CodeBlogMoney

Make Money using Coding and Blogging

Python

Python String Concatenation and String Formatting

by

Python String Concatenation is the process for joining small string to make the bigger. For example, you can create a full name by joining two string-like Firstname and Lastname. Formatting will help to display variable in or end of the string.

Python String Concatenation

Python provides the easy way to concatenate Strings by using + (plus)  and * (star) Sign. There are other methods such as append(), join() and format().

Using + 

+ will adds values on either side of the operator

Here is an example :

>>> str1 = "Jhon"
>>> str2 = "Doe"
>>> print str1 + " " + str2
Jhon Doe

Using *

*  Creates new strings, concatenating multiple copies of the same string.

Here is an example :

>>> "John" * 3
'JohnJohnJohn'

String Formatting in Python

You might have the experience to use C language to print String and Integer using %s and %d. Python has similar string formatting to create new, formatted strings. The % operator is used to format variables.

Here are the examples:

>>> name = "John Doe"
>>> print "Hello, %s How are you?" % name
Hello, John Doe How are you?
>>>

String formatting using two and more than values using the tuple. A tuple is a sequence of immutable Python objects. Tuples use parentheses.

>>> name = "John Doe"
>>> salary = 10000
>>> period = "Month"
>>> print "%s earns %d per month." % (name, salary)
John Doe earns 10000 per month.
>>> print "%s earns %d per %s." % (name, salary, period)
John Doe earns 10000 per Month.

Python is supporting other function like append and join to manipulate String data.

Related Python Articles:

Read JSON File using Python Code and Prompt

JSON Pretty Print using Python- with Examples

Check out this Python code Formatter

Python Interpreter : The Best Language Interpreter

by

Python is one of the best-interpreted languages and developed by Guido van Rossum in late 1980. Python is used as the first programming choice of Google, Ubuntu, RedHat and other IT product based companies.

The Python interpreter

The Python interpreter is a program which reads Python statements and executes them immediately. To use interpreter it requires opening the command prompt or terminal windows in your development environment and write command python, and it will show this result and start interpreter. I am using Window 10’s Ubuntu shell.

[email protected]:~# python
Python 2.7.6 (default, Jun 22 2015, 17:58:13)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>

Python interpreter executes program statements immediately. To run python statements, Python command prompt will start in interactive mode and it will be very useful to try out things.

Here are some Examples of one-line commands:

[email protected]:~# python
Python 2.7.6 (default, Jun 22 2015, 17:58:13)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> print ("Hello World")
Hello World
>>> 50 * 20
1000
>>> bin(5)
'0b101'
>>>

In above examples, one will print Hello World, other will do multiplication and the third one calculates Decimal to Binary using bin().

The >>> prompt is used to enter one-line commands or code blocks that define classes or functions. Simple one-line commands are there in above example. In next example please find multi-line code blocks.

Here are some Examples of multi-line code block:

[email protected]:~# python
Python 2.7.6 (default, Jun 22 2015, 17:58:13)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> str1 = "Hello"
>>> str2 = "Hello"
>>> str1 == str2
True

In above example, it will compare two strings.

help() function is another awesome way to get help on python keywords, functions, etc.

Here is the example of checking syntax and guide of bin command. Press q to return to python interactive interpreter.

[email protected]:~# python
Python 2.7.6 (default, Jun 22 2015, 17:58:13)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> help(bin)

Help on built-in function bin in module __builtin__:

bin(...)
    bin(number) -> string

    Return the binary representation of an integer or long integer.
(END)

I love the way Python Interactive Interpreter works. How about you?

Related Python Articles:

Read JSON File using Python Code and Prompt

JSON Pretty Print using Python- with Examples

10 Python Tips and Tricks for Beginner and 9th is interesting

by

Today Python is one of the most popular languages for coding in Unix/Linux world. You can find it everywhere from Web development to Server Component development, XML parsing to configuration management. Here I will be mentioning 10 Python tips and tricks for developers.

Python is pre-installed in many Operating Systems which released in last two year. Ubuntu, Redhat, Mac OS, Free BSD , Solaris, etc.

To check which version of python is installed go to shell and type:

$ python

This command will give you the version information of Python and start Python’s interactive interpreter.

Here are the few famous applications which are built using Python such as :

  • Youtube
  • OpenStak
  • Dropbox
  • Instagram

Here are 10 Python tips and tricks for Beginners and Experts.

1. Use Python Development Environment

By using Development Environment or IDE it will increase your productivity and easy to resolve error and warning. It will also help to debug the code, easy to navigate , integrate source control such as SVN, Git.

These are the recommended IDEs for Python Development.

  • PyDev – It’s free and Open Source Eclipse-based IDE . http://www.pydev.org/
  • IDLE: The Python built-in IDE, with auto-completion, helps to Format, Run, and Debug python code.
  • Other commercial versions are PyCharm(has Community version), WingIDE.

2. Calculate days between Today and Date.

import datetime

today = datetime.date.today()

someday = datetime.date(2017, 1, 1)

diff = someday - today

print (str(diff.days) +" days")

datetime module is used to find the days between two dates. this example will find the days between today and 1 Jan 2017.

3. Command line arguments while running Python Scripts

#file name is commandlinetest.py
import sys

print 'No of arguments passed:', len(sys.argv)
print 'List of arguments :', str(sys.argv)

run this script:

$ python commandlinetest.py 10 20 30

Output
No of arguments passed: 3
List of argumenrs : ['commandlinetest.py', '10', '20', '30']

sys module will have the information about arguments passed by accessing sys.argv variable. sys.argv is a list of strings representing the arguments on the command-line.

4. String Searching made easy

The first Method will check if a string contains another string by using the in syntax. in takes two arguments, first on the left and second on the right, and returns True if the left argument is contained within the right argument.

s = "This is a String finding program"

# Method 1
if 'String' in s:
    print('String is found in this program')

# Method 2
if s.find('String') != -1:
    print('String is at ' , s.index('String'))

Second Method offers a Library method called find(). This method is used with String Variable and it returns the position of the index of desired string. If the string is not found then -1 is returned.

5. Generating Random Numbers

Python is having the random library for generating random numbers. By default random library uses system time to generate random numbers.

import random

print('Random number:->' , random.randrange(10));

print('Random Range Between 10 to 20:->' , random.randrange(10,20));

print('Random with Floating values:->' , random.uniform(0,10));

Output :
Random number:-> 9
Random Range Between 10 to 20:-> 13
Random with Floating values:-> 5.012076169955613

random.randrange(10) sets the limit from 0 to 10 and return numbers between 0 to 10.

random.randrange(10,20) gives random values between 10 to 20.

random.uniform gives the result with floating value.

6. Opening WebBrowser from Python Script

import webbrowser

webbrowser.open('http://codebeautify.org')

webbrowser module provides the easy way to open system’s default browser with URL mention in open method.

7. Calculate Program Execution time

import time

start_time = time.time()

add = 0
for i in range(1, 10000):
    add =add + i
print(add)

print("\n--- %s seconds ---" % (time.time() - start_time))

Many applications require a very precise time measurement. For this purpose, Python provides methods in time module. These methods will help you to measure execution time taken by the block of code.

In Linux and Unix, this command can let us know the execution of the python program.

$ time python nameofprogram.py

8. Converting the List to a String for Print

#declaring List
mylist = ['one', 'two', 'three']

print (', '.join(mylist))
print ('\n'.join(mylist))

To combine any list of strings into a single string, use the join method of a string object. First print statement will join string with ” , ” and second will add new line.

Output:
one, two, three
one
two
three

9. Strings Concatenating using ” + ” and more.

Python uses + and * from manipulating String.

Using +

$ python
>>> print "Jhon" + "Doe"
JhonDoe

Using *

$python
>>> print "Jhon" * 3
JhonJhonJho

10. Sorting Array of String

mylist = ['one', 'two', 'three', 'four', 'five']

mylist.sort()

for x in mylist:
    print (x);

Output:
five
four
one
three
two

Let me know your views and best Python tips in a comment below.

Validate JSON using Python – with Examples

by

This article is to Validate JSON using Python. Python has built-in JSON module to work with JSON data. Python is getting popular and becoming the first choice of startup development. JSON is used widely because of it easy to understand, compact and built-in support in JavaScript.

Validate JSON Using Python.

json.loads() method is used to validate JSON data.

Here is the function which will validate JSON data.

#JSON Validator function
import json

def json_validator(data):
    try:
        json.loads(data)
        return True
    except ValueError as error:
        print("invalid json: %s" % error)
        return False

json.loads()

json.loads() loads the JSON data to parse, it will return true or it will fail and raised the exception. This function will work as EAFP (Easier to ask for forgiveness than permission). EAFP is python’s ideology to handle this kind of situation.

Here is the Example of Validating JSON data using Python.

#Validating JSON using Phython Code
import json

def json_validator(data):
    try:
        json.loads(data)
        return True
    except ValueError as error:
        print("invalid json: %s" % error)
        return False

""" 
#Valid JSON Data

{
  "actors": {
    "actor": [
      {
        "id": "1",
        "firstName": "Tom",
        "lastName": "Cruise"
      }
    ]
  }
}

#Invalid JSON Data

 {
    {
    "actor": [
      {
        "id": "1",
        "firstName": "Tom",
        "lastName": "Cruise"
      }
    ]
  }
}
 """


print(json_validator('{"actors":{"actor":[{"id":"1","firstName":"Tom","lastName":"Cruise"}]}}' ))#prints True

print (json_validator('{{"actor":[{"id":"1","firstName":"Tom","lastName":"Cruise"}]}}')) #prints Error message and False

#End

I am using these ready-made tools to validate JSON data online.

https://codebeautify.org/jsonvalidator
https://jsonformatter.org

Are you also working with JavaScript? try this Validate JSON String Using JavaScript.