PERF: consolidate imports inside parse_time_string (#24084)

Author: qwhelan

asv_bench/benchmarks/period.py

@@ -43,13 +43,17 @@ class PeriodIndexConstructor(object):
  def setup(self, freq):
  self.rng = date_range('1985', periods=1000)
  self.rng2 = date_range('1985', periods=1000).to_pydatetime()
+ self.ints = list(range(2000, 3000))
 
  def time_from_date_range(self, freq):
  PeriodIndex(self.rng, freq=freq)
 
  def time_from_pydatetime(self, freq):
  PeriodIndex(self.rng2, freq=freq)
 
+ def time_from_ints(self, freq):
+ PeriodIndex(self.ints, freq=freq)
+
 
 class DataFramePeriodColumn(object):
 

pandas/_libs/tslibs/parsing.pyx

@@ -118,12 +118,12 @@ def parse_time_string(arg, freq=None, dayfirst=None, yearfirst=None):
  if getattr(freq, "_typ", None) == "dateoffset":
  freq = freq.rule_code
 
- if dayfirst is None:
+ if dayfirst is None or yearfirst is None:
  from pandas.core.config import get_option
- dayfirst = get_option("display.date_dayfirst")
- if yearfirst is None:
- from pandas.core.config import get_option
- yearfirst = get_option("display.date_yearfirst")
+ if dayfirst is None:
+  dayfirst = get_option("display.date_dayfirst")
+ if yearfirst is None:
+  yearfirst = get_option("display.date_yearfirst")
 
  res = parse_datetime_string_with_reso(arg, freq=freq,
  dayfirst=dayfirst,