> ---
>> @bid[0][0]=75
>> @bid[1][0]=76
>> @bid[2][0]=80
>>
>> I need to find all cases where a number in @req is NOT in @bid. In
>> this example 77 and 78.
>>

>
>Hashes are your friend in situations like this. Assuming you have a real
>mutlidimensional array (and all the entries in @bid and @req contain
>references to arrays):
>
>my %chk;
>
>for my \$x (0..\$#bid) {
> for my \$y (0..\$#{\$bid[\$x]}) {
> \$chk{\$bid[\$x][\$y]} = 1;
> }
>}
>
>for my \$i (0..\$#req) {
> for my \$j (0..\$#{\$req[\$i]}) {
> }
>}
>
>
>Matt
>

Taxi Driver, Sep 18, 2005
5. ### Taxi DriverGuest

It all works great until I added a second variable (ts) to the first
MYSQL Select statement. Then I get multiple valuse for ts instead of
one.
---------------
#!/usr/bin/perl
use DBI;
#Declare arrays to hold results
my @data;
my @data2;
my (@requests) = ();
my (@bids) = ();

# Database information
\$db="X";
\$host="X";
\$port="X";
\$userid="X";
\$passwd="X";
\$connectionInfo="DBI:mysql:database=\$db;\$host:\$port";

# Make connection to database
\$dbh = DBI->connect(\$connectionInfo,\$userid,\$passwd) or die "Couldn't
connect to db. " . \$sth->errstr;

# Prepare and execute query
\$query = "SELECT id, ts FROM insrequest WHERE status=0 ORDER BY id";
\$sth = \$dbh->prepare(\$query);
\$sth->execute()or die "Couldn't execute statement. " . \$sth->errstr;

# Read the matching records and print them out.
while (@data = \$sth->fetchrow_array()) {
my \$id = \$data[0];
push(@requests, [@data]);
# print "Row: @data\n";
}

if (\$sth->rows == 0) {
print "No jobs found.\n\n";
}

# Second query
\$query2 = "SELECT DISTINCT jobnum FROM insbid1 ORDER BY jobnum";
\$sth = \$dbh->prepare(\$query2);
\$sth->execute()or die "Couldn't execute statement. " . \$sth->errstr;

# Read the matching records and print them out.
while (@data2 = \$sth->fetchrow_array()) {
my \$jobnum = \$data2[0];
push(@bids, [@data2]);
}

if (\$sth->rows == 0) {
print "No bids found insbid1.\n\n";
}

\$sth->finish();

# Disconnect from database
\$dbh->disconnect;

# Comparison
my %chk;

for my \$x (0..\$#bids) {
for my \$y (0..\$#{\$bids[\$x]}) {
\$chk{\$bids[\$x][\$y]} = 1;
}
}

for my \$i (0..\$#requests) {
for my \$j (0..\$#{\$requests[\$i]}) {
print "\t\$requests[\$i][\$j]\n" unless \$chk{\$requests[\$i][\$j]};
}
}
----------
Matt Garrish:
"Matt Garrish" <> a écrit dans le
message :
>
>"Taxi Driver" <> wrote in message
>news:...
>> Hi Everyone -
>> Can I get your help with this, it is driving me crazy.
>> I have 2 arrays listed below:
>> @req[0][0]=75

>
>What are these things? Did you mean to write \$req[0][0]? If so, please bear
>in mind that you should always post real code.
>
>> @req[1][0]=76
>> @req[2][0]=77
>> @req[2][0]=78

>
>Why are you using multi-dimensional arrays when there is only one entry for
>each? Or are there more entries? It's hard to give you useful help if you
>don't present the problem clearly (like why you repeated @req[2][0], for
>example).
>
>> ---
>> @bid[0][0]=75
>> @bid[1][0]=76
>> @bid[2][0]=80
>>
>> I need to find all cases where a number in @req is NOT in @bid. In
>> this example 77 and 78.
>>

>
>Hashes are your friend in situations like this. Assuming you have a real
>mutlidimensional array (and all the entries in @bid and @req contain
>references to arrays):
>
>my %chk;
>
>for my \$x (0..\$#bid) {
> for my \$y (0..\$#{\$bid[\$x]}) {
> \$chk{\$bid[\$x][\$y]} = 1;
> }
>}
>
>for my \$i (0..\$#req) {
> for my \$j (0..\$#{\$req[\$i]}) {
> }
>}
>
>
>Matt
>

Taxi Driver, Sep 18, 2005
6. ### John BokmaGuest

Taxi Driver <> wrote:

> It all works great until I added a second variable (ts) to the first
> MYSQL Select statement. Then I get multiple valuse for ts instead of
> one.
> ---------------
> #!/usr/bin/perl
> use DBI;

most people stop looking now, because you forgot use strict; and use
warnings;

Also, it looks like you are attempting to program a join in Perl, instead
of using the database to do this. Try to give an exact description of your
problem based on the database table(s), I am sure it can be done in SQL.

Finally, *don't* top post.

--
John Small Perl scripts: http://johnbokma.com/perl/
Perl programmer available: http://castleamber.com/
Happy Customers: http://castleamber.com/testimonials.html

John Bokma, Sep 18, 2005
7. ### William JamesGuest

John Bokma wrote:
> Taxi Driver <> wrote:
>
> > Hi Everyone -
> > Can I get your help with this, it is driving me crazy.
> > I have 2 arrays listed below:
> > @req[0][0]=75
> > @req[1][0]=76
> > @req[2][0]=77
> > @req[2][0]=78
> > ---
> > @bid[0][0]=75
> > @bid[1][0]=76
> > @bid[2][0]=80

>
> Uhm...
>
> You mean:
>
> use strict;
> use warnings;
>
> my @req = ( 75 .. 78 );
> my @bid = ( 75, 76, 80 );
>
> > I need to find all cases where a number in @req is NOT in @bid. In
> > this example 77 and 78.

>
> my %test;
> @test{ @bid } = ();
>
> my @not_in;
> exists \$test{ \$_ } or push @not_in, \$_ for @req;
>
> print join( ', ', @not_in ), "\n";

In Ruby:

req = ( 75 .. 78 ).to_a
bid = [ 75, 76, 80 ]
p req - bid

William James, Sep 18, 2005