Python 技术点

1、文件操作

1-1 遍历文件夹和文件

import os
rootDir = "/path/to/root"

for parent, dirnames, filenames in os.walk(rootDir):
    for dirname in dirnames:
        print("parent is:" + parent)
        print("dirname is:" + dirname)
    
    for filename in filenames:
        print("parent is:" + parent)
        print("filename is:" + filename)
        print("the full name of the file is:" + os.path.join(parent, filename))

1-2 获取文件名和扩展名

import os
path = "/root/to/filename.txt"

name, ext = os.path.splitext(path)
print(name, ext)
print(os.path.dirname(path))
print(os.path.basename(path))

1-3 逐行读取文本文件内容

f = open("/path/to/file.txt")

# The first method
line = f.readline()
while line:
    print(line)
    line = f.readline()
f.close()

# The second method
for line in open("/path/to/file.txt"):
    print(line)

# The third method
lines = f.readlines()
for line in lines:
    print(line)

1-4 写文件

output = open("/path/to/file", "w")
# output = open("/path/to/file", "w+")

output.write(all_the_text)
# output.writelines(list_of_text_strings)

1-5 判断文件是否存在

import os

os.path.exists("/path/to/file")
os.path.exists("/path/to/dir")

# Only check file
os.path.isfile("/path/to/file")

1-6 创建文件夹

import os

# Make multilayer directorys
os.makedirs("/path/to/dir")

# Make single directory
os.makedir("/path/to/dir")

2、其他

2-1 数字前补 0

n = 123
m = -123

print(str(n).zfill(5))    # '00123'
print(str(m).zfill(5))    # '-0123'

print('%05d' % n)    # '00123'
print('%05d' % m)    # '-0123'

（未完待续）