平时做技术实践时，很多问题不是概念不会，而是细节没串起来。拿“perl读写文件代码实例”来说，它看着像小点，放到项目里常会牵出环境、配置、兼容性和维护成本。下面按实际采用顺序，把思路、关键写法和容易踩坑的地方讲清楚，便于大家直接对照操作。
#mode operand create truncate
#read <
#write > yes yes
#append >> yes
Case 1: Throw an exception if you cannot open the file:
复制代码 代码如下所示:
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 $row;
print "$rown";
}
close($fh);
Case 2: Give a warning if you cannot open the file, but keep running:
复制代码 代码如下所示:
use strict;
use warnings;
my $filename = 'data.txt';
if (open(my $fh, '<:encoding(UTF-8)', $filename)) {
while (my $row = <$fh>) {
chomp $row;
print "$rown";
}
close($fh);
} else {
warn "Could not open file '$filename' $!";
}
Case 3: Read one file into array
复制代码 代码如下所示:
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 $l (@FileContents){
print "$ln";
}
close FILEIN;
end