Python - How to get the NSE daily data feed?

These are days when trading decisions are taken more by a software, and people write algorithms to get their trades executed. For all this to happen, you need to have the stock data feed with you. Data is nothing but the daily open,close,high, low and volume for the stocks. Once you have the feed, the kind of things you can do with that data is endless.  In this article, we will see how to download the data feed through a Python program.

Pre-requisites:
1. Install pandas if not present already:

pip install pandas

2. Alpha Vantage has exposed free API's for downloading data feed. Install the alpha vantage package:

pip install alpha-vantage

3. You need to register yourself in Alpha vantage and get an API key.

Python - Get nth prime number

 Let us try to solve the 7th problem in Euler's project which is to get the 10,001st prime number. We will start with writing a function to check if a number is prime or not.

from math import sqrt

def isPrime(x):
    if x < 2:
        return False
    if x == 2 or x == 3:
        return True
    for i in range(2, int(sqrt(x)) + 1):
        if x % i == 0:
            return False

    return True

Perl - Connect to Oracle database and SELECT

How to connect to a database from a Perl program? Let us see in this article how to connect to Oracle and read from a table.  As a pre-requisite, we need to have the DBI and DBD::Oracle packages installed.
   In this article, we are going to see how to read name of a student from the students table.

Example 1:

#!/usr/bin/perl 
use warnings ;
use strict ;
use DBI;

$\="\n";

print "Connecting to DB..";

my $dbh = DBI->connect('dbi:Oracle:xe',  'scott', 'tiger') or
          die "Cannot connect to DB => " . DBI->errstr;
my $sth = $dbh->prepare("select first_name, last_name from students where id = 10000") or
          die "Couldn't prepare statement: " . $dbh->errstr;
$sth->execute();

while (my ($f_name, $l_name) = $sth->fetchrow_array()){
    printf "First Name : %-10s Last Name : %-20s\n" , $f_name,  $l_name;
}
#$sth->finish();
$dbh->disconnect();

The above program when run will print the First Name and last name of the student whose id is 10000.

grep vs awk - Part 2

In this article, we will see more awk alternatives for the frequently used grep commands. This is in continuation to the grep vs awk - Part 1. Let us consider a sample file as shown below:

$ cat file
Unix

Linux
Uniix
Solaris
AIX
ArchLinux
Ubuntu

1. Search for a pattern present in a variable

$ x="Linux"
$ grep "$x" file
Linux

The variable x contains the search pattern. Using grep, the variable can directly be used.

$ awk -v var="$x" '$0 ~ var' file
Linux

In awk, the variable cannot be used directly. It needs to be passed to awk from shell using the -v option. More about the variable passing to awk.

How to use arrays in ksh?

  Array, as in any programming language, is a collection of elements. These elements need not be of the same type. One important difference here is shells support only one-dimensional arrays.

1. Creating an array:
   Creating an array is pretty simple.

$ typeset -a arr
$ arr[0]=25
$ arr[1]=18
$ arr[2]="hello"

 Using the typeset command, we let the shell know that we are intending to use the variable arr to store a list of elements. The -a indicates arr as an indexed array. Then the elements are assigned one by one using their index positions. Array indexing always starts from 0.