Python: How to continue loop over many csv if file does not exist

Question

I am looping over many files in folder A and folder B to do some operations on the merged data frame of A_file1 and B_file1; A_file2 and B_file2 etc.

for a in A_list:
     for b in B_list:
         A_file = pd.read_csv(f'A_file{a}.csv')
         B_file = pd.read_csv(f'B_file{b}.csv')
         new_file = pd.merge(A_file, B_file, on="common_var", how='left')
         new_file.to_csv(f'new_file{a}_{b}.csv')

How do I make the loop continue if either A_file or B_file does not exist for a particular {a} or {b}? (And just not create an {a}_{b} file if either {a} or {b} does not exist?)

Are you getting an error when you encounter files that do not exist? If so, please include the stacktrace. — PacketLoss
– PacketLoss, Commented Feb 3, 2020 at 3:51
You could use a Try/Catch block as done in this exaple reading CSV into Dataframes — DarrylG
– DarrylG, Commented Feb 3, 2020 at 3:56

Sameeresque · Accepted Answer · 2020-02-03 03:56:02Z

1

You could use try/except like so:

for a in A_list:
    for b in B_list:
        try:
            A_file = pd.read_csv(f'A_file{a}.csv')
            B_file = pd.read_csv(f'B_file{b}.csv')
            new_file = pd.merge(A_file, B_file, on="common_var", how='left')
            new_file.to_csv(f'new_file{a}_{b}.csv')
        except:
            print ("Either file A or file B is missing")

answered Feb 3, 2020 at 3:56

Sameeresque

2,6022 gold badges14 silver badges24 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Dishin Goyani Over a year ago

Should use specific exception - except FileNotFoundError: #...

Collectives™ on Stack Overflow

Python: How to continue loop over many csv if file does not exist

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related