本文整理汇总了Python中astropy.table.QTable.group_by方法的典型用法代码示例。如果您正苦于以下问题：Python QTable.group_by方法的具体用法？Python QTable.group_by怎么用？Python QTable.group_by使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类astropy.table.QTable的用法示例。
在下文中一共展示了QTable.group_by方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Python代码示例。
示例1: test_group_mixins
# 需要导入模块: from astropy.table import QTable [as 别名]
# 或者: from astropy.table.QTable import group_by [as 别名]
def test_group_mixins():
"""
Test grouping a table with mixin columns
"""
# Setup mixins
idx = np.arange(4)
x = np.array([3., 1., 2., 1.])
q = x * u.m
lon = coordinates.Longitude(x * u.deg)
lat = coordinates.Latitude(x * u.deg)
# For Time do J2000.0 + few * 0.1 ns (this requires > 64 bit precision)
tm = time.Time(2000, format='jyear') + time.TimeDelta(x * 1e-10, format='sec')
sc = coordinates.SkyCoord(ra=lon, dec=lat)
aw = table_helpers.ArrayWrapper(x)
nd = np.array([(3, 'c'), (1, 'a'), (2, 'b'), (1, 'a')],
dtype='<i4,|S1').view(NdarrayMixin)
qt = QTable([idx, x, q, lon, lat, tm, sc, aw, nd],
names=['idx', 'x', 'q', 'lon', 'lat', 'tm', 'sc', 'aw', 'nd'])
# Test group_by with each supported mixin type
mixin_keys = ['x', 'q', 'lon', 'lat', 'tm', 'sc', 'aw', 'nd']
for key in mixin_keys:
qtg = qt.group_by(key)
# Test that it got the sort order correct
assert np.all(qtg['idx'] == [1, 3, 2, 0])
# Test that the groups are right
# Note: skip testing SkyCoord column because that doesn't have equality
for name in ['x', 'q', 'lon', 'lat', 'tm', 'aw', 'nd']:
assert np.all(qt[name][[1, 3]] == qtg.groups[0][name])
assert np.all(qt[name][[2]] == qtg.groups[1][name])
assert np.all(qt[name][[0]] == qtg.groups[2][name])
# Test that unique also works with mixins since most of the work is
# done with group_by(). This is using *every* mixin as key.
uqt = unique(qt, keys=mixin_keys)
assert len(uqt) == 3
assert np.all(uqt['idx'] == [1, 2, 0])
assert np.all(uqt['x'] == [1., 2., 3.])
# Column group_by() with mixins
idxg = qt['idx'].group_by(qt[mixin_keys])
assert np.all(idxg == [1, 3, 2, 0])