Python Programming I
INFO 253B: Backend Web Architecture
Kay Ashaolu
Let's talk about programming
- At the end of the day, we have to tell these computers what to do
- Well, until they tell themselves what to do
- That's when we have bigger problems than we do now
But on a serious note
- In order to build back end web systems, we'll need to learn a programming language
- A programming language enables us to tell servers/computers/boxes what to do when desktops/other servers/mobile phones/refrigerators ask a question
What is a programming language?
A programming language is a formal language, which comprises a set of instructions used to produce various kinds of output. Programming languages are used in computer programming to create programs that implement specific algorithms.
There's a few general types of programming languages
- Compiled Languages: Languages that goes through a special program called a compiler that creates lower level code that computers directly understand
- Interpreted Languages: Languages that are directly executed by an interpreter as the code is read line by line
Python! A interpreted Language
- We will use Python in this class
- Python is an interpreted language
- In general, interpreted languages are easier to get started
Let's learn some Python
def hello_world():
print("Hello World!")
if __name__ == "__main__":
hello_world()Variables and Types
def integers_demo():
testInt = 5
testFloat = 2.9
return testInt * testFloat
def string_demo():
testString = "hello "
testNumTimes = 3
return testString * testNumTimes
if __name__ == "__main__":
print(integers_demo())
print(string_demo())Basic String Operations
def string_demo_length():
myString = "This is a new string"
return len(myString)
def string_demo_substring():
myString = "This is a new string"
return myString[3:7]
def string_demo_reverse():
myString = "This is a new string"
return myString[::-1]
if __name__ == "__main__":
print(string_demo_length())
print(string_demo_substring())
print(string_demo_reverse())
String Formatting
def string_demo_formatting():
numTimes = 3
temperature = 50.7
message = "she sells seashells by the seashore"
return f"I would like to write {message} {numTimes} times. By the way the temperature outside is {temperature} degrees outside."
if __name__ == "__main__":
print(string_demo_formatting())
Lists
def testLists():
mylist = []
mylist.append(1)
mylist.append(2)
mylist.append(3)
print(mylist[0]) # prints 1
print(mylist[1]) # prints 2
print(mylist[2]) # prints 3
for x in mylist:
print(x)
if __name__ == "__main__":
testLists()
Dictionaries
def testDictionaries():
phonebook = {
"John" : 938477566,
"Jack" : 938377264,
"Jill" : 947662781
}
del phonebook["John"]
return phonebook
if __name__ == "__main__":
print(testDictionaries())
Questions?
Python Programming I - Backend Webarch
By kayashaolu
Python Programming I - Backend Webarch
Course Website: https://www.ischool.berkeley.edu/courses/info/253b
- 743
