How to make tree of dictionaries?

[Vlad Sirenko]

I need:
dict = {2002 : {'Jan': {1 : 'num1', 2: 'num2', 3 : 'num3'},
{'Feb': {1 : 'num4', 2: 'num5', 3 : 'num6'} } }
2003 : {'Jan': {1 : 'num7', 2: 'num8', 3 : 'num9'} } }

How to do it programmatically?
In Perl I would do something like:

while ($line = <>) {
if ($line =~ /^---\s+\w+\s+(\w+)\s+(\d*)\s+(\d+)\d+)\d+)\s+(\d+)\s+---$/) {
($month,$date,$hour,$minute,$sec,$year) = ($1,$2,$3,$4,$5,$6);
$statistics->{$year}->{$month}->{$date} += $sec;
}
}

But how to do it in Python without catching 'KeyError' exception or
iterating over some nested loops. How to do it elegantly?

 

[Aahz]

I need:
dict = {2002 : {'Jan': {1 : 'num1', 2: 'num2', 3 : 'num3'},
{'Feb': {1 : 'num4', 2: 'num5', 3 : 'num6'} } }
2003 : {'Jan': {1 : 'num7', 2: 'num8', 3 : 'num9'} } }

How to do it programmatically?
In Perl I would do something like:

while ($line = <>) {
if ($line =~ /^---\s+\w+\s+(\w+)\s+(\d*)\s+(\d+)\d+)\d+)\s+(\d+)\s+---$/) {
($month,$date,$hour,$minute,$sec,$year) = ($1,$2,$3,$4,$5,$6);
$statistics->{$year}->{$month}->{$date} += $sec;
}
}

But how to do it in Python without catching 'KeyError' exception or
iterating over some nested loops. How to do it elegantly?

You don't need nested loops, but you do need multiple statements:

tmp_year = stats.setdefault(year, {})
tmp_month = tmp_year.setdefault(month, {})
tmp_month[date] = tmp_month.setdefault(date, 0) + sec

 

[Michael Peuser]

This is what I love Perl for!
BTW: Do you really mean += ?
This does nor match yourt example, neither seems to make much sense. Perhaps
a misconception?

But how to do it in Python without catching 'KeyError' exception or
iterating over some nested loops. How to do it elegantly?

You don't need nested loops, but you do need multiple statements:

tmp_year = stats.setdefault(year, {})
tmp_month = tmp_year.setdefault(month, {})
tmp_month[date] = tmp_month.setdefault(date, 0) + sec

*I* think this is less readable than the Python expression!
Note that *get* and *setdefault* are most powerful operations on mapping
types
once you get used to them, that is...

Kindly
Michael P