Questions tagged [scalar-context]
10 questions
9
votes
6 answers
Is there such a thing as a list in scalar context?
my $mind = ( 'a', 'little', 'confused' );
And it's because perldoc perlfaq4 explains the line above as follows (emphasis added):
Since you're assigning to a scalar, the righthand side is in scalar
context. The comma operator (yes, it's an…
Zaid
- 36,680
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5
votes
2 answers
Can the empty list be in scalar context?
There is a lie that a list in scalar context yields the last element of the list. This is a lie because (as the saying goes) you can't have a list in scalar context. What looks like a list in scalar context is really the comma operator in scalar…
Chas. Owens
- 64,182
- 22
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5
votes
2 answers
How to update navigation properties / related tables in EF?
I have an object Customer with a navigation property Days (days is a separate table which have - day_id, customer_id - FK).
mycontext.Customers.ApplyCurrentValues(cust);
mycontext.SaveChanges();
This only updated the scalar properties of Customer,…
BornToCode
- 9,495
- 9
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4
votes
4 answers
Perl "reverse comma operator" (Example from the book Programming Perl, 4th Edition)
I'm reading "Programming Perl" and ran into a strange example that does not seem to make sense. The book describes how the comma operator in Perl will return only the last result when used in a scalar context.
Example:
# After this statement,…
tjwrona1992
- 8,614
- 8
- 35
- 98
3
votes
2 answers
How does word counting by list assignment work in Perl?
I cannot exactly understand how the following snippet works:
my $str = 'abc def ghi';
my $num = () = $str =~ /\w+/g;
say $num; # prints the word count, 3
I know that $str =~ /\w+/g returns a list of the words which, apparently, is conveyed to the…
Tolga Kurt
- 85
- 1
- 6
3
votes
5 answers
Two-dimensional array access in Perl
I have an array populated with cities. I want to pass the array by reference to a sub routine and print each city to output. However, I have the following problems:
I can access each element before my while loop in the subroutine. But I cannot…
donsiuch
- 343
- 3
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- 18
1
vote
1 answer
Concatenating strings from a multidimensional array overwrites the target string in Perl
I've built a two dimension array with string values. There are always 12 columns but the number of rows vary. Now I'd like to build a string of each row but when I run the following code:
$outstring = "";
for ($i=0; $i < $ctrLASTROW + 1; $i++) {
…
user2694808
- 13
- 2
0
votes
1 answer
Perl ARGV value in scalar context
Given the following Perl script:
# USAGE: ./flurp -x -vf file1 file2 file3 file4
# e.
$a = shift;
$b = shift;
$c = shift;
@d = <>;
# ei. value of $b = -vf
# eii. value of @d = content of file2, file3, file4
print "$b\n";
print "@d\n";
print…
Alan W
- 291
- 1
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- 18
0
votes
1 answer
After successfully using grep on a variable it prints blank
I am opening a directory that has files that look like the following. Here is one file:
>UVWXY
ABCDEFGHIJKLMNOPQRSTUVWXYZ
>STUVW
ABCDEFGHIJKLMNOPQRSTUVWXYZ
>QRSTU
ABCDEFGHIJKLMNOPQRSTUVWXYZ
Here is a second file:
…
Rob
- 175
- 12
0
votes
2 answers
Need help getting perl array out of scalar context
I have a perl array I need to store in the following way:
$self->{spec}->{allImages} = @allImages;
Then I need to retrieve the contents later:
print Dumper($self->{spec}->{allImages});
This yields:
$VAR1 = 10;
(the number of items in the…
iLikeDirt
- 606
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