perl if line matches regex, ignore line and move onto next line in file - perl

Question

How would you do the following in perl:
for $line (#lines) {
if ($line =~ m/ImportantLineNotToBeChanged/){
#break out of the for loop, move onto the next line of the file being processed
#start the loop again
}
if ($line =~ s/SUMMER/WINTER/g){
print ".";
}
}
Updated to show more code, this is what I'm trying to do:
sub ChangeSeason(){
if (-f and /.log?/) {
$file = $_;
open FILE, $file;
#lines = <FILE>;
close FILE;
for $line (#lines) {
if ($line =~ m/'?Don't touch this line'?/) {
last;
}
if ($line =~ m/'?Or this line'?/){
last;
}
if ($line =~ m/'?Or this line too'?/){
last;
}
if ($line +~ m/'?Or this line as well'?/){
last;
}
if ($line =~ s/(WINTER)/{$1 eq 'winter' ? 'summer' : 'SUMMER'}/gie){
print ".";
}
}
print "\nSeason changed in file $_";
open FILE, ">$file";
print FILE #lines;
close FILE;
}
}

Answer 1

Just use next
for my $line (#lines) {
next if ($line =~ m/ImportantLineNotToBeChanged/);
if ($line =~ s/SUMMER/WINTER/g){
print ".";
}
}

Answer 2

for $line (#lines) {
unless ($line =~ m/ImportantLineNotToBeChanged/) {
if ($line =~ s/SUMMER/WINTER/g){
print ".";
}
}
}
A more concise method is
map { print "." if s/SUMMER/WINTER/g }
grep {!/ImportantLineNotToBeChanged/} #lines;
(I think I got that right.)

Answer 3

Just use the next feature.
for $line (#lines) {
if ($line =~ m/ImportantLineNotToBeChanged/){
#break out of the for loop, move onto the next line of the file being processed
#start the loop again
next;
}
if ($line =~ s/SUMMER/WINTER/g){
print ".";
}
}
Similarly, you can use "last" to finish the loop. For example:
for $line (#lines) {
if ($line =~ m/ImportantLineNotToBeChanged/){
#continue onto the next iteration of the for loop.
#skip everything in the rest of this iteration.
next;
}
if ($line =~ m/NothingImportantAFTERThisLine/){
#break out of the for loop completely.
#continue to code after loop
last;
}
if ($line =~ s/SUMMER/WINTER/g){
print ".";
}
}
#code after loop
Edit: 7pm on 6/13
I took your code and looked at it, rewrote some things and this is what I got:
sub changeSeason2 {
my $file= $_[0];
open (FILE,"<$file");
#lines = <FILE>;
close FILE;
foreach $line (#lines) {
if ($line =~ m/'?Don't touch this line'?/) {
next;
}
if ($line =~ m/'?Or this line'?/){
next;
}
if ($line =~ m/'?Or this line too'?/){
next;
}
if ($line =~ m/\'Or this line as well\'/){
next;
}
if ($line =~ s/(WINTER)/{$1 eq 'winter' ? 'summer' : 'SUMMER'}/gie){
print ".";
}
}
print "\nSeason changed in file $file";
open FILE, ">$file";
print FILE #lines;
close FILE;
}
Hope this helps some.

Answer 4

Unless I'm misunderstanding you, your "break out of the for loop, move onto the next line... [and] start the loop again" is just a complex way of saying "skip the loop body for this iteration".
for $line (#lines) {
unless (($line =~ m/ImportantLineNotToBeChanged/) {
if ($line =~ s/SUMMER/WINTER/g) {
print ".";
}
}
}