Nyahua

# coding: utf-8

# In[31]:

dict_list = [
    {'id': 1, 'key1': 'abc'},
    {'id': 2, 'key1': 'def', 'key2': 123},
    {'id': 3, 'key1': 'ghi', 'key2': 456, 'children': [
        {'id': 4, 'key1': 'jkl'},

Nyahua

What is the difference between json.dumps and json.load? [closed]

dumps takes an object and produces a string:

>>> a = {'foo': 3}
>>> json.dumps(a)
'{"foo": 3}'

load would take a file-like object, read the data from that object, and use that string to create an object:

Nyahua

[How to remove a directory from git repository] (http://stackoverflow.com/questions/6313126/how-to-remove-a-directory-from-git-repository)

Remove directory from git and local

git rm -r one-of-the-directories
git commit -m "Remove duplicated directory"
git push origin <your-git-branch> (typically 'master', but not always)

Remove directory from git but NOT local

Nyahua

http://askubuntu.com/questions/396654/how-to-run-the-python-program-in-the-background-in-ubuntu-machine

Use no hangup to run a program in background even if you close your terminal.

nohup Python server.py &

Now to show it when it's in the background, type:

ps aux | grep "server.py"

Nyahua

I got a wrong log as:

test_string = """
03/27/17 12:55.23something wrong with 20405 post id 450469503/27/17 12:50.55something
wrong with 20302 post id 450180903/27/17 11:41.18something wrong with 18314 
post id 443624203/27/17 11:26.56something wrong with 17922 post id 442210904/27/17 10:48.33
something wrong with 16775 post id 438259104/27/17 10:30.59something 
wrong with 16275 post id 436333705/27/17 
"""

Nyahua

SQL to MongoDB Mapping Chart

SQL to MongoDB Mapping Chart¶

In addition to the charts that follow, you might want to consider the Frequently Asked Questions section for a selection of common questions about MongoDB.

Executables¶

The following table presents the MySQL/Oracle executables and the corresponding MongoDB executables.

Nyahua

SQL to MongoDB Mapping Chart

SQL to MongoDB Mapping Chart¶

In addition to the charts that follow, you might want to consider the Frequently Asked Questions section for a selection of common questions about MongoDB.

Executables¶

The following table presents the MySQL/Oracle executables and the corresponding MongoDB executables.

Nyahua

import pymongo, json

def db_connection(db_name, collection_name):
 client = pymongo.MongoClient('mongodb://localhost:27017/')

Nyahua

mongodump --db=<old_db_name> --collection=<collection_name> --out=data_directory/
tar -zcvf archive.tar.gz data_directory/ 

mongorestore --db=<new_db_name> --collection=<collection_name> data/<db_name>/<collection_name>.bson

Nyahua

using the csv module from the standard library and the open method to avoid leaving the file open.

The key point is using 'a' for appending when you open the file.

import csv   
fields=['first','second','third']
with open(r'name', 'a') as f:
    writer = csv.writer(f)
    writer.writerow(fields)