On 2019-12-10 03:12, ToddAndMargo via perl6-users wrote:
Today's revised revision of yesterday's new revisions
with amendments!
:-)
At it again;
perl 6: method:
12/10/2019 #2
Also see: "starts-with" and "ends-with"
References:
https://docs.raku.org/routine/contains
https://docs.raku.org/routine/starts-with
https://docs.raku.org/routine/ends-with
https://docs.raku.org/routine/lines
https://docs.raku.org/routine/fc
https://docs.raku.org/routine/so
https://docs.raku.org/syntax/Q
A method is a routine that you feed: Str.foo.
Think of "contains" as looking for a Needle in a Haystack.
You feed contains data and what you are lookig for. In
return is tells you True or False
say "abc".contains( "a" );
True
say "abc".contains( "z" );
False
my $x="\na\nb\nc\n"; for $x.lines -> $i {print "<$i>\n"};
<>
<a>
<b>
<c>
Case insensitive contains:
Note: "fc" converts you to lower case. It also converts weird
charters to
something on your keyboard
say "XYßZ".fc;
xyssz
if "2018 Jul 7".fc.contains( "jul".fc ) {say "Yes";}
Yes
if "2018 xJul 7".fc.contains( "jul".fc ) {say "Yes";}
Yes
if "2018 xul 7".fc.contains( "jul".fc ) {say "Yes";}
<nothing>
Excluding something from the search:
Warning: in the following, use "none" not "not" to negate if
"coming soon"
is found. "not" will always return False.
say so Q[<strong>2018.2.0; Coming
Soon</strong>].fc.contains("strong" & none "coming soon");
False
multi method contains(Str:D: Cool:D $needle, Int(Cool:D) $pos --> Bool)
"multi method"
This means there are multiple ways to address this, as in
multi method contains(Str:D: Cool:D $needle --> Bool)
multi method contains(Str:D: Str:D $needle --> Bool)
multi method contains(Str:D: Cool:D $needle, Int(Cool:D) $pos
--> Bool)
multi method contains(Str:D: Str:D $needle, Int:D $pos --> Bool)
"Str"
is the string data (Haystack) that will be operated on by the
method (contains)
":D"
means it wants actual data in the string and not a Nil.
The jargon for this requirement is that is is constrained
to an actual value
If it wanted a Nil, it would say ":U" or constrained to
a Nil
":"
is the delimiter that tells you it is finished defining
what is wants to be fed
"Cool:D $needle"
means it wants a type Cool (string or number) for the
substring ($needle) it is looking for in the Haystack (Str)
"Int(Cool:D)"
Means it will change a type Cool into a type Int (integer)
and the ":D" means it want some actual data and not a Nil.
"$pos"
Is short of Position. It is the starting index in the
haystack (Str) to start looking for the substring
(needle). Index starts at zero by way of string
convention in Perl 6
$pos is an optional parameter. Instead of $pos?
for optional, they stated it with several "multi method"
that do not include $pos.
"-->Bool"
means it return True or False
Notes: $pos in NOT pointing at Bool
--> means the return value
it is not a pointer
