diff options
| -rw-r--r-- | challenge-135/james-smith/README.md | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/challenge-135/james-smith/README.md b/challenge-135/james-smith/README.md index c9d91e5434..262d090ea3 100644 --- a/challenge-135/james-smith/README.md +++ b/challenge-135/james-smith/README.md @@ -45,7 +45,7 @@ It is possible to compact this slightly - buy 1 - assuming `$n` is an integer, a ```perl sub middle3compact { my$l=length(my$n=abs$_[0]); - $l<3?'Too short':$l%2?substr$n,$l/2-1,3:'Even digits'; + $l<3?'Too short':$l%2?substr$n,$l/2-1,3:'Even digits' } ``` @@ -55,14 +55,14 @@ sub middle3compact { ## Solution -You find about SEDOL numbers on Wikipedia at https://en.wikipedia.org/wiki/SEDOL. +You find about SEDOL (Stock Exchange Daily Official List) numbers on Wikipedia at https://en.wikipedia.org/wiki/SEDOL. The consist of 6 digits/consonants + a checksum digit. The weighted sum of the 6 digits + the checksum is a multiple of 10. -The weights are 1, 3, 1, 7, 3 and 9 for the six digits and the checksum. +The weights are 1, 3, 1, 7, 3 and 9 for the six digits and 1 for the checksum. We have to: - * validate the number is a SEDOL number - * compute the weighted sum + * validate the number is of valid format for a SEDOL number - 6 numbers or consonants & a single number. + * compute the weighted sum (using ord to convert the B-Z characters to their numeric equivalends) * check to see if it is a multiple of 10 ```perl @@ -70,7 +70,7 @@ sub is_sedol { ## Check correct format... numbers and consonants only return 0 unless $_[0] =~ m{^[0-9B-HJ-NP-TW-Z]{6}\d$}; -## Accumulator and weights for each charachter +## Accumulator and weights for each character my( $t, @w ) = qw(0 1 3 1 7 3 9 1); ## Calculate SEDOL sum... note YODA sum -55 + ord $_ to avoid precedence issue @@ -80,16 +80,18 @@ sub is_sedol { return $t % 10 ? 0 : 1; } ``` + Again we can compact the code - by removing spaces and a couple of rewrites: * replace `unless $x=~//` with `if $x!~//`; * flip `@w` and use `pop`. + * Note `0if` expands as `0 if`. ```perl sub is_sedol_compact { return 0if$_[0]!~/^[0-9B-HJ-NP-TW-Z]{6}\d$/; my($t,@w)=qw(0 1 9 3 7 1 3 1); $t+=(/\d/?$_:-55+ord$_)*pop@w for split//,$_[0]; - $t%10?0:1; + $t%10?0:1 } ``` |