CLN: replace str.format() in pandas/io/formats

pandas/io/formats/css.py

@@ -17,10 +17,7 @@ def expand(self, prop, value):
         try:
             mapping = self.SIDE_SHORTHANDS[len(tokens)]
         except KeyError:
-            warnings.warn(
-                'Could not expand "{prop}: {val}"'.format(prop=prop, val=value),
-                CSSWarning,
-            )
+            warnings.warn(f"Could not expand '{prop}: {value}'", CSSWarning)
             return
         for key, idx in zip(self.SIDES, mapping):
             yield prop_fmt.format(key), tokens[idx]
@@ -110,14 +107,14 @@ def __call__(self, declarations_str, inherited=None):
 
         # 3. TODO: resolve other font-relative units
         for side in self.SIDES:
-            prop = "border-{side}-width".format(side=side)
+            prop = f"border-{side}-width"
             if prop in props:
                 props[prop] = self.size_to_pt(
                     props[prop], em_pt=font_size, conversions=self.BORDER_WIDTH_RATIOS
                 )
             for prop in [
-                "margin-{side}".format(side=side),
-                "padding-{side}".format(side=side),
+                f"margin-{side}",
+                f"padding-{side}",
             ]:
                 if prop in props:
                     # TODO: support %
@@ -206,9 +203,9 @@ def _error():
 
         val = round(val, 5)
         if int(val) == val:
-            size_fmt = "{fmt:d}pt".format(fmt=int(val))
+            size_fmt = f"{int(val):d}pt"
         else:
-            size_fmt = "{fmt:f}pt".format(fmt=val)
+            size_fmt = f"{val:f}pt"
         return size_fmt
 
     def atomize(self, declarations):

pandas/io/formats/excel.py

@@ -132,12 +132,10 @@ def build_border(self, props):
         return {
             side: {
                 "style": self._border_style(
-                    props.get("border-{side}-style".format(side=side)),
-                    props.get("border-{side}-width".format(side=side)),
-                ),
-                "color": self.color_to_excel(
-                    props.get("border-{side}-color".format(side=side))
+                    props.get(f"border-{side}-style"),
+                    props.get(f"border-{side}-width"),
                 ),
+                "color": self.color_to_excel(props.get(f"border-{side}-color")),
             }
             for side in ["top", "right", "bottom", "left"]
         }
@@ -427,7 +425,7 @@ def _format_value(self, val):
             if missing.isposinf_scalar(val):
                 val = self.inf_rep
             elif missing.isneginf_scalar(val):
-                val = "-{inf}".format(inf=self.inf_rep)
+                val = f"-{self.inf_rep}"
             elif self.float_format is not None:
                 val = float(self.float_format % val)
         if getattr(val, "tzinfo", None) is not None:
@@ -509,8 +507,8 @@ def _format_header_regular(self):
             if has_aliases:
                 if len(self.header) != len(self.columns):
                     raise ValueError(
-                        "Writing {cols} cols but got {alias} "
-                        "aliases".format(cols=len(self.columns), alias=len(self.header))
+                        f"Writing {len(self.columns)} cols but got {len(self.header)} "
+                        "aliases"
                     )
                 else:
                     colnames = self.header
@@ -718,8 +716,8 @@ def write(
         if num_rows > self.max_rows or num_cols > self.max_cols:
             raise ValueError(
                 "This sheet is too large! Your sheet size is: "
-                + "{}, {} ".format(num_rows, num_cols)
-                + "Max sheet size is: {}, {}".format(self.max_rows, self.max_cols)
+                + f"{num_rows}, {num_cols} "
+                + f"Max sheet size is: {self.max_rows}, {self.max_cols}"
             )
 
         if isinstance(writer, ExcelWriter):

pandas/io/formats/style.py

@@ -28,7 +28,6 @@
 
 jinja2 = import_optional_dependency("jinja2", extra="DataFrame.style requires jinja2.")
 
-
 try:
     import matplotlib.pyplot as plt
     from matplotlib import colors
@@ -165,7 +164,7 @@ def default_display_func(x):
             if self.na_rep is not None and pd.isna(x):
                 return self.na_rep
             elif is_float(x):
-                display_format = "{0:.{precision}f}".format(x, precision=self.precision)
+                display_format = f"{x:.{self.precision}f}"
                 return display_format
             else:
                 return x
@@ -293,7 +292,7 @@ def format_attr(pair):
             name = self.data.columns.names[r]
             cs = [
                 BLANK_CLASS if name is None else INDEX_NAME_CLASS,
-                "level{lvl}".format(lvl=r),
+                f"level{r}",
             ]
             name = BLANK_VALUE if name is None else name
             row_es.append(
@@ -310,8 +309,8 @@ def format_attr(pair):
                 for c, value in enumerate(clabels[r]):
                     cs = [
                         COL_HEADING_CLASS,
-                        "level{lvl}".format(lvl=r),
-                        "col{col}".format(col=c),
+                        f"level{r}",
+                        f"col{c}",
                     ]
                     cs.extend(
                         cell_context.get("col_headings", {}).get(r, {}).get(c, [])
@@ -339,7 +338,7 @@ def format_attr(pair):
             index_header_row = []
 
             for c, name in enumerate(self.data.index.names):
-                cs = [INDEX_NAME_CLASS, "level{lvl}".format(lvl=c)]
+                cs = [INDEX_NAME_CLASS, f"level{c}"]
                 name = "" if name is None else name
                 index_header_row.append(
                     {"type": "th", "value": name, "class": " ".join(cs)}
@@ -358,8 +357,8 @@ def format_attr(pair):
             for c, value in enumerate(rlabels[r]):
                 rid = [
                     ROW_HEADING_CLASS,
-                    "level{lvl}".format(lvl=c),
-                    "row{row}".format(row=r),
+                    f"level{c}",
+                    f"row{r}",
                 ]
                 es = {
                     "type": "th",
@@ -377,7 +376,7 @@ def format_attr(pair):
                 row_es.append(es)
 
             for c, col in enumerate(self.data.columns):
-                cs = [DATA_CLASS, "row{row}".format(row=r), "col{col}".format(col=c)]
+                cs = [DATA_CLASS, f"row{r}", f"col{c}"]
                 cs.extend(cell_context.get("data", {}).get(r, {}).get(c, []))
                 formatter = self._display_funcs[(r, c)]
                 value = self.data.iloc[r, c]
@@ -399,12 +398,7 @@ def format_attr(pair):
                         props.append(x.split(":"))
                     else:
                         props.append(["", ""])
-                cellstyle.append(
-                    {
-                        "props": props,
-                        "selector": "row{row}_col{col}".format(row=r, col=c),
-                    }
-                )
+                cellstyle.append({"props": props, "selector": f"row{r}_col{c}"})
             body.append(row_es)
 
         table_attr = self.table_attributes
@@ -971,9 +965,7 @@ def hide_columns(self, subset):
 
     @staticmethod
     def _highlight_null(v, null_color):
-        return (
-            "background-color: {color}".format(color=null_color) if pd.isna(v) else ""
-        )
+        return f"background-color: {null_color}" if pd.isna(v) else ""
 
     def highlight_null(self, null_color="red"):
         """
@@ -1126,9 +1118,7 @@ def relative_luminance(rgba):
             def css(rgba):
                 dark = relative_luminance(rgba) < text_color_threshold
                 text_color = "#f1f1f1" if dark else "#000000"
-                return "background-color: {b};color: {c};".format(
-                    b=colors.rgb2hex(rgba), c=text_color
-                )
+                return f"background-color: {colors.rgb2hex(rgba)};color: {text_color};"
 
             if s.ndim == 1:
                 return [css(rgba) for rgba in rgbas]
@@ -1160,7 +1150,7 @@ def set_properties(self, subset=None, **kwargs):
         >>> df.style.set_properties(color="white", align="right")
         >>> df.style.set_properties(**{'background-color': 'yellow'})
         """
-        values = ";".join("{p}: {v}".format(p=p, v=v) for p, v in kwargs.items())
+        values = ";".join(f"{p}: {v}" for p, v in kwargs.items())
         f = lambda x: values
         return self.applymap(f, subset=subset)
 
@@ -1191,12 +1181,9 @@ def css_bar(start, end, color):
             if end > start:
                 css += "background: linear-gradient(90deg,"
                 if start > 0:
-                    css += " transparent {s:.1f}%, {c} {s:.1f}%, ".format(
-                        s=start, c=color
-                    )
-                css += "{c} {e:.1f}%, transparent {e:.1f}%)".format(
-                    e=min(end, width), c=color
-                )
+                    css += f" transparent {start:.1f}%, {color} {start:.1f}%, "
+                e = min(end, width)
+                css += f"{color} {e:.1f}%, transparent {e:.1f}%)"
             return css
 
         def css(x):
@@ -1358,7 +1345,7 @@ def _highlight_extrema(data, color="yellow", max_=True):
         """
         Highlight the min or max in a Series or DataFrame.
         """
-        attr = "background-color: {0}".format(color)
+        attr = f"background-color: {color}"
 
         if max_:
             extrema = data == np.nanmax(data.to_numpy())
@@ -1528,16 +1515,13 @@ def _maybe_wrap_formatter(formatter, na_rep: Optional[str]):
     elif callable(formatter):
         formatter_func = formatter
     else:
-        msg = (
-            "Expected a template string or callable, got {formatter} "
-            "instead".format(formatter=formatter)
-        )
+        msg = f"Expected a template string or callable, got {formatter} " "instead"
         raise TypeError(msg)
 
     if na_rep is None:
         return formatter_func
     elif isinstance(na_rep, str):
         return lambda x: na_rep if pd.isna(x) else formatter_func(x)
     else:
-        msg = "Expected a string, got {na_rep} instead".format(na_rep=na_rep)
+        msg = f"Expected a string, got {na_rep} instead"
         raise TypeError(msg)