Python Developer

The data in the failed server won’t get removed, but there is a provision for auto-failure, which you can configure for multiple nodes. Fail-over can be triggered during any kind of socket or Memcached server level errors and not during normal client errors like adding an existing key, etc.

Flask is a web micro framework for Python based on “Werkzeug, Jinja2 and good intentions” BSD license. Werkzeug and Jinja2 are two of its dependencies. This means it will have little to no dependencies on external libraries. It makes the framework light while there is little dependency to update and less security bugs.

A session basically allows you to remember information from one request to another. In a flask, a session uses a signed cookie so the user can look at the session contents and modify. The user can modify the session if only it has the secret key Flask.secret_key.

The pass statement is a null operation. Nothing happens when it executes. You should use “pass” keyword in lowercase. If you write “Pass” you’ll face an error like “NameError: name Pass is not defined.” Python statements are case sensitive.

letter = "hai friend"

for i in letter:

if i == "a":

pass

print("pass statement is execute ..............")

else:

print(i)

☛ Lambda Vs Def.

def can hold multiple expressions while lambda is a uni-expression function.

def generates a function and designates a name so as to call it later. lambda forms a function and returns the function itself.

def can have a return statement. lambda can’t have return statements

lambda supports to get used inside a list and dictionary.

Here are a few PDB commands to start debugging Python code.

☛ Add breakpoint – <b>

☛ Resume execution – <c>

☛ Step by step debugging – <s>

☛ Move to next line – <n>

☛ List source code – <l>

☛ Print an expression – <p>

In Python, iterators are used to iterate a group of elements, containers like list.

A Python decorator is a specific change that we make in Python syntax to alter functions easily.

To make a Python Script executable on Unix, you need to do two things,

☛ Script file’s mode must be executable and

☛ the first line must begin with # ( #!/usr/local/bin/python)

Flask is a “microframework” primarily build for a small application with simpler requirements. In flask, you have to use external libraries. Flask is ready to use.

Pyramid are build for larger applications. It provides flexibility and lets the developer use the right tools for their project. The developer can choose the database, URL structure, templating style and more. Pyramid is heavy configurable.

Like Pyramid, Django can also used for larger applications. It includes an ORM.

☛ • Memcached common misuse is to use it as a data store, and not as a cache

☛ • Never use Memcached as the only source of the information you need to run your application. Data should always be available through another source as well

☛ • Memcached is just a key or value store and cannot perform query over the data or iterate over the contents to extract information

☛ • Memcached does not offer any form of security either in encryption or authentication

Flask is a web micro framework for Python based on “Werkzeug, Jinja 2 and good intentions” BSD licensed. Werkzeug and jingja are two of its dependencies.

Flask is part of the micro-framework. Which means it will have little to no dependencies on external libraries. It makes the framework light while there is little dependency to update and less security bugs.

Xrange returns the xrange object while range returns the list, and uses the same memory and no matter what the range size is.

In Python, every name introduced has a place where it lives and can be hooked for. This is known as namespace. It is like a box where a variable name is mapped to the object placed. Whenever the variable is searched out, this box will be searched, to get corresponding object.

PyChecker is a static analysis tool that detects the bugs in Python source code and warns about the style and complexity of the bug. Pylint is another tool that verifies whether the module meets the coding standard.

There are two methods which we can apply to create empty NumPy arrays.

☛ The First Method To Create An Empty Array.

import numpy

numpy.array([])

☛ The Second Method To Create An Empty Array.

# Make an empty NumPy array

numpy.empty(shape=(0,0))

There are two optional clauses you can use in the <try-except> block.

☛ The <else> clause

☛ It is useful if you want to run a piece of code when the try block doesn’t create any exception.

☛ The <finally> clause

☛ It is useful when you want to execute some steps which run, irrespective of whether there occurs an exception or not.

Python has a regular expression module <re>.

Check out the <re> expression that can check the email id for .com and .co.in subdomain.

import re

print(re.search(r"[0-9a-zA-Z.]+@[a-zA-Z]+.(com|co.in)$","jhon.sina@gmail.com"))

You need to import the os module, and then just a single line would do the rest.

import os

print (os.path.expanduser('~'))

Output:

/home/runner