文件读写（i/o）

做文件读取的时候该怎么去读?
打开文件

file = open("n.txt", encoding="utf-8")

读取内容

read() #读取全文
readline() #每行读取
readlines() # 读取所有行，把读取的文件按行拆分转为list存放，遍历list输出每一行

关闭文件

file.close()

1.打开文件

file = open("n.txt", encoding="utf-8")

2.文件指针所在位置获取

file.tell()

3.按行读取

file.readline()

3.按行读取，去掉收尾空格

file.readline().strip()

4.跳转到文件指针所在位置
file.seek(19)

5.遍历文件的方式，全部读取并且转为list

for line in file.readlines():
    print("line::", line.strip())

6.遍历文件的方式，逐行读取进行操作，不会提前加载到内存中，可以解决性能问题

for line in file:
    print("line::", line.strip())

7.关闭文件

file.close()

8.写入数据

file.write(string)

data = "天琴座1
"
file1.write(data)
file1.write(data)
l1 = ["xiaohei", "xiaobai", "xiaohong", "xiaoming"]
file1.writelines(l1)
for l in l1:
    file1.write(l)
    file1.write("
")

9.覆盖模式写入

file1 = open("a.txt", "w", encoding="utf-8")

file1 = open("a.txt", "w", encoding="utf-8")#新增文件，写入模式
data = "天琴座1
"
file1.write(data)#写入data的值
file1.write(data)
l1 = ["xiaohei", "xiaobai", "xiaohong", "xiaoming"]
file1.writelines(l1) #写入l1的值
for l in l1:
    file1.write(l)
    file1.write("
")#换行
file1.close()

9.追加模式写入

file2 = open("a.txt", "a", encoding="utf-8")

file2 = open("a.txt", "w", encoding="utf-8")#新增文件，追加模式
data = "天琴座1
"
file2.write(data)#写入data的值
file2.write(data)
l1 = ["xiaohei", "xiaobai", "xiaohong", "xiaoming"]
file2.writelines(l1) #写入l1的值
for l in l1:
    file2.write(l)
    file2.write("
")#换行
file2.close()