Software Engineer English & Software Engineering Blog - Sean

Python 기본 라이브러리 csv를 이용해 CSV(comma-separated values) 형식을 분석할 수 있다.

import locale
import csv

lo = locale.getdefaultlocale()
# Tries to determine the default locale settings and returns them as a tuple of
# the form (language code, encoding).
print("Default language code: " + lo[0], "Default encoding: " + lo[1], sep = "\n", end = "\n\n")

filename = "list.csv"
with open(filename, "rt", encoding="euc_kr") as f:
    csv_data = f.read()

data = []
rows = csv_data.split("\n")
for row in rows:
    if row == "":
        continue
    cells = row.split(",")
    data.append(cells)

for c in data:
    print("%-8s %8s" %(c[1], c[2]))

print()

#Python csv library
with open(filename, "at", encoding="euc_kr") as f:
    # 'a' - open for writing, appending to the end of the file if it exists
    # For binary read-write access, the mode 'w+b' opens and truncates the file to 0 bytes.
    # 'r+b' opens the file without truncation.
    csv_writer = csv.writer(f, delimiter = ",", quotechar = '"')
    csv_writer.writerow(["101", "Math", "4300"])
    csv_writer.writerow(["102", "Physics", "4800"])    
    csv_writer.writerow(["103", "English", "5700"])
# stream position을 바꾸고 싶으면 io module의 seek()을 f.seek(...)처럼 사용 한다.
# seek(offset[, whence])
# Change the stream position to the given byte offset. offset is interpreted relative to the
# position indicated by whence. The default value for whence is SEEK_SET. Values for whence are:
# SEEK_SET or 0 – start of the stream (the default); offset should be zero or positive
# SEEK_CUR or 1 – current stream position; offset may be negative
# SEEK_END or 2 – end of the stream; offset is usually negative
# Return the new absolute position.

with open(filename, "rt", encoding="euc_kr") as f:
    csv_reader = csv.reader(f, delimiter = ",", quotechar = '"')
    for cells in csv_reader:
        if cells == []:
            continue
        print("%-8s %8s" %(cells[1], cells[2]))

list.csv:

결과:

실행 후 list.csv: