issues

What is your issue?

Importing the xarray package takes a significant amount of time. For instance: ❯ time python -c "import xarray" python -c "import xarray" 1.44s user 0.52s system 132% cpu 1.476 total compared to others ``` ❯ time python -c "import pandas" python -c "import pandas" 0.45s user 0.35s system 177% cpu 0.447 total

❯ time python -c "import scipy" python -c "import scipy" 0.29s user 0.23s system 297% cpu 0.175 total

❯ time python -c "import numpy" python -c "import numpy" 0.29s user 0.43s system 313% cpu 0.229 total

❯ time python -c "import datetime" python -c "import datetime" 0.05s user 0.00s system 99% cpu 0.051 total ``` I am obviously not surprised that importing xarray takes longer than importing Pandas, Numpy or the datetime module, but 1.5 s is something you clearly notice when it is done e.g. by a command-line application.

I inquired about import performance and found out about a lazy module loader proposal by the Scientific Python community. AFAIK SciPy uses a similar system to populate its namespaces without import time penalty. Would it be possible for xarray to use delayed imports when relevant?

What happened: After updating xarray to v0.20.1, some of my multi-index-based selection code raises a TypeError.

What you expected to happen: Selection should work in the case I am considering.

Minimal Complete Verifiable Example:

```python import xarray as xr import pandas as pd

da = xr.DataArray(data=[0, 1, 2, 3], dims=("x",)).reindex( {"x": pd.MultiIndex.from_product((["foo", "bar"], [0, 1]), names=("str", "int"))} ) print(da.sel(x=("foo", 1))) ```

Expected output (what I get with xarray 0.19.0):

<xarray.DataArray ()> array(1) Coordinates: x object ('foo', 1)

Actual output (with xarray 0.20.1):

Traceback (most recent call last): File "playgrounds/xarray_mwe.py", line 7, in <module> da.sel(x=("foo", 1)) File "/Users/leroyv/miniforge3/envs/eradiate/lib/python3.7/site-packages/xarray/core/dataarray.py", line 1337, in sel **indexers_kwargs, File "/Users/leroyv/miniforge3/envs/eradiate/lib/python3.7/site-packages/xarray/core/dataset.py", line 2505, in sel self, indexers=indexers, method=method, tolerance=tolerance File "/Users/leroyv/miniforge3/envs/eradiate/lib/python3.7/site-packages/xarray/core/coordinates.py", line 422, in remap_label_indexers obj, v_indexers, method=method, tolerance=tolerance File "/Users/leroyv/miniforge3/envs/eradiate/lib/python3.7/site-packages/xarray/core/indexing.py", line 120, in remap_label_indexers idxr, new_idx = index.query(labels, method=method, tolerance=tolerance) File "/Users/leroyv/miniforge3/envs/eradiate/lib/python3.7/site-packages/xarray/core/indexes.py", line 235, in query label_value, method=method, tolerance=tolerance TypeError: get_loc() got an unexpected keyword argument 'tolerance'

Anything else we need to know?: Nothing I'm aware of

Environment: