[Numpy-discussion] Outer join ?
Thu Feb 12 10:19:05 CST 2009
On 2/11/09, Robert Kern <firstname.lastname@example.org> wrote:
> On Wed, Feb 11, 2009 at 23:24, A B <email@example.com> wrote:
>> I have the following data structure:
>> col1 | col2 | col3
>> For each key in the second column, I would like to create an array
>> where for all unique values in the first column, there will be either
>> a value or zero if there is no data available. Like so:
>> # 20080101, 20080201, 20080301, 20080601
>> key1 - 4, 6, 5, 0
>> key2 - 0, 0, 3.4, 5.6
>> Ideally, the results would end up in a 2d array.
>> What's the most efficient way to accomplish this? Currently, I am
>> getting a list of uniq col1 and col2 values into separate variables,
>> then looping through each unique value in col2
>> a = loadtxt(...)
>> dates = unique(a[:]['col1'])
>> keys = unique(a[:]['col2'])
>> for key in keys:
>> b = a[where(a[:]['col2'] == key)]
> Take a look at setmember1d().
> Robert Kern
Thanks. That's exactly what I need, but I'm not sure about the next
step after I do
and have the bool arr/mask ... How can I grow b to have 0 values for
the missing keys?
More information about the Numpy-discussion