텍스트 파일 (4월 16일)

open() : 열기

• 'w' - 쓰기 전용 (파일이 이미 있으면 덮어씌움)
• 'a' - 쓰기 전용 (파일이 이미 있으면 덧붙임)
• 'x' - 쓰기 전용 (파일이 이미 있으면 에러 발생)
• 'r' - 읽기 전용 (파일이 없으면 에러 발생)

read() : 읽기

• 무조건 문자열로 읽음

write() : 쓰기

close() : 닫기

• with ~ as 문을 이용하면 파일 닫기를 생략할 수 있음

writelines()

• 리스트 또는 튜플 데이터를 파일에 쓰기 위한 함수

readline, readlines()

• readlines : 파일의 모든 데이터를 읽어서 리스트 형태로 반환
• readline : 한 행을 읽어서 문자열로 반환

34

<write>

file = open("/Users/song-yeongseog/Desktop/PYTHON/textfile/test.txt", "w")

strCount = file.write("Hello python!")
print(f"strCount: {strCount}")

file.close()


<실습>

import time

lt = time.localtime()
dateStr = "[" + str(lt.tm_year) + "년" + str(lt.tm_mon) + "월" + str(lt.tm_mday) + "일]"

todaySchedule = input("오늘 일정: ")

file = open("/Users/song-yeongseog/Desktop/PYTHON/textfile/test.txt", "w")
file.write(dateStr + todaySchedule)
file.close()

35

<read>

file = open("/Users/song-yeongseog/Desktop/PYTHON/textfile/test.txt", "r")

str = file.read()
print(f"str: {str}")

file.close()


<실습>

file = open("/Users/song-yeongseog/Desktop/PYTHON/textfile/about_python.txt", "r")
str = file.read()
print(f"str: {str}")
file.close()

str = str.replace("Python", "파이썬", 2)
print(f"str: {str}")

file = open("/Users/song-yeongseog/Desktop/PYTHON/textfile/about_python.txt", "w")
file.write(str)
file.close()

36

url = "/Users/song-yeongseog/Desktop/PYTHON/textfile/"

<w 파일모드>
file = open(url + "hello.txt", "w")
file.write("Hello world!!")
file.close()

<a 파일모드>
file = open(url + "hello.txt", "a")
file.write("\nNice to meet you!!")
file.close()

<x 파일모드>
file = open(url + "hello_01.txt", "x")
file.write("Hello world!!")
file.close()

<w 파일모드>
file = open(url + "hello.txt", "r")
str = file.read()
print(str)
file.close()


<실습>

url = "/Users/song-yeongseog/Desktop/PYTHON/textfile/"

def primeNumber(n):
    file = open(url + "prime_numbers.txt", "a")
    file.write(str(n))
    file.write("\n")
    file.close()

inputNumber = int(input("0보다 큰 정수 입력: "))
for number in range(2, (inputNumber+1)):
    flag = True
    for n in range(2, number):
        if number % n == 0:
            flag = False
            break

    if flag:
        primeNumber(number)

37

<with ~ as>

url = "/Users/song-yeongseog/Desktop/PYTHON/textfile/"

file = open(url + "5_037.txt", "a")
file.write("python study")
file.close()

file = open(url + "5_037.txt", "r")
print(file.read())
file.close()

with open(url + "5_037.txt", "a") as f:
    f.write("python study")

with open(url + "5_037.txt", "r") as f:
    print(f.read())


<실습>

import random

url = "/Users/song-yeongseog/Desktop/PYTHON/textfile/"

def writeNumbers(nums):
    for idx, num in enumerate(nums):
        with open(url + "lotto.txt", "a") as f:
            if idx < (len(nums) - 2):
                f.write(str(num) + ", ")
            elif idx == (len(nums) - 2):
                f.write(str(num))
            elif idx == (len(nums) - 1):
                f.write("\n")
                f.write("bonus: " + str(num))
                f.write("\n")

rNums = random.sample(range(1, 46), 7)
print(f"rNums: {rNums}")

writeNumbers(rNums)

38

<writelines()>

languages = ["c/c++", "java", "c#", "python", "javascript"]

url = "/Users/song-yeongseog/Desktop/PYTHON/textfile/"
for item in languages:
    with open(url + "languages.txt", "a") as f:
        f.write(item)
        f.write("\n")


languages = ["c/c++", "java", "c#", "python", "javascript"]

url = "/Users/song-yeongseog/Desktop/PYTHON/textfile/"
with open(url + "languages.txt", "a") as f:
    f.writelines(item + "\n" for item in languages)

with open(url + "languages.txt", "r") as f:
    print(f.read())

<실습>

url = "/Users/song-yeongseog/Desktop/PYTHON/textfile/"

scoreDic = {"kor": 85, "eng": 90, "mat": 92, "sci": 79, "his": 82}

for key in scoreDic.keys():
    with open(url + "scoreDic.txt", "a") as f:
        f.write(key + "\t: " + str(scoreDic[key]) + "\n")

<실습_scoreDic 그대로 쓰고자 할 때>

scoreDic = {"kor": 85, "eng": 90, "mat": 92, "sci": 79, "his": 82}
with open(url + "scores.txt", "a") as f:
    print(scoreDic, file=f)

39

<readlines()>

url = "/Users/song-yeongseog/Desktop/PYTHON/textfile/"

with open(url + "lans.txt", "r") as f:
    lanList = f.readlines()

print(f"lanList: {lanList}")
print(f"lanList type: {type(lanList)}")


<readline()>

url = "/Users/song-yeongseog/Desktop/PYTHON/textfile/"

with open(url + "lans.txt", "r") as f:
    line = f.readline()

    while line != "":
        print(f"line: {line}", end="")
        line = f.readline()


<실습>

scoreDic = {}

url = "/Users/song-yeongseog/Desktop/PYTHON/textfile/"
with open(url + "score.txt", "r") as f:
    line = f.readline()

    while line != "":
        tempList = line.split(":")
        scoreDic[tempList[0]] = int(tempList[1].strip("\n"))
        line = f.readline()

print(f"scoreDic: {scoreDic}")

자료출처: 제로베이스 데이터 스쿨