Enforce ruff/flynt rules (FLY) (pydata#10375)

* Apply ruff/flynt rule FLY002

FLY002 Consider f-string instead of string join

* Enforce ruff/flynt rules (FLY)

Author: DimitriPapadopoulos

pyproject.toml

@@ -255,6 +255,7 @@ extend-select = [
   "PIE",  # flake8-pie
   "TID",  # flake8-tidy-imports (absolute imports)
   "PYI",  # flake8-pyi
+  "FLY",  # flynt
   "I",    # isort
   "PERF", # Perflint
   "W",    # pycodestyle warnings

xarray/convert.py

@@ -138,7 +138,7 @@ def _iris_cell_methods_to_str(cell_methods_obj):
             f"interval: {interval}" for interval in cell_method.intervals
         )
         comments = " ".join(f"comment: {comment}" for comment in cell_method.comments)
-        extra = " ".join([intervals, comments]).strip()
+        extra = f"{intervals} {comments}".strip()
         if extra:
             extra = f" ({extra})"
         cell_methods.append(names + cell_method.method + extra)

xarray/core/formatting.py

@@ -894,7 +894,7 @@ def extra_items_repr(extra_keys, mapping, ab_side, kwargs):
                     attrs_summary.append(attr_s)
 
                 temp = [
-                    "\n".join([var_s, attr_s]) if attr_s else var_s
+                    f"{var_s}\n{attr_s}" if attr_s else var_s
                     for var_s, attr_s in zip(temp, attrs_summary, strict=True)
                 ]
 

xarray/tests/test_cftime_offsets.py

@@ -274,7 +274,7 @@ def test_to_offset_annual(month_label, month_int, multiple, offset_str):
     freq = offset_str
     offset_type = _ANNUAL_OFFSET_TYPES[offset_str]
     if month_label:
-        freq = "-".join([freq, month_label])
+        freq = f"{freq}-{month_label}"
     if multiple:
         freq = f"{multiple}{freq}"
     result = to_offset(freq)
@@ -303,7 +303,7 @@ def test_to_offset_quarter(month_label, month_int, multiple, offset_str):
     freq = offset_str
     offset_type = _QUARTER_OFFSET_TYPES[offset_str]
     if month_label:
-        freq = "-".join([freq, month_label])
+        freq = f"{freq}-{month_label}"
     if multiple:
         freq = f"{multiple}{freq}"
     result = to_offset(freq)