[Numpy-discussion] column_stack with mixed data types
Ryan Krauss
ryanlists at gmail.com
Mon Jul 30 18:22:24 EDT 2007
In writing a function to parse my data, I ran into some unexpected
behavior. Is it intentional that a recarray can only be created by a
list of tuples and not by a list of lists?
Here is what I ran into:
ipdb>biglist[0:10]
Out[68]:
[[7, 20.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875, 2.75, ''],
[8, 20.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875, 2.75, ''],
[9, 20.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875, 2.75, ''],
[10, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875, ''],
[11, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875, ''],
[12, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875, ''],
[13, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875, 'With headliner'],
[14, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875, 'With headliner'],
[15, 20.0, 'HE 4.0 pcf', 'Hemi', '0.2493', 32.6875, 5.25, ''],
[16, 20.0, 'HE 4.0 pcf', 'Hemi', '0.2493', 32.6875, 5.25, '']]
ipdb>tuplelist=[tuple(row) for row in biglist]
ipdb>tuplelist[0:10]
Out[68]:
[(7, 20.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875, 2.75, ''),
(8, 20.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875, 2.75, ''),
(9, 20.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875, 2.75, ''),
(10, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875, ''),
(11, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875, ''),
(12, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875, ''),
(13, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875, 'With headliner'),
(14, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875, 'With headliner'),
(15, 20.0, 'HE 4.0 pcf', 'Hemi', '0.2493', 32.6875, 5.25, ''),
(16, 20.0, 'HE 4.0 pcf', 'Hemi', '0.2493', 32.6875, 5.25, '')]
ipdb>dt
Out[68]: dtype([('Test Number', '<i4'), ('Foam Thick. (mm)', '<f8'),
('Foam Description', '|S14'), ('Impactor', '|S14'), ('Mass (kg)',
'|S14'), ('Drop Height (in.)', '<f8'), ('Flag Height (in.)', '<f8'),
('Notes', '|S14')])
ipdb>array(biglist, dtype=dt)
*** TypeError: expected a readable buffer object
This does not work for a list of lists, but does work for a list of tuples:
ipdb>array(tuplelist, dtype=dt)
Out[68]:
array([(7, 20.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875, 2.75, ''),
(8, 20.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875, 2.75, ''),
(9, 20.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875, 2.75, ''),
(10, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875, ''),
(11, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875, ''),
(12, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875, ''),
(13, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875,
'With headliner'),
(14, 20.0, 'HE 4.0 pcf', 'Flat', 'Large', 32.6875, 4.6875,
'With headliner'),
(15, 20.0, 'HE 4.0 pcf', 'Hemi', '0.2493', 32.6875, 5.25, ''),
(16, 20.0, 'HE 4.0 pcf', 'Hemi', '0.2493', 32.6875, 5.25, ''),
(17, 20.0, 'HE 4.0 pcf', 'Hemi', '0.2493', 32.6875, 5.25, ''),
(18, 15.0, 'HE 4.0 pcf', 'Hemi', '0.2493', 32.6875, 5.0, ''),
(19, 15.0, 'HE 4.0 pcf', 'Hemi', '0.2493', 32.6875, 5.0, ''),
(20, 15.0, 'HE 4.0 pcf', 'Hemi', '0.2493', 32.6875, 5.0, ''),
(21, 15.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875, 2.5625, ''),
(22, 15.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875, 2.5625, ''),
(23, 15.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875, 2.5625, ''),
(24, 10.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875,
2.2812999999999999, ''),
(25, 10.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875,
2.2812999999999999, ''),
(26, 10.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875,
2.2812999999999999, ''),
(27, 5.0, 'HE 4.0 pcf', 'Flat', 'Small', 32.6875,
2.0937999999999999, ''),
(28, 20.0, 'P420', 'Flat', 'Small', 32.6875, 2.7812999999999999, ''),
(29, 20.0, 'P420', 'Flat', 'Small', 32.6875, 2.7812999999999999, ''),
(30, 20.0, 'E175', 'Flat', 'Small', 32.6875, 2.7812999999999999, ''),
(31, 20.0, 'E175', 'Flat', 'Small', 32.6875, 2.7812999999999999, ''),
(32, 20.0, 'E175', 'Flat', 'Small', 32.6875, 2.7812999999999999, ''),
(33, 20.0, 'E175', 'Flat', 'Small', 32.6875, 2.7812999999999999, ''),
(34, 15.0, 'E175', 'Flat', 'Small', 32.6875, 2.5, ''),
(35, 15.0, 'E175', 'Flat', 'Small', 32.6875, 2.5, ''),
(36, 15.0, 'E175', 'Flat', 'Small', 32.6875, 2.5, ''),
(37, 20.0, 'E175', 'Hemi', '0.2493', 32.6875, 5.1875, ''),
(38, 20.0, 'E175', 'Hemi', '0.2493', 32.6875, 5.1875, ''),
(39, 20.0, 'E175', 'Hemi', '0.2493', 32.6875, 5.1875, ''),
(40, 15.0, 'E175', 'Hemi', '0.2493', 32.6875, 5.0, ''),
(41, 15.0, 'E175', 'Hemi', '0.2493', 32.6875, 5.0, ''),
(42, 15.0, 'E175', 'Hemi', '0.2493', 32.6875, 5.0, ''),
(43, 15.0, 'E175', 'Flat', 'Small', 10.5625, 2.5625, ''),
(44, 15.0, 'E175', 'Flat', 'Small', 10.5625, 2.5625, ''),
(45, 15.0, 'E175', 'Flat', 'Small', 10.5625, 2.5625, ''),
(46, 15.0, 'HE 4.0 pcf', 'Flat', 'Small', 10.5625, 2.5625, ''),
(47, 15.0, 'HE 4.0 pcf', 'Flat', 'Small', 10.5625, 2.5625, ''),
(48, 15.0, 'HE 4.0 pcf', 'Flat', 'Small', 10.5625, 2.5625, ''),
(49, 10.0, 'HE 4.0 pcf', 'Flat', 'Small', 10.25, 2.25, ''),
(50, 10.0, 'HE 4.0 pcf', 'Flat', 'Small', 10.25, 2.25, ''),
(51, 10.0, 'HE 4.0 pcf', 'Flat', 'Small', 10.25, 2.25, ''),
(52, 10.0, 'E175', 'Flat', 'Small', 10.25, 2.25, ''),
(53, 10.0, 'E175', 'Flat', 'Small', 10.25, 2.25, ''),
(54, 10.0, 'E175', 'Flat', 'Small', 10.25, 2.25, ''),
(55, 5.0, 'HE 4.0 pcf', 'Flat', 'Small', 10.125, 2.1875, ''),
(56, 5.0, 'HE 4.0 pcf', 'Flat', 'Small', 10.125, 2.1875, ''),
(57, 5.0, 'HE 4.0 pcf', 'Flat', 'Small', 10.125, 2.1875, ''),
(58, 15.0, 'HE 4.0 pcf', 'Flat', 'Large', 12.5, 4.5, ''),
(59, 15.0, 'HE 4.0 pcf', 'Flat', 'Large', 12.5, 4.5, ''),
(60, 15.0, 'HE 4.0 pcf', 'Flat', 'Large', 12.5, 4.5, ''),
(61, 15.0, 'E175', 'Flat', 'Large', 12.5, 4.5, ''),
(62, 15.0, 'E175', 'Flat', 'Large', 12.5, 4.5, ''),
(63, 15.0, 'E175', 'Flat', 'Large', 12.5, 4.5, ''),
(64, 10.0, 'HE 4.0 pcf', 'Flat', 'Large', 12.125, 4.375, ''),
(65, 10.0, 'HE 4.0 pcf', 'Flat', 'Large', 12.125, 4.375, ''),
(66, 10.0, 'HE 4.0 pcf', 'Flat', 'Large', 12.125, 4.375, ''),
(67, 10.0, 'E175', 'Flat', 'Large', 12.125, 4.375, ''),
(68, 10.0, 'E175', 'Flat', 'Large', 12.125, 4.375, ''),
(69, 10.0, 'E175', 'Flat', 'Large', 12.125, 4.375, ''),
(70, 10.0, 'E175', 'Hemi', '0.2493', 12.875, 4.8125, ''),
(71, 10.0, 'E175', 'Hemi', '0.2493', 12.875, 4.8125, ''),
(72, 10.0, 'E175', 'Hemi', '0.2493', 12.875, 4.8125, ''),
(73, 10.0, 'HE 4.0 pcf', 'Hemi', '0.2493', 12.875, 4.8125, ''),
(74, 10.0, 'HE 4.0 pcf', 'Hemi', '0.2493', 12.875, 4.8125, ''),
(75, 10.0, 'HE 4.0 pcf', 'Hemi', '0.2493', 12.875, 4.8125, ''),
(76, 15.0, 'HE 4.0 pcf', 'Flat', 'Small', 18.3125, 2.5, ''),
(77, 15.0, 'HE 4.0 pcf', 'Flat', 'Small', 18.3125, 2.5, ''),
(78, 15.0, 'HE 4.0 pcf', 'Flat', 'Small', 18.3125, 2.5, ''),
(79, 15.0, 'E175', 'Flat', 'Small', 18.3125, 2.5, ''),
(80, 15.0, 'E175', 'Flat', 'Small', 18.3125, 2.5, ''),
(81, 15.0, 'E175', 'Flat', 'Small', 18.3125, 2.5, ''),
(82, 20.0, 'E175', 'Flat', 'Small', 45.6875, 2.7187999999999999, ''),
(83, 20.0, 'E175', 'Flat', 'Small', 45.6875, 2.7187999999999999, ''),
(84, 20.0, 'E175', 'Flat', 'Small', 45.6875, 2.7187999999999999, ''),
(85, 20.0, 'HE 4.0 pcf', 'Flat', 'Small', 45.6875,
2.7187999999999999, ''),
(86, 20.0, 'HE 4.0 pcf', 'Flat', 'Small', 45.6875,
2.7187999999999999, ''),
(87, 20.0, 'HE 4.0 pcf', 'Flat', 'Small', 45.6875,
2.7187999999999999, '')],
dtype=[('Test Number', '<i4'), ('Foam Thick. (mm)', '<f8'),
('Foam Description', '|S14'), ('Impactor', '|S14'), ('Mass (kg)',
'|S14'), ('Drop Height (in.)', '<f8'), ('Flag Height (in.)', '<f8'),
('Notes', '|S14')])
ipdb>
On 7/30/07, Ryan Krauss <ryanlists at gmail.com> wrote:
> I have data in a spreadsheet where the first column is an integer. the
> second is a float, columns 3-5 are strings, and columns 6 and 7 are
> floats. I have each column as a list, but when I use column_stack, I
> get back a 2D array of strings. What is the easiest way to get a
> recarray out of this list of lists? Is recarray my best/only choice?
>
> Thanks,
>
> Ryan
>
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