试图从 pdb 文件中取出所有 ATOM [英] Trying to take out all ATOM from pdb file

问题描述

您好，我正在尝试从 pdb 文件中取出所有以 ATOM 开头的行.出于某种原因，我遇到了麻烦.我的代码是:

Hello I am trying to take out all the lines that start with ATOM from a pdb file. For some reason, I am having trouble. My code is:

open (FILE, $ARGV[0])
    or die "Could not open file\n";

my @newlines;
my $atomcount = 0;
while ( my $lines = <FILE> ) {
    if ($lines =~ m/^ATOM.*/) {
    @newlines = $lines;
    $atomcount++;
}
}

print "@newlines\n";
print "$atomcount\n";

推荐答案

行

 @newlines = $lines;

将 $lines 重新分配给数组 @newlines，从而在 while 循环的每次迭代中覆盖它.您更愿意将每个 $lines append 附加到 @newlines，所以

re-assigns $lines to the array @newlines and thus overwrites it with every iteration of the while loop. You rather want to append every $lines to @newlines, so

push @newlines, $lines;

会起作用.

旁注:变量名 $lines 应该是 $line(只是为了便于阅读)因为它只是 一行，而不是 多行.

Sidenote: The variable name $lines should be $line (just for readability) because it's just one line, not multiple lines.

您可以只使用 @newlines 中的项目数，而不是显式计算附加到 @newlines 的项目(使用 $atomcount++;)> 循环后:

Instead of explicitly counting the items appended to @newlines (with $atomcount++;) you can just use the number of items in @newlines after the loop:

my @newlines;
while ( my $line = <FILE> ) {
    if ($line =~ m/^ATOM.*/) {
        push @newlines, $line;
    }
}

my $atomcount = @newlines; # in scalar context this is the number of items in @newlines
print "@newlines\n";
print "$atomcount\n";

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