CLN-29547 replace old string formatting

pandas/_libs/tslibs/c_timestamp.pyx

@@ -59,10 +59,10 @@ def integer_op_not_supported(obj):
 
     # GH#30886 using an fstring raises SystemError
     int_addsub_msg = (
-        "Addition/subtraction of integers and integer-arrays with {cls} is "
-        "no longer supported.  Instead of adding/subtracting `n`, "
-        "use `n * obj.freq`"
-    ).format(cls=cls)
+        f"Addition/subtraction of integers and integer-arrays with {cls} is "
+        f"no longer supported.  Instead of adding/subtracting `n`, "
+        f"use `n * obj.freq`"
+    )
     return TypeError(int_addsub_msg)
 
 

pandas/_libs/tslibs/timedeltas.pyx

@@ -639,7 +639,7 @@ cdef inline int64_t parse_iso_format_string(object ts) except? -1:
         bint have_dot = 0, have_value = 0, neg = 0
         list number = [], unit = []
 
-    err_msg = "Invalid ISO 8601 Duration format - {}".format(ts)
+    err_msg = f"Invalid ISO 8601 Duration format - {ts}"
 
     for c in ts:
         # number (ascii codes)

pandas/core/arrays/interval.py

@@ -1126,8 +1126,8 @@ def __arrow_array__(self, type=None):
             subtype = pyarrow.from_numpy_dtype(self.dtype.subtype)
         except TypeError:
             raise TypeError(
-                "Conversion to arrow with subtype '{}' "
-                "is not supported".format(self.dtype.subtype)
+                f"Conversion to arrow with subtype '{self.dtype.subtype}' "
+                f"is not supported"
             )
         interval_type = ArrowIntervalType(subtype, self.closed)
         storage_array = pyarrow.StructArray.from_arrays(
@@ -1155,15 +1155,13 @@ def __arrow_array__(self, type=None):
                 # ensure we have the same subtype and closed attributes
                 if not type.equals(interval_type):
                     raise TypeError(
-                        "Not supported to convert IntervalArray to type with "
-                        "different 'subtype' ({0} vs {1}) and 'closed' ({2} vs {3}) "
-                        "attributes".format(
-                            self.dtype.subtype, type.subtype, self.closed, type.closed
-                        )
+                        f"Not supported to convert IntervalArray to type with "
+                        f"different 'subtype' ({self.dtype.subtype} vs {type.subtype}) "
+                        f"and 'closed' ({self.closed} vs {type.closed}) attributes"
                     )
             else:
                 raise TypeError(
-                    "Not supported to convert IntervalArray to '{0}' type".format(type)
+                    f"Not supported to convert IntervalArray to '{type}' type"
                 )
 
         return pyarrow.ExtensionArray.from_storage(interval_type, storage_array)
@@ -1175,7 +1173,7 @@ def __arrow_array__(self, type=None):
 
         Parameters
         ----------
-        na_tuple : boolean, default True
+        na_tuple : bool, default True
             Returns NA as a tuple if True, ``(nan, nan)``, or just as the NA
             value itself if False, ``nan``.
 

pandas/core/util/hashing.py

@@ -295,7 +295,7 @@ def hash_array(
     elif issubclass(dtype.type, (np.datetime64, np.timedelta64)):
         vals = vals.view("i8").astype("u8", copy=False)
     elif issubclass(dtype.type, np.number) and dtype.itemsize <= 8:
-        vals = vals.view("u{}".format(vals.dtype.itemsize)).astype("u8")
+        vals = vals.view(f"u{vals.dtype.itemsize}").astype("u8")
     else:
         # With repeated values, its MUCH faster to categorize object dtypes,
         # then hash and rename categories. We allow skipping the categorization

pandas/io/formats/format.py

@@ -187,7 +187,7 @@ def _get_footer(self) -> str:
         if self.length:
             if footer:
                 footer += ", "
-            footer += "Length: {length}".format(length=len(self.categorical))
+            footer += f"Length: {len(self.categorical)}"
 
         level_info = self.categorical._repr_categories_info()
 
@@ -217,7 +217,7 @@ def to_string(self) -> str:
 
         fmt_values = self._get_formatted_values()
 
-        fmt_values = ["{i}".format(i=i) for i in fmt_values]
+        fmt_values = [f"{i}" for i in fmt_values]
         fmt_values = [i.strip() for i in fmt_values]
         values = ", ".join(fmt_values)
         result = ["[" + values + "]"]
@@ -301,28 +301,26 @@ def _get_footer(self) -> str:
             assert isinstance(
                 self.series.index, (ABCDatetimeIndex, ABCPeriodIndex, ABCTimedeltaIndex)
             )
-            footer += "Freq: {freq}".format(freq=self.series.index.freqstr)
+            footer += f"Freq: {self.series.index.freqstr}"
 
         if self.name is not False and name is not None:
             if footer:
                 footer += ", "
 
             series_name = pprint_thing(name, escape_chars=("\t", "\r", "\n"))
-            footer += (
-                ("Name: {sname}".format(sname=series_name)) if name is not None else ""
-            )
+            footer += f"Name: {series_name}" if name is not None else ""
 
         if self.length is True or (self.length == "truncate" and self.truncate_v):
             if footer:
                 footer += ", "
-            footer += "Length: {length}".format(length=len(self.series))
+            footer += f"Length: {len(self.series)}"
 
         if self.dtype is not False and self.dtype is not None:
             name = getattr(self.tr_series.dtype, "name", None)
             if name:
                 if footer:
                     footer += ", "
-                footer += "dtype: {typ}".format(typ=pprint_thing(name))
+                footer += f"dtype: {pprint_thing(name)}"
 
         # level infos are added to the end and in a new line, like it is done
         # for Categoricals
@@ -359,9 +357,7 @@ def to_string(self) -> str:
         footer = self._get_footer()
 
         if len(series) == 0:
-            return "{name}([], {footer})".format(
-                name=type(self.series).__name__, footer=footer
-            )
+            return f"{type(self.series).__name__}([], {footer})"
 
         fmt_index, have_header = self._get_formatted_index()
         fmt_values = self._get_formatted_values()
@@ -584,10 +580,8 @@ def __init__(
             self.formatters = formatters
         else:
             raise ValueError(
-                (
-                    "Formatters length({flen}) should match "
-                    "DataFrame number of columns({dlen})"
-                ).format(flen=len(formatters), dlen=len(frame.columns))
+                f"Formatters length({len(formatters)}) should match "
+                f"DataFrame number of columns({len(frame.columns)})"
             )
         self.na_rep = na_rep
         self.decimal = decimal
@@ -816,10 +810,10 @@ def write_result(self, buf: IO[str]) -> None:
         frame = self.frame
 
         if len(frame.columns) == 0 or len(frame.index) == 0:
-            info_line = "Empty {name}\nColumns: {col}\nIndex: {idx}".format(
-                name=type(self.frame).__name__,
-                col=pprint_thing(frame.columns),
-                idx=pprint_thing(frame.index),
+            info_line = (
+                f"Empty {type(self.frame).__name__}\n"
+                f"Columns: {pprint_thing(frame.columns)}\n"
+                f"Index: {pprint_thing(frame.index)}"
             )
             text = info_line
         else:
@@ -865,11 +859,7 @@ def write_result(self, buf: IO[str]) -> None:
         buf.writelines(text)
 
         if self.should_show_dimensions:
-            buf.write(
-                "\n\n[{nrows} rows x {ncols} columns]".format(
-                    nrows=len(frame), ncols=len(frame.columns)
-                )
-            )
+            buf.write(f"\n\n[{len(frame)} rows x {len(frame.columns)} columns]")
 
     def _join_multiline(self, *args) -> str:
         lwidth = self.line_width
@@ -1075,7 +1065,7 @@ def _get_formatted_index(self, frame: "DataFrame") -> List[str]:
 
         # empty space for columns
         if self.show_col_idx_names:
-            col_header = ["{x}".format(x=x) for x in self._get_column_name_list()]
+            col_header = [f"{x}" for x in self._get_column_name_list()]
         else:
             col_header = [""] * columns.nlevels
 
@@ -1211,10 +1201,8 @@ def _format_strings(self) -> List[str]:
         if self.float_format is None:
             float_format = get_option("display.float_format")
             if float_format is None:
-                fmt_str = "{{x: .{prec:d}g}}".format(
-                    prec=get_option("display.precision")
-                )
-                float_format = lambda x: fmt_str.format(x=x)
+                precision = get_option("display.precision")
+                float_format = lambda x: f"{x: .{precision:d}g}"
         else:
             float_format = self.float_format
 
@@ -1240,10 +1228,10 @@ def _format(x):
                     pass
                 return self.na_rep
             elif isinstance(x, PandasObject):
-                return "{x}".format(x=x)
+                return f"{x}"
             else:
                 # object dtype
-                return "{x}".format(x=formatter(x))
+                return f"{formatter(x)}"
 
         vals = self.values
         if isinstance(vals, Index):
@@ -1259,7 +1247,7 @@ def _format(x):
         fmt_values = []
         for i, v in enumerate(vals):
             if not is_float_type[i] and leading_space:
-                fmt_values.append(" {v}".format(v=_format(v)))
+                fmt_values.append(f" {_format(v)}")
             elif is_float_type[i]:
                 fmt_values.append(float_format(v))
             else:
@@ -1268,8 +1256,8 @@ def _format(x):
                     # to include a space if we get here.
                     tpl = "{v}"
                 else:
-                    tpl = " {v}"
-                fmt_values.append(tpl.format(v=_format(v)))
+                    tpl = f" {_format(v)}"
+                fmt_values.append(tpl)
 
         return fmt_values
 
@@ -1442,7 +1430,7 @@ def _format_strings(self) -> List[str]:
 
 class IntArrayFormatter(GenericArrayFormatter):
     def _format_strings(self) -> List[str]:
-        formatter = self.formatter or (lambda x: "{x: d}".format(x=x))
+        formatter = self.formatter or (lambda x: f"{x: d}")
         fmt_values = [formatter(x) for x in self.values]
         return fmt_values
 
@@ -1726,7 +1714,7 @@ def _formatter(x):
             x = Timedelta(x)
         result = x._repr_base(format=format)
         if box:
-            result = "'{res}'".format(res=result)
+            result = f"'{result}'"
         return result
 
     return _formatter
@@ -1889,16 +1877,16 @@ def __call__(self, num: Union[int, float]) -> str:
             prefix = self.ENG_PREFIXES[int_pow10]
         else:
             if int_pow10 < 0:
-                prefix = "E-{pow10:02d}".format(pow10=-int_pow10)
+                prefix = f"E-{-int_pow10:02d}"
             else:
-                prefix = "E+{pow10:02d}".format(pow10=int_pow10)
+                prefix = f"E+{int_pow10:02d}"
 
         mant = sign * dnum / (10 ** pow10)
 
         if self.accuracy is None:  # pragma: no cover
             format_str = "{mant: g}{prefix}"
         else:
-            format_str = "{{mant: .{acc:d}f}}{{prefix}}".format(acc=self.accuracy)
+            format_str = f"{{mant: .{self.accuracy:d}f}}{{prefix}}"
 
         formatted = format_str.format(mant=mant, prefix=prefix)
 

pandas/io/formats/html.py

@@ -56,7 +56,7 @@ def __init__(
         self.table_id = self.fmt.table_id
         self.render_links = self.fmt.render_links
         if isinstance(self.fmt.col_space, int):
-            self.fmt.col_space = "{colspace}px".format(colspace=self.fmt.col_space)
+            self.fmt.col_space = f"{self.fmt.col_space}px"
 
     @property
     def show_row_idx_names(self) -> bool:
@@ -124,7 +124,7 @@ def write_th(
         """
         if header and self.fmt.col_space is not None:
             tags = tags or ""
-            tags += 'style="min-width: {colspace};"'.format(colspace=self.fmt.col_space)
+            tags += f'style="min-width: {self.fmt.col_space};"'
 
         self._write_cell(s, kind="th", indent=indent, tags=tags)
 
@@ -135,9 +135,9 @@ def _write_cell(
         self, s: Any, kind: str = "td", indent: int = 0, tags: Optional[str] = None
     ) -> None:
         if tags is not None:
-            start_tag = "<{kind} {tags}>".format(kind=kind, tags=tags)
+            start_tag = f"<{kind} {tags}>"
         else:
-            start_tag = "<{kind}>".format(kind=kind)
+            start_tag = f"<{kind}>"
 
         if self.escape:
             # escape & first to prevent double escaping of &
@@ -149,16 +149,13 @@ def _write_cell(
 
         if self.render_links and is_url(rs):
             rs_unescaped = pprint_thing(s, escape_chars={}).strip()
-            start_tag += '<a href="{url}" target="_blank">'.format(url=rs_unescaped)
+            start_tag += f'<a href="{rs_unescaped}" target="_blank">'
             end_a = "</a>"
         else:
             end_a = ""
 
         self.write(
-            "{start}{rs}{end_a}</{kind}>".format(
-                start=start_tag, rs=rs, end_a=end_a, kind=kind
-            ),
-            indent,
+            f"{start_tag}{rs}{end_a}</{kind}>", indent,
         )
 
     def write_tr(
@@ -177,7 +174,7 @@ def write_tr(
         if align is None:
             self.write("<tr>", indent)
         else:
-            self.write('<tr style="text-align: {align};">'.format(align=align), indent)
+            self.write(f'<tr style="text-align: {align};">', indent)
         indent += indent_delta
 
         for i, s in enumerate(line):
@@ -196,9 +193,7 @@ def render(self) -> List[str]:
         if self.should_show_dimensions:
             by = chr(215)  # ×
             self.write(
-                "<p>{rows} rows {by} {cols} columns</p>".format(
-                    rows=len(self.frame), by=by, cols=len(self.frame.columns)
-                )
+                f"<p>{len(self.frame)} rows {by} {len(self.frame.columns)} columns</p>"
             )
 
         return self.elements
@@ -216,20 +211,18 @@ def _write_table(self, indent: int = 0) -> None:
                 self.classes = self.classes.split()
             if not isinstance(self.classes, (list, tuple)):
                 raise TypeError(
-                    "classes must be a string, list, "
+                    f"classes must be a string, list, "
                     f"or tuple, not {type(self.classes)}"
                 )
             _classes.extend(self.classes)
 
         if self.table_id is None:
             id_section = ""
         else:
-            id_section = ' id="{table_id}"'.format(table_id=self.table_id)
+            id_section = f' id="{self.table_id}"'
 
         self.write(
-            '<table border="{border}" class="{cls}"{id_section}>'.format(
-                border=self.border, cls=" ".join(_classes), id_section=id_section
-            ),
+            f'<table border="{self.border}" class="{" ".join(_classes)}"{id_section}>',
             indent,
         )