超詳細(xì)的Python文件操作知識(shí)

f1 = open(r'd:\測試文件.txt', mode='r', encoding='utf-8')content = f1.read()print(content)f1.close()

with open(r'd:\測試文件.txt', mode='r', encoding='utf-8') as f1:    content = f1.read()????print(content)

#優(yōu)點(diǎn)1：不用手動(dòng)關(guān)閉文件句柄。with open('文件操作的讀', encoding='utf-8') as f1:    print(f1.read())
#優(yōu)點(diǎn)2：一個(gè)語句可以操作多個(gè)文件句柄。with open('文件操作的讀', encoding='utf-8') as f1, \        open('文件操作的寫', encoding='utf-8', mode='w') as f2:    print(f1.read())????f2.write('hahaha')

lucy最帥lucy很勵(lì)志abcdef哈哈哈

f1 = open('文件操作的讀', encoding='utf-8')content = f1.read()print(content, type(content))f1.close()
f1 = open(r'C:\Users\lenovo\Desktop\編碼進(jìn)階.png', mode='rb')content = f1.read()print(content)f1.close()

f1 = open('文件操作的讀', encoding='utf-8')content = f1.read(6)print(content)  # lucy最帥f1.close()

f1 = open('文件操作的讀', encoding='utf-8')print(f1.readline().strip())  # lucy最帥print(f1.readline())  # lucy很勵(lì)志\nf1.close()

f1 = open('文件操作的讀', encoding='utf-8')li = f1.readlines()print(li)  # ['lucy最帥\n', 'lucy很勵(lì)志\n', 'abcdef\n', '哈哈哈']f1.close()

f1 = open('文件操作的讀', encoding='utf-8')for line in f1:    print(line.strip())f1.close()

f1 = open('文件操作的寫', encoding='utf-8', mode='w')f1.write('lucy真帥')f1.close()

f1 = open(r'C:\Users\lenovo\Desktop\編碼進(jìn)階.png', mode='rb')content = f1.read()f1.close()
f2 = open('圖片.jpg', mode='wb')f2.write(content)f2.close()

f = open('test.txt')print(f.read(10))  # read 指定讀取的字節(jié)數(shù)print(f.tell())    # tell()方法顯示當(dāng)前文件指針?biāo)诘奈淖?/span>f.close()

f?=?open('test.txt','rb')??#?需要指定打開模式為rb,只讀二進(jìn)制模式print(f.read(3))print(f.tell())f.seek(2,0)   # 從文件的開頭開始，跳過兩個(gè)字節(jié)print(f.read())f.seek(1,1) # 從當(dāng)前位置開始，跳過一個(gè)字節(jié)print(f.read())f.seek(-4,2) # 從文件末尾開始，往前跳過四個(gè)字節(jié)print(f.read())f.close()

import os
file_name = input('請(qǐng)輸入一個(gè)文件路徑:')if os.path.isfile(file_name):    old_file = open(file_name, 'rb')  # 以二進(jìn)制的形式讀取文件
    names = os.path.splitext(file_name)    new_file_name = names[0] + '.bak' + names[1]
    new_file = open(new_file_name, 'wb')  # 以二進(jìn)制的形式寫入文件
    while True:        content = old_file.read(1024)  # 讀取出來的內(nèi)容是二進(jìn)制        new_file.write(content)        if not content:            break
    new_file.close()    old_file.close()else:????print('您輸入的文件不存在')

name,age,scorezhangsan,18,98lisi,20,99wangwu,17,90jerry,19,95

import csv
# 以寫入方式打開一個(gè)csv文件file = open('test.csv','w')
# 調(diào)用writer方法，傳入csv文件對(duì)象，得到的結(jié)果是一個(gè)CSVWriter對(duì)象writer = csv.writer(file)
# 調(diào)用CSVWriter對(duì)象的writerow方法，一行行的寫入數(shù)據(jù)writer.writerow(['name', 'age', 'score'])
# 還可以調(diào)用writerows方法，一次性寫入多行數(shù)據(jù)writer.writerows([['zhangsan', '18', '98'],['lisi', '20', '99'], ['wangwu', '17', '90'], ['jerry', '19', '95']])file.close()

import csv
# 以讀取方式打開一個(gè)csv文件file = open('test.csv', 'r')
# 調(diào)用csv模塊的reader方法，得到的結(jié)果是一個(gè)可迭代對(duì)象reader = csv.reader(file)
# 對(duì)結(jié)果進(jìn)行遍歷，獲取到結(jié)果里的每一行數(shù)據(jù)for row in reader:    print(row)
file.close()

from io import StringIO
# 創(chuàng)建一個(gè)StringIO對(duì)象f = StringIO()# 可以像操作文件一下，將字符串寫入到內(nèi)存中f.write('hello\r\n')f.write('good')
# 使用文件的 readline和readlines方法，無法讀取到數(shù)據(jù)# print(f.readline())# print(f.readlines())
# 需要調(diào)用getvalue()方法才能獲取到寫入到內(nèi)存中的數(shù)據(jù)print(f.getvalue())
f.close()

from io import BytesIO
f = BytesIO()f.write('你好\r\n'.encode('utf-8'))f.write('中國'.encode('utf-8'))
print(f.getvalue())f.close()

import syss_in = sys.stdinwhile True:    content = s_in.readline().rstrip('\n')    if content == '':        break????print(content)

import sysm = open('stdout.txt', 'w', encoding='utf8')sys.stdout = mprint('hello')print('yes')print('good')m.close()

helloyesgood

import sysx = open('stderr.txt', 'w', encoding='utf8')sys.stderr = xprint(1 / 0)x.close()

Traceback (most recent call last):  File "E:/python基礎(chǔ)/demo.py", line 4, in <module>    print(1 / 0)ZeroDivisionError: division by zero

import jsonfile = open('names.txt', 'w')names = ['zhangsan', 'lisi', 'wangwu', 'jerry', 'henry', 'merry', 'chris']# file.write(names)  出錯(cuò)，不能直接將列表寫入到文件里
# 可以調(diào)用 json的dumps方法，傳入一個(gè)對(duì)象參數(shù)result = json.dumps(names)
# dumps 方法得到的結(jié)果是一個(gè)字符串print(type(result))  # 
# 可以將字符串寫入到文件里file.write(result)
file.close()

import json
file = open('names.txt', 'w')names = ['zhangsan', 'lisi', 'wangwu', 'jerry', 'henry', 'merry', 'chris']
# dump方法可以接收一個(gè)文件參數(shù)，在將對(duì)象轉(zhuǎn)換成為字符串的同時(shí)寫入到文件里json.dump(names, file)file.close()

import json
# 調(diào)用loads方法，傳入一個(gè)字符串，可以將這個(gè)字符串加載成為Python對(duì)象result = json.loads('["zhangsan", "lisi", "wangwu", "jerry", "henry", "merry", "chris"]')print(type(result))  # 

import json
# 以可讀方式打開一個(gè)文件file = open('names.txt', 'r')
# 調(diào)用load方法，將文件里的內(nèi)容加載成為一個(gè)Python對(duì)象result = json.load(file)
print(result)file.close()

import picklenames = ['張三', '李四', '杰克', '亨利']b_names = pickle.dumps(names)# print(b_names)file = open('names.txt', 'wb')file.write(b_names)  # 寫入的是二進(jìn)制，不是存文本file.close()

import picklenames = ['張三', '李四', '杰克', '亨利']file2 = open('names.txt', 'wb')pickle.dump(names, file2)file2.close()

import picklefile1 = open('names.txt', 'rb')x = file1.read()y = pickle.loads(x)print(y)file1.close()

import picklefile3 = open('names.txt', 'rb')z = pickle.load(file3)print(z)

import jsonclass MyEncode(json.JSONEncoder):    def default(self, o):        # return {"name":o.name,"age":o.age}        return o.__dict__
class Person(object):    def __init__(self, name, age):        self.name = name        self.age = age
      def eat(self):          print(self.name+'正在吃東西')
p1 = Person('zhangsan', 18)
# 自定義對(duì)象想要轉(zhuǎn)換成為json字符串，需要給這個(gè)自定義對(duì)象指定JSONEncoderresult = json.dumps(p1, cls=MyEncode)print(result)  # {"name": "zhangsan", "age": 18}
# 調(diào)用loads方法將對(duì)象加載成為一個(gè)對(duì)象以后，得到的結(jié)果是一個(gè)字典p = json.loads(result)print(type(p))