Revert "add iso-format support to to_timedelta"

This reverts commit 3f5f176.

Author: fjdiod

pandas/_libs/tslibs/timedeltas.pyx

@@ -183,10 +183,7 @@ cpdef convert_to_timedelta64(object ts, object unit):
             ts = cast_from_unit(ts, unit)
             ts = np.timedelta64(ts)
     elif is_string_object(ts):
-        if len(ts) > 0 and ts[0] == 'P':
-            ts = np.timedelta64(parse_iso_format_string(ts))
-        else:
-            ts = np.timedelta64(parse_timedelta_string(ts))
+        ts = np.timedelta64(parse_timedelta_string(ts))
     elif hasattr(ts, 'delta'):
         ts = np.timedelta64(delta_to_nanoseconds(ts), 'ns')
 

pandas/io/json/table_schema.py

@@ -6,7 +6,7 @@
 import warnings
 
 import pandas._libs.json as json
-from pandas import DataFrame, to_timedelta
+from pandas import DataFrame, Timedelta
 from pandas.api.types import CategoricalDtype
 import pandas.core.common as com
 from pandas.core.dtypes.common import (
@@ -308,7 +308,7 @@ def parse_table_schema(json, precise_float):
 
     for col, dtype in dtypes.items():
         if dtype == 'timedelta64[ns]':
-            df[col] = to_timedelta(df[col])
+            df[col] = df[col].apply(Timedelta)
 
     df = df.astype(dtypes)