store outputs of loop as dictionary - counting lines of all csv files in folder

onionbag 0
Viewed 36

Ran a loop that counted the number of rows of all .csv files in a folder. I now need to save these results to a dictionary.

import os

for filename in os.listdir(path):
    with open(filename, 'r', encoding="latin-1") as fileObj:
        if filename.endswith('csv'):
            print('Rows counted {} in the csv {}'.format(len(fileObj.readlines()) -1, filename))

I get an output of what I want, but any way I try to save it to a dict results in "I/0 operation closed on file." (I am relatively new sorry if this is a dumb question)

Blockquote

Output:

Rows counted 840593 in the csv MA_2019_01.csv

Rows counted 818861 in the csv MA_2019_02.csv

Rows counted 914653 in the csv MA_2019_03.csv

Rows counted 1011374 in the csv MA_2019_04.csv

Rows counted 1088294 in the csv MA_2019_05.csv

Rows counted 1120696 in the csv MA_2019_06.csv

Rows counted 1119932 in the csv MA_2019_07.csv

Rows counted 1194284 in the csv MAg_2019_08.csv

Rows counted 1136953 in the csv MA_2019_09.csv

Rows counted 1010777 in the csv MA_2019_10.csv

Rows counted 901468 in the csv MA_2019_11.csv

Rows counted 950661 in the csv MA_2019_12.csv

csv dictionary loops python
2 Answers
  1. Whether it is better to check the csv file before opening the file, why open unnecessary ones?
  2. It seems to me that it is more clear when not the length is calculated, but the sum of the lines.
  3. We add elements to the dictionary in a loop. I took the filename without the extension as the key.
import os


dict_count = dict()

for file in os.listdir(r'path'):
    if file.endswith('csv'):
        with open(file, 'r', encoding="latin-1") as f:
            line_count = sum(1 for line in f.readlines()) - 1
        file_name = os.path.splitext(file)[0]
        dict_count[file_name] = line_count
print(dict_count)
Сергей Кох0

You can do this in a single dict comprehension :

import os

file_counts = {
    filename: len(open(filename, "r").readlines()) - 1
    for filename in os.listdir(path)
    if filename.endswith(".csv")
}
ticster0
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