Python常用命令

1. 常用命令

1.1 字符串

s.rfind('l') # if s = "hello", then this expression returns 3
"123".isdigit()

1.2 文件系统

import os, sys
os.makedirs(r"E:/a/b/", exist_ok=True)
BASE_DIR = os.path.dirname(os.path.abspath(__file__))
abosulte_path = os.path.join(dir_path, filename)
if not os.path.exists(folder_path):
    os.
filenames = os.listdir(dir_path)
os.path.mkdirs(dir_path, exist_ok=True)
os.path.isdir(one_path)
os.path.isfile(one_path)
os.path.basename(one_path)
os.path.dirname(one_path)
os.remove(one_path)

files = glob.glob("./*/*_pose/*.pose")

1.3 格式化输出

print("this is a string", flush=True)

1.4 类型判定

dataset = dataset if isinstance(dataset, (list, tuple)) else [dataset]

1.5 循环遍历

for i, (k, v) in enumerate(zip(names, values))
for k, v in zip(names, values)

1.6 numeric

sys.float_info.min # 2.2250738585072014e-308
sys.float_info.max # 1.7976931348623157e+308
float('inf')
float('nan')

1.7 文件读写

with open(filename, "w") as fout:
    print(" ".join(map(str， data)), file=fout)
    fout.flush()

1.8 Error/Exception

raise ValueError("The {} does not exist".format(filename))

1.9 系统命令调用

# demo 1
if not os.path.exists(data_dir):
    www = 'https://modelnet.cs.princeton.edu/ModelNet40.zip'
    zipfile = os.path.basename(www)
    os.system('wget %s; unzip %s' % (www, zipfile))
    os.system('mv %s %s' % (zipfile[:-4], base_dir))
    os.system('rm %s' % (zipfile))
# demo 2
import subprocess
args = "./3DSmoothNet -f " + point_cloud_files[i] + " -k " + keypoints_files[i] + " -o ./data/demo/sdv/"
subprocess.call(args, shell=True)

1.10 Setup

python3 setup.py install

2. 样例代码片段