/python-snippet

Collection of useful Python snippets that you can understand in 30 seconds or less.

Date

Datetime

from datetime import datetime, timedelta

DATE_FORMAT = '%Y%m%d'
# show today with yyyymmdd format by string format time func
TODAY = datetime.today().strftime(DATE_FORMAT)

# convert string datetime to date obj by string parse time func
datetime_obj = datetime.strptime('20170111', DATE_FORMAT)

File operation

Delete file

Delete a file which may not exist.

import os

try:
    os.remove(filename)
except OSError:
    pass

Check file exist

import os

if os.path.exists(path):
    print ('File exist')

Use glob to iterate file that match a specified pattern

import glob

files = glob.glob('/path/to/files/*.txt')

for f in file:
    print(f)

List operation

Two lists substraction

  • Using set to subtract two list.
list(set(origin_all_feature_list) - set(remove_nan_feature_list))

Pandas

Import data

import pandas as pd

path = 'data.csv'

### Import data without first column as header
data = pd.read_csv(path, header=None)

print data