Numeric string conversion

[avram]

Are there any standard Unix command-line programs for converting number-like strings into numbers, and vice-versa? For example, converting…

• 1,000,000.00
• 1000000
• 1e6
• 1 * 10^6

…easily into one-another?

Comments

[stormsweeper.livejournal.com]

I'm fairly certain you can use awk.

[perldiver.livejournal.com]

$ perl -le '$_ = shift; s/,//; $_ += 0; print;' 5e6
5000000
$

This won't handle 1 * 10^6, but that isn't a number, it's an expression. It will handle all of your other examples.

[avram]

Thanks, but that only goes one way. It won't turn "5000000" into "5,000,000".

I'm probably best off either learning to use awk, or cobbling together a library.

[perldiver.livejournal.com]

You're better off learning to use Perl. It can do everything awk can do and more, plus it's actually a marketable skill in and of itself.

You hadn't mentioned before that you wanted the numbers displayed with commas, but that's easy enough--there's a standard recipe for it in the Perl Cookbook:

$ perl conv.pl 5e6 500000 5.1992
5,000,000
500,000
5.1992

--- Contents of conv.pl:
#!/usr/bin/perl -l

while (defined ($_ = shift)) {
print commify( map {s/,//; $_ += 0; } $_ );
}

sub commify {
my $text = reverse $_[0];
$text =~ s/(\d\d\d)(?=\d)(?!\d*\.)/$1,/g;
return scalar reverse $text;
}