2017-11-29

python

python from future import absolute_import

from future import absolute_import

1.使用以上语句则启动绝对导入

会从 sys.path 里寻找所有名为 x 的顶层模块

2.而相应的相对导入则采用`.`

比如一个 package 下有 a.py 和 b.py 两个文件，在 a.py 里 from . import b 即是相对导入 b.py。

区别

PEP 328中：

package/
    __init__.py
    subpackage1/
        __init__.py
        moduleX.py
        moduleY.py
    subpackage2/
        __init__.py
        moduleZ.py
    moduleA.py

from .moduleY import spam
from .moduleY import spam as ham
from . import moduleY
from ..subpackage1 import moduleY
from ..subpackage2.moduleZ import eggs
from ..moduleA import foo
from ...package import bar
from ...sys import path

一个.表示从当前目录寻找

两个.表示从父目录寻找

更多的.则从更高层级的目录寻找

2017-11-27

mongodb

django models mongoengine not in filter

Django: NOT IN -> exclude(a__in=b_list)

NOT IN: nin

ne – not equal to
lt – less than
lte – less than or equal to
gt – greater than
gte – greater than or equal to
not – negate a standard check, may be used before other operators (e.g. Q(age__not__mod=5))
in – value is in list (a list of values should be provided)
nin – value is not in list (a list of values should be provided)
mod – value % x == y, where x and y are two provided values
all – every item in list of values provided is in array
size – the size of the array is
exists – value for field exists

Offical Docs: Querying the database

2017-11-22

json

check class has attribute

import json
def json_load_byteified(file_handle):
    return _byteify(
        json.load(file_handle, object_hook=_byteify),
        ignore_dicts=True
    )
def json_loads_byteified(json_text):
    return _byteify(
        json.loads(json_text, object_hook=_byteify),
        ignore_dicts=True
    )
def _byteify(data, ignore_dicts = False):
    # if this is a unicode string, return its string representation
    if isinstance(data, unicode):
        return data.encode('utf-8')
    # if this is a list of values, return list of byteified values
    if isinstance(data, list):
        return [ _byteify(item, ignore_dicts=True) for item in data ]
    # if this is a dictionary, return dictionary of byteified keys and values
    # but only if we haven't already byteified it
    if isinstance(data, dict) and not ignore_dicts:
        return {
            _byteify(key, ignore_dicts=True): _byteify(value, ignore_dicts=True)
            for key, value in data.iteritems()
        }
    # if it's anything else, return it in its original form
    return data

Example usage:

>>> json_loads_byteified('{"Hello": "World"}')
{'Hello': 'World'}
>>> json_loads_byteified('"I am a top-level string"')
'I am a top-level string'
>>> json_loads_byteified('7')
7
>>> json_loads_byteified('["I am inside a list"]')
['I am inside a list']
>>> json_loads_byteified('[[[[[[[["I am inside a big nest of lists"]]]]]]]]')
[[[[[[[['I am inside a big nest of lists']]]]]]]]
>>> json_loads_byteified('{"foo": "bar", "things": [7, {"qux": "baz", "moo": {"cow": ["milk"]}}]}')
{'things': [7, {'qux': 'baz', 'moo': {'cow': ['milk']}}], 'foo': 'bar'}
>>> json_load_byteified(open('somefile.json'))
{'more json': 'from a file'}

stackoverflow

2017-11-02

linux

linux grep reg content

grep -P

awk -F”[123]”

1	cat some.log* \| grep -P 'abc.*]' -o \| awk -F'\|' '{print $2}' \| grep -v 0

grep -P切出想要的内容

参考链接

1	awk -F"[@ /t]" '{print $2,$3}' test

以@，空格，Tab键分割test文件的每一行，并输出第二、第三列。

2017-11-02

linux

linux sync folder by rsync

rsync

rsync -avz --delete "/home/user/A" "/home/user/B"

Explanation by SonicARG

-a Do the sync preserving all filesystem attributes

-v run verbosely

-z compress the data during the sync (transport the data in compressed mode)

--delete delete the files in target folder that do not exist in the source, /home/user/A: source folder, /home/user/B: target folder

exclude .git

--exclude='.git/'

How to use rsync to backup a directory without git subdirectory

How to sync two folders with command line tools?

from __future__ import absolute_import