acad_hist = [{‘crse_id’: u'GRG 302P0', ‘grade’: u’’}, {‘crse_id’: u’URB 3010', ‘grade’: u’B+‘},
{‘crse_id’: u'GRG 302P0', ‘grade’: u’D‘}]
grade_list = ['CR', 'D-', 'D', 'D+', 'C-', 'C', 'C+', 'B-', 'B', 'B+', 'A-', 'A', 'A+']
At first I tried to loop through the acad_hist list and add any classes not-yet-seen to the “seen” list. It was then the plan that when I come across a class that had already been added to the “seen” list, I should go back to the acad_hist list, grab the details (e.g. "grade") of that class, evaluate the grades, and remove the class with the lower grade from the acad_hist list. Problem is, I’m having a tough time easily going back and “grabbing” the earlier seen class from the “seen” list and even more difficulty correctly pointing to it once I know I need to delete it from the acad_hist list. The code is a mess but here is what I have so far:
key = ‘crse_id’ for index, course in enumerate(acad_hist[:]): if course[key] not in seen: seen.append(course[key]) else: logger.info('found duplicate {0} at index {1}'.format(course[key], index)) < not sure what to do here… >OUTPUT:
found duplicate GRG 302P0 at index 11So then I thought I might be able to use the set() function to cull the list for me, but the problem here is that I need to choose which class instance to keep and set() doesn’t seem to allow me a way to do that.
names = set(d['compressed_hist_crse_id'] for d in acad_hist_condensed) logger.info('TEST names: {0}'.format(names))OUTPUT:
TEST names: set([u'GRG 302P0', u'URB 3010’}]Wanting to see if I could add to #2 above, I thought I’d do some “belt-n-suspenders” looping through the output of the set() “names” and collect a grade. It’s working, but I don’t pretend to fully understand what it’s doing, nor does it really allow me to do the processing I need to do.
new_dicts = [] for name in names: d = dict(name=name) d['grade'] = max(d['grade'] for d in acad_hist if d['crse_id'] == name) new_dicts.append(d) logger.info('TEST new_dicts: {0}'.format(new_dicts))OUTPUT:
TEST new_dicts: [{'grade': u'', 'name': u'GRG 302P0'}, {'grade': u’B’+, 'name': u'URB 3010'}]
有人能为我提供缺失的部分，甚至是更好的方法吗？
更新--我最终采用的解决方案（根据我从被接受的答案中得到的想法进行了改编）
def scrub_for_duplicate_courses(acad_hist_condensed, acad_hist_list):
"""
Looks for duplicate courses that may have been taken, and if any are found, will look for the one with the highest
grade and keep that one, deleting the other course from the lists before returning them.
"""
# -------------------------------------------
# set logging params
# -------------------------------------------
logger = logging.getLogger(__name__)
# -----------------------------------------------------------------------------------------------------
# the grade_list is in order of ascending priority/value...a blank grade indicates "in-progress", and
# will therefore replace any class instance that has a grade.
# -----------------------------------------------------------------------------------------------------
grade_list = ['CR', 'D-', 'D', 'D+', 'C-', 'C', 'C+', 'B-', 'B', 'B+', 'A-', 'A', 'A+', '']
# converting the grade_list in to a more efficient, weighted dict
grade_list = dict(zip(grade_list, range(len(grade_list))))
seen_courses = {}
for course in acad_hist_condensed[:]:
# -----------------------------------------------------------------------------------------------------
# one of the two keys checked for below should exist in the list, but not both
# -----------------------------------------------------------------------------------------------------
key = ''
if 'compressed_hist_crse_id' in course:
key = 'compressed_hist_crse_id'
elif 'compressed_ovrd_crse_id' in course:
key = 'compressed_ovrd_crse_id'
cid = course[key]
grade = course['grade']
if cid not in seen_courses:
seen_courses[cid] = grade
else:
# ---------------------------------------------------------------------------------------------------------
# if we get here, a duplicate course_id has been found in the acad_hist_condensed list, so now we'll want
# to determine which one has the lowest grade, and remove that course instance from both lists.
# ---------------------------------------------------------------------------------------------------------
if grade_list.get(seen_courses[cid], 0) < grade_list.get(grade, 0):
seen_courses[cid] = grade # this will overlay the grade for the record already in seen_courses
grade_for_rec_to_remove = seen_courses[cid]
crse_id_for_rec_to_remove = cid
else:
grade_for_rec_to_remove = grade
crse_id_for_rec_to_remove = cid
# -----------------------------------------------------------------------------------------------------
# find the rec in acad_hist_condensed that needs removal
# -----------------------------------------------------------------------------------------------------
for rec in acad_hist_condensed:
if rec[key] == crse_id_for_rec_to_remove and rec['grade'] == grade_for_rec_to_remove:
acad_hist_condensed.remove(rec)
for rec in acad_hist_list:
if rec == crse_id_for_rec_to_remove:
acad_hist_list.remove(rec)
break # just want to remove one occurrence
return acad_hist_condensed, acad_hist_list