文件操作的过程
1）打开
2）操作
3）关闭
1.写(清空写入)
# f = open(file='test', mode='w', encoding='utf-8') # 第一种情况 # f.write("Hello World!") # f.close() # f = open(file='test', mode='wb') # 第二种情况 # f.write("杨".encode('utf-8')) # f.close() # with open(file='test', mode='w', encoding='utf-8') as f: # 第三种情况 # f.write("高圆") with open(file='test', mode='wb') as f1: # 第四种情况 f1.write("李璐".encode('utf-8'))
2.读
# 读 # f = open(file='test', mode='r', encoding='utf-8') # data = f.read() # print(data) # f.close() # f = open(file='test', mode='rb') # data = f.read() # print(data.decode('utf-8')) # f.close() # with open(file='test', mode='r', encoding='utf-8') as f1: # data = f1.read() # print(data) with open(file='test', mode='rb') as f1: data = f1.read().decode('utf-8') print(data)
3.追加写入
# 追加 # f = open(file='test', mode='a', encoding='utf-8') # f.write(' What?') # f.close() # f = open(file='test', mode='ab') # f.write(" tom".encode('utf-8')) # f.close() # with open(file='test', mode='a', encoding='utf-8') as f1: # f1.write(" Hi") with open(file='test', mode='ab') as f1: f1.write(' joker'.encode('utf-8'))
4.读写
# 读写 # f = open(file='test', mode='r+', encoding='utf-8') # data = f.read() # print(data) # f.write(" ok") # f.close() # f = open(file='test', mode='r+b') # data = f.read().decode('utf-8') # print(data) # f.write(' fun'.encode('utf-8')) # f.close() # with open(file='test', mode='r+', encoding='utf-8') as f1: # data = f1.read() # print(data) # f1.write(" fine") with open(file='test', mode='r+b') as f1: data = f1.read().decode('utf-8') print(data) f1.write(' sad'.encode('utf-8'))
5.清空写读
# 清空写读 # f = open(file='test', mode='w+', encoding='utf-8') # f.write("blue") # f.seek(0) # data = f.read() # print(data) # f = open(file='test', mode='w+b') # f.write("joker".encode('utf-8')) # f.seek(0) # data = f.read().decode('utf-8') # print(data) # with open(file='test', mode='w+', encoding='utf-8') as f1: # f1.write("Hello World!") # f1.seek(0) # data = f1.read() # print(data) with open(file='test', mode='w+b') as f1: f1.write("Thank you!".encode('utf-8')) f1.seek(0) data = f1.read().decode('utf-8') print(data)
6.追加写读
# 追加写 # f = open(file='test', mode='a+', encoding='utf-8') # f.write(" tom") # f.seek(0) # data = f.read() # print(data) # f = open(file='test', mode='a+b') # f.write(" tom".encode('utf-8')) # f.seek(0) # data = f.read().decode('utf-8') # print(data) # with open(file='test', mode='a+', encoding='utf-8') as f1: # f1.write(" joker") # f1.seek(0) # data = f1.read() # print(data) with open(file='test', mode='a+b') as f1: f1.write(" tom".encode('utf-8')) f1.seek(0) data = f1.read().decode('utf-8') print(data)
7.常用方法
1）read(n)
光标位置m，读取从m->m+n，n个字符
2）seek(n)
设置光标的位置，n为字节（从0开始）
3）tell()
获取当前光标的位置，单位是字节
with open(file='test1', mode='r+', encoding='utf-8') as f: f.seek(3) # 设置光标位置，字节 data = f.read(2) # 读取，字符 a = f.tell() # 获取光标位置，字节 print(data, ' ', a)
4）按行读取
a.for循环
with open(file='test1', mode='r+', encoding='utf-8') as f: for line in f: print(line)
b.readlines
readlines()，打印的是list，一行作为一个元素
with open(file='test1', mode='r+', encoding='utf-8') as f: data = f.readlines() print(data)
c.readline()
读取一行
with open(file='test1', mode='r+', encoding='utf-8') as f: data = f.readline() print(data)
d.truncate(n)
n为空时，从当前位置截断
n不为空时，从n开始截断（n后的内容舍弃）
n为字节
with open(file='test', mode='w', encoding='utf-8') as f: f.write("你好，之华，之南") f.truncate(6)