Python 在pyviz-hvplot生成的小部件中指定默认值
我有一个4D数据集,Python 在pyviz-hvplot生成的小部件中指定默认值,python,holoviews,pyviz,Python,Holoviews,Pyviz,我有一个4D数据集,hvplot很好地为我在groupby中指定的维度生成小部件: import xarray as xr ds = xr.open_dataset('http://gamone.whoi.edu/thredds/dodsC/coawst_4/use/fmrc/coawst_4_use_best.ncd') rho_vars = ['salt','temp'] from cartopy import crs as ccrs import hvplot.xarray impo
hvplot
很好地为我在groupby
中指定的维度生成小部件:
import xarray as xr
ds = xr.open_dataset('http://gamone.whoi.edu/thredds/dodsC/coawst_4/use/fmrc/coawst_4_use_best.ncd')
rho_vars = ['salt','temp']
from cartopy import crs as ccrs
import hvplot.xarray
import holoviews as hv
from geoviews import tile_sources as gvts
import panel as pn
var_select = pn.widgets.Select(name='Variables:', options=rho_vars,
value='temp')
crs = ccrs.PlateCarree()
def plot(var=None):
base_map = gvts.OSM
var = var or var_select.value
mesh = ds[var][-24:,:,:].hvplot.quadmesh(x='lon_rho', y='lat_rho', rasterize=True, title=var,
width=600, height=400, crs=crs,
groupby=list(ds[var].dims[:-2]), cmap='jet')
overlay = (base_map * mesh.opts(alpha=0.7)).opts(active_tools=['wheel_zoom', 'pan'])
widgets = {dim: pn.widgets.Select for dim in ds[var].dims[:-2]}
return pn.holoviews.HoloViews(overlay, widgets=widgets).layout
def on_var_select(event):
var = event.obj.value
dashboard[-1] = plot(var=var)
var_select.param.watch(on_var_select, parameter_names=['value']);
dashboard = pn.Column(var_select, plot(var_select.value))
产生:
但是,虽然hvplot
默认为选项的第一个值
orderedict
,但我希望默认为最后一个值
如果我查看仪表板元素:
print(dashboard)
Column
[0] Select(name='Variables:', options=OrderedDict([('salt', ...]), value='temp')
[1] Row
[0] HoloViews(DynamicMap, widgets={'time': <class 'panel.wid...})
[1] Column
[0] Select(name='Forecast time f..., options=OrderedDict([('2019-03-09 ...]), value=numpy.datetime64('2019-03-...)
[1] Select(name='S-coordinate a..., options=OrderedDict([('-0.96875', ...]), value=-0.96875)
这确实有效:
但是,我想制作一个独立的仪表板,当用户选择一个新变量时,它默认为最后一个值。对于当前代码,当选择新变量时,默认值不幸再次设置为第一个值
有没有办法将事后代码嵌入到绘图函数中来选择最后一个值,或者有没有其他更好的方法来实现这一点
.当您打印(仪表板)时可以看到,您有一个小部件的默认值
Column
[0] Select(name='Variables:', options=OrderedDict([('salt', ...]), value='temp')
[1] Row
[0] HoloViews(DynamicMap, widgets={'time': <class 'panel.wid...})
[1] Column
[0] Select(name='Forecast time f..., options=OrderedDict([('2019-03-09 ...]), value=numpy.datetime64('2019-03-...)
[1] Select(name='S-coordinate a..., options=OrderedDict([('-0.96875', ...]), value=-0.96875)
如果我正确理解了您的问题,使用hvplot可以做到这一点。Thomas,这似乎是正确的轨迹,但当我指定
Select(value=
所有其他参数,如Select)时(名称=,选项=< /代码>丢失。这是令人沮丧的。值得在面板中打开这个问题,我们应该考虑找到一个好的方法来指定这个。我不确定修改用户构造的小部件是否是最好的方法,即使在这种情况下也是方便的。
Column
[0] Select(name='Variables:', options=OrderedDict([('salt', ...]), value='temp')
[1] Row
[0] HoloViews(DynamicMap, widgets={'time': <class 'panel.wid...})
[1] Column
[0] Select(name='Forecast time f..., options=OrderedDict([('2019-03-09 ...]), value=numpy.datetime64('2019-03-...)
[1] Select(name='S-coordinate a..., options=OrderedDict([('-0.96875', ...]), value=-0.96875)
default_value = [...,...]
widgets = {dim: pn.widgets.Select(value=default_val[dim]) for dim in ds[var].dims[:-2]}