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Python

  • add path dir

    import sys
sys.path.append("../")

  • python np array initialization with value and length

    np.full((3, 5), 7, dtype=int)
array([[7, 7, 7, 7, 7],
      [7, 7, 7, 7, 7],
      [7, 7, 7, 7, 7]])

  • python list initialization with value and length

    u_list = [0] * 10

  • python print same line

    print (word1, end=' ')

  • python time to string

    import time
timestr = time.strftime("%Y%m%d-%H%M%S-%f) # %f: micro second

  • Comparing a string to multiple items in Python

    accepted_strings = {'auth', 'authpriv', 'daemon'}
if facility in accepted_strings:
    do_stuff()
    • python np array initialization with value and length 
      np.full((3, 5), 7, dtype=int)
array([[7, 7, 7, 7, 7],
      [7, 7, 7, 7, 7],
      [7, 7, 7, 7, 7]])

  • python으로 http 파일 서버 열기

    python3 -m http.server 3333

  • python runtime timestamp print

    import time
start_time = time.time()
main()
print("--- %s seconds ---" % (time.time() - start_time))

  • 문자열에서 특수문자 지우기 (string)

    import re
text = u'010-1566#7152'
parse = re.sub('[-=.#/?:$}]', '', text)
print parse

  • Handling missing keys in Python dictionaries

    • get(key, default_value) 함수를 활용하여 해결
    • body_position_info라는 key에 해당하는 값이 있으면, return해주고, 아니면 -1을 리턴
    if output_data.get('body_position_info', -1) == -1:
  continue

  • 변수의 type 검사 (아래 예는 str인지)

    if isinstance(variable, str):

JSON

  • JSONDecodeError:

    • json_str = json.loads(jsonString, strict=False)
    • If strict is false (True is the default), then control characters will be allowed inside strings. Control characters in this context are those with character codes in the 0–31 range, including '\t' (tab), '\n', '\r' and '\0'.

  • UnicodeDecodeError: 'utf8' codec can't decode byte

    • str = unicode(str, errors='replace')
    • str = unicode(str, errors='ignore')

  • Json file open

    import json
with open('data.json') as f:
  data = json.load(f)
print(data)

JSONL (JSON Line)

  • python -m pip install json-lines 
    import json_lines

with open('fileName.jsonl', 'rb') as f: # opening file in binary(rb) mode    
  for item in json_lines.reader(f):
    print(item) #or use print(item['X']) for printing specific data
    • 이유는 모르겠지만, no module named 'json_lines' 에러가 난다. 따라서 그냥 파일을 읽고 라인 단위로 json.load를 해서 list에 결과를 append 하는 식으로 했다..

pymongo (mongodb)

  • ModuleNotFoundError: No module named 'pymongo' # pymongo 설치하기 
    pip install pymongo
  • mongodb find in python 
    import pymongo

myclient = pymongo.MongoClient("mongodb://localhost:27017/")
mydb = myclient["mydatabase"]
mycol = mydb["customers"]

x = mycol.find_one()

print(x)
  • mongodb find with for loop 
    _db = _client["_db_name"]
_col = _db["_collection_name"]
for doc in _col.find():
  print (doc)

zmq

  • bind -> connect로 바꿨을 때 생기는 오류 
    File "zmq/backend/cython/socket.pyx", line 580, in zmq.backend.cython.socket.Socket.connect
File "zmq/backend/cython/checkrc.pxd", line 25, in zmq.backend.cython.checkrc._check_rc
zmq.error.ZMQError: Invalid argument
    • *를 못씀