I am trying to modify .csv files in a folder. The files contain flight information from years 2011-2016.
However, year information cannot be found in the values.
I would like to solve this by using the filename of the .csv file which contains the year. I am adding a new 'year' column after reading it into a pandas dataframe. I will then export the modified file to a new .csv with only the year as its filename.
However, I am encountering this error:
ValueError:Length of values does not match length of index
Code below for your reference.
import pandas as pd
import glob
import re
import os
path = r'data_caap/'
all_files = glob.glob(os.path.join(path, "*.csv"))
for f in all_files:
df = pd.read_csv(f)
year= re.findall(r'\d{4}', f)
#Error here
df['year']=year
#Error here
df.to_csv(year)
Found the cause of the error.
Must be df['year']=year[0]. findall returns a list. – DyZ
Thanks a lot @Dyz
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