namwan_data.py

import csv

csvfiles = {
    'ACRU': 'ACRU.csv',
    'ANLI': 'ANLI.csv',
    'BBUA': 'BBUA.csv'
}
data = {}

for key, filename in csvfiles.items():
    with open('ACRU.csv', newline='') as csvfile:
        measure_values = csv.reader(csvfile, delimiter=',')
        first = True
        for row in measure_values:
            if first:
                first = False
                continue

            year, month, day, time, rain = row
            if data.get(f'{year}-{month}-{day}') is None:
                data[f'{year}-{month}-{day}'] = []

            row.append(key)
            data[f'{year}-{month}-{day}'].append(row)
 
for key, day_data in data.items():
    with open(f'output/{key}.csv', 'w', newline='') as f:
        writer = csv.writer(f, delimiter=',')
        # header
        writer.writerow(['year','month','day','time','rain', 'station'])
        
        for row in day_data:
            writer.writerow(row)