Rewrite how string is formatted (for backwards compatibility)

Marco Gorelli · Marco Gorelli · commit 556adb2a7a01 · 2019-08-29T16:30:53.000+01:00
diff --git a/pandas/core/frame.py b/pandas/core/frame.py
@@ -6246,7 +6246,7 @@ def explode(self, column: Union[str, Tuple]) -> "DataFrame":
 
         if isinstance(self.index, MultiIndex):
             index_names = [
-                f"level_{num}" if val is None else val
+                "level_{num}".format(num=num) if val is None else val
                 for num, val in enumerate(self.index.names)
             ]
         else:

Original file line number	Diff line number	Diff line change
`@@ -6246,7 +6246,7 @@ def explode(self, column: Union[str, Tuple]) -> "DataFrame":`
`6246`	`6246`
`6247`	`6247`	`if isinstance(self.index, MultiIndex):`
`6248`	`6248`	`index_names = [`
`6249`		`- f"level_{num}" if val is None else val`
	`6249`	`+ "level_{num}".format(num=num) if val is None else val`
`6250`	`6250`	`for num, val in enumerate(self.index.names)`
`6251`	`6251`	`]`
`6252`	`6252`	`else:`