Difference between revisions of "PythonOnSHIPs"

Revision as of 06:42, 6 June 2013

Presents the basic concepts of programming for newbies.

An introduction to the python interpreter, variables and types of data they store. Using math functions and python as a calculator.

Exercises:

Evaluate the square root of 10.1*10.2 + 15.3*15.4
What happens when you add two string variables together?
Create a numpy integer array of values from 0 to 100, incrementing in steps of 2
Create a numpy floating-point array of 101 elements that range in value from 0.0 to 1.0
Perform the following operations (in order) on the previous array: trignometric cosine, multiply by 1000.0 and convert it to integer format.
Find the minimum and maximum value of the resulting array in previous exercise.
Find the sum total of all elements of the resulting array.
What is the length of the array 'a' created by the following numpy command: a = np.zeros( int(np.sqrt(np.pi*100)+3.) )?
What is the data type of the array 'a' in the previous exercise?
Create an array 'x' of size 20 with floating point values between 1 and 20. Create a second array 'y' of size 20 with floating point values between 1 and 20. These represent the (x,y) coordinate values of 20 objects on a Cartesian grid. Calculate the distance between a point at (2.5,7.8) and all (x,y) pair objects, and store the resulting distance values in a variable 'dist'.
Create a 2-Dimensional numpy array of size 15 columns X 17 rows filled with zeros. Set the middle column to 10. Set the last five rows to 20.

Script writing for python and If/Then/Else constructs and loops.

Exercises:

For all prime numbers up to 13, calculate and print the square of the prime number.
Define a list of 5 stars in numpy variables x, y, flux. Where, x, y are the coordinates and flux is the brightness in some units. For the star in the middle of the list (at index position 2) write a script to calculate and print the difference in position and in flux.
A star has a position as follows: ra = 15.2345 (degrees), dec = -45.23435 (degrees) in epoch J2000.0 measurements. It has a proper motion of -1.2 "/yr in right ascension and +0.35 "/yr in declination. Write a program to print the right ascension and declination of the object when WISE looks at it in April of 2009?
Write a script to calculate and print when this object cross the declination line at 0.0?

@@ Line 27: / Line 27: @@
 :'''Exercises''':
 ::* For all prime numbers up to 13, calculate and print the square of the prime number.
-::* Define a list of 5 stars in numpy variables x, y, flux.  Where, x, y are the coordinates and flux is the brightness in some units.  For the star in the middle of the list (at index position 2) calculate and print the difference in position and in flux.
+::* Define a list of 5 stars in numpy variables x, y, flux.  Where, x, y are the coordinates and flux is the brightness in some units.  For the star in the middle of the list (at index position 2) write a script to calculate and print the difference in position and in flux.
-::* A star has a position as follows: ra = 15.2345 (degrees), dec = -45.23435 (degrees) in epoch J2000.0 measurements.  It has a proper motion of -1.2 "/yr in right ascension and +0.35 "/yr in declination.  What is the right ascension and declination of the object when WISE looks at it in April of 2009?
+::* A star has a position as follows: ra = 15.2345 (degrees), dec = -45.23435 (degrees) in epoch J2000.0 measurements.  It has a proper motion of -1.2 "/yr in right ascension and +0.35 "/yr in declination.  Write a program to print the right ascension and declination of the object when WISE looks at it in April of 2009?
-::* When does this object cross the declination line at 0.0?
+::* Write a script to calculate and print when this object cross the declination line at 0.0?