使用python或unix比较文件的两列

Question

I have data in a file like csv, or a txt file with a specific seperator. for example:

date|Symbol
2017-05-01|A
2017-05-01|B
2017-05-01|C
2017-05-01|A
2017-05-02|A
2017-05-02|B
2017-05-02|C
2017-05-03|A
2017-05-04|A
2017-05-04|B
2017-05-04|C
2017-05-05|A
2017-05-05|A
2017-05-05|B
2017-05-06|C
2017-05-06|A
2017-05-07|A
2017-05-05|B
2017-05-07|C
2017-05-08|A

Now I want to check if any symbol is getting repeated on a particular day,and if yes, then the symbol with date. Like Symbol A is getting repeat on 01-May, B is on 05-May.

I am trying to do it by using python, that Putting all Symbols in a list, and then check it over column one if any date is getting repeated.

Is there any other solutions than this.

Answer 1

Read line by line then split by pipe |:

ln.split("|")[1]

This will show characters like AB ...

Compare this with others

Answer 2

With python difflib https://pymotw.com/2/difflib/

import difflib
from difflib_data import *

d = difflib.Differ()
diff = d.compare(text1_lines, text2_lines)
print '\n'.join(diff)

Answer 3

I have created a list of dictionaries and each dictionary have key as data and list of column 2 as a value. now i checked in every dictionary if any thing is repeating.

If any one have better solution than this, then it is most welcome.

Updating implementation code for above:

with open(file_path,"rb") as f:
    reader = csv.reader(f,delimiter=delmtr)
    for line in reader:
        if is_header == 1:
            is_header = 0
            continue
        date_dict = {}
        inst_fl_col = inst_col - 1
        date_fl_col = date_col - 1
        if line[date_fl_col] not in date_list:
            date_list.append(line[date_fl_col])
            instrument_list = []
            instrument_list.append(line[inst_fl_col])
            date_dict[line[date_fl_col]] = instrument_list
            p_list.append(date_dict)
            csvwriter.writerow(line)
            del date_dict,instrument_list
        else:
            for dicts in p_list:
                for k,v in dicts.items():
                    if k == line[date_fl_col]:
                        if line[inst_fl_col] not in v:
                            v.append(line[inst_fl_col])
                            csvwriter.writerow(line)
                        else:
                            count += 1
nw_fl.close()
print str(count)+" rows ignored in newly created "+new_file_name+" file"
del date_list[:],is_header,csvwriter,count

I did it by using basic knowledge of python, now i'm improving this using collections module and defaultdict class. Please let me know if any one require the improved code.

Suggestion are most welcome.