Perl read-write file code instance _perl

#mode operand Create truncate
#read <
#write > Yes
#append >> Yes

Case 1:throw A exception if you cannot open the file:

Copy Code code as follows:

Use strict;
Use warnings;

My $filename = ' data.txt ';
Open (My $fh, ' <:encoding (UTF-8) ', $filename)
Or die "Could not open file ' $filename ' with the error $!";

while (My $row = < $fh >) {
Chomp $row;
print "$row \ n";
}
Close ($FH);

　　

Case 2:give A warning if you cannot open the file, but keep running:

Copy Code code as follows:

Use strict;
Use warnings;

My $filename = ' data.txt ';
if (open (My $fh, ' <:encoding (UTF-8) ', $filename)) {
while (My $row = < $fh >) {
Chomp $row;
print "$row \ n";
}
Close ($FH);
} else {
Warn "Could not open file ' $filename ' $!";
}

　　

Case 3:read one file into array

Copy Code code as follows:

Use strict;
Use warnings;

My $filename = ' data.txt ';
Open (Filein, "<", $filename)
Or die "Could not open file ' $filename ' with the error $!";
My @FileContents = <FILEIN>;
For my $l (@FileContents) {
print "$l \ n";
}
Close Filein;

　　

End