University:
Boston University
Course:
CAS CS 501 | Computer Science Practicum
Academic year:

2021
Views:

367

Pages:

30
Author:

Nikolas Trujillo

Python for Non-programmers A Gentle Introduction 1 Introduction This Tutorial This is for non-programmers. The first half is very gentle. The second half is more in depth. Introduction This Tutorial This is for non-programmers. The first half is very gentle. The second half is more in depth. If you have any programming experience, feel free to entertain yourself at codingbat.com/python Introduction This Tutorial This is for non-programmers. The first half is very gentle. The second half is more in depth. If you have any programming experience, feel free to entertain yourself at codingbat.com/python Get ready to type... this is definitely interactive. Introduction Python Overview Python is named after the BBC show ”Monty Python’s Flying Circus” Introduction Python Overview Python is named after the BBC show ”Monty Python’s Flying Circus” We will focus on Python 2 today. Introduction Python Overview Python is named after the BBC show ”Monty Python’s Flying Circus” We will focus on Python 2 today. How to get Python on Katana and on Windows or Mac Introduction Python Overview Python is named after the BBC show ”Monty Python’s Flying Circus” We will focus on Python 2 today. How to get Python on Katana and on Windows or Mac Introduction Python is Interpreted Python can be run interactively. Introduction Python is Interpreted Python can be run interactively. Code ⇒ execution is almost instant; No explicit compilation step required. This allows for a faster development process Introduction Python is Interpreted Python can be run interactively. Code ⇒ execution is almost instant; No explicit compilation step required. This allows for a faster development process The final product is usually more resource intensive, and as a side effect slower then comparable C/Fortran code. Introduction Python is Interactive Practice running python, type python in the terminal, hit Enter: 1 2 3 4 % python Python 2.7 ( # 1 , Feb 28 2010 , 00:02:06) Type " help " , " copyright " , " credits " or " license " for more information . >>> The >>> is a prompt asking for the next python line of code. Sometimes you’ll see ... as a prompt too. To exit, type exit() and Enter Try it! Python as a Calculator Numbers 1 Start python (type python, then Enter), and try typing the following Addition: 1 2 + 2 2 1.5 + 2.25 Subtraction: 1 4 - 2 2 100 - .5 3 0 - 2 Multiplication: 1 2 * 3 Python as a Calculator Numbers 1 - Output 1 2 3 4 5 6 7 8 9 10 11 12 >>> 2 + 4 >>> 1.5 3.75 >>> 4 2 >>> 100 99.5 >>> 0 -2 >>> 2 * 6 2 + 2.25 2 - .5 2 3 Python as a Calculator Numbers 2 Division: 1 2 3 4 5 6 4 / 2 1 / 2 1.0 / 2 3/4 + 1/4 3.0/4 + 1.0/4 3.0/4.0 + 1.0/4.0 Python as a Calculator Numbers 2 - Output 1 2 3 4 5 6 7 8 9 10 11 12 >>> 2 >>> 0 >>> 0.5 >>> 0 >>> 1.0 >>> 1.0 4/2 1/2 1.0/2 3/4 + 1/4 3.0/4 + 1.0/4 3.0/4.0 + 1.0/4.0 Python as a Calculator type() type() is a function that tells you what data type Python thinks something is. Try: 1 type (1) 2 type (1.0) Python as a Calculator type() type() is a function that tells you what data type Python thinks something is. Try: 1 type (1) 2 type (1.0) results in: 1 2 3 4 >>> type (1) < type ’ int ’ > >>> type (1.0) < type ’ float ’ > Python as a Calculator type() type() is a function that tells you what data type Python thinks something is. Try: 1 type (1) 2 type (1.0) results in: 1 2 3 4 >>> type (1) < type ’ int ’ > >>> type (1.0) < type ’ float ’ > type() is a function, it takes one argument and it returns info about the argument’s type. We will talk more about functions in a bit, and create our own. Python as a Calculator Tip Press the up arrow a few times in the terminal. The Python Interpreter saves a history of what you type. Pressing up allows you to access previous lines. Hit return and you re-run a command. Python as a Calculator Variables 1 Python variables can be made of any data type. Giving a name to some value is called assignment. Variable names cannot have spaces, and they need to start with a letter. Try typing: 1 2 3 4 5 type (4) x = 4 x type ( x ) 2 * x Python as a Calculator Variables 1 - output and we get: 1 2 3 4 5 6 7 8 9 >>> type (4) < type ’ int ’ > >>> x = 4 >>> x 4 >>> type ( x ) < type ’ int ’ > >>> 2 * x 8 Python as a Calculator Note on Output Just typing a value and the interpreter spits it back out at you. If you assign 4 to a variable, nothing is printed. 1 >>> 4 2 4 3 >>> x = 4 Python as a Calculator Variables 2 Reassignment is possible: 1 2 3 4 5 6 >>> >>> 4 >>> >>> 5 x = 4 x x = 5 x Python as a Calculator Variables 2 Reassignment is possible: 1 2 3 4 5 6 >>> >>> 4 >>> >>> 5 x = 4 x x = 5 x And order of operations is as you might expect: 1 2 3 4 5 6 >>> >>> >>> 2 >>> 2 x = 3 y = 4 2 * x - 1 * y (2* x ) - (1* y ) Python as a Calculator Strings 1 Strings are surrounded by quotes: 1 " Hello " 2 " Python , I ’m your #1 fan ! " And you can still use type() to check things out: 1 type ( " Hello " ) 2 type (1) 3 type ( " 1 " ) Python as a Calculator Strings 1 - Output 1 2 3 4 5 6 7 8 9 10 >>> " Hello " ’ Hello ’ >>> " Python , I ’m your #1 fan ! " " Python , I ’m your #1 fan ! " >>> type ( " Hello " ) < type ’ str ’ > >>> type (1) < type ’ int ’ > >>> type ( " 1 " ) < type ’ str ’ > Python as a Calculator Strings 2 Strings can be combined (concatenated): 1 " Hello " + " World " Python as a Calculator Strings 2 Strings can be combined (concatenated): 1 " Hello " + " World " And you can formally print strings with the print command: 1 print " Hello " + " World " Python as a Calculator Strings 2 - Output 1 2 3 4 >>> " Hello " + " World " ’ HelloWorld ’ >>> print " Hello " + " World " HelloWorld The effect is the same, but there’s a subtle difference of missing quotes. print will become important soon, when we start writing scripts...

Python for Non-programmers - A Gentle Introduction

Related Documents

Recommended Documents

Description

Related Documents

Free up your schedule!

Take 5 seconds to unlock