Python Basics#

  • Python is ** dynamically typed**

    • Type given at the time of assignment

  • Python is strongly typed

    • You can’t change the type

  • You can use the variable name for a different type of object.

Variables#

a = [1]
b = a
print(b) # [1]

b.append(2)
print(a) # [1,2]

[1]
[1, 2]


test = "Hello"

print(test)

test = 123

print(test)

Hello
123

test = "3"
print(test) # 3 IT IS CLASSED AS AN INT

test2 = str("3")
print(test2) # 3 IT IS CLASSED AS A STRING

3
3

Data Structures#

nested_tuple = (1,2,3),(4,5,6)

# Cool loops
[x[1] for x in nested_tuple]

[2, 5]

YOU CAN DO THE OBJECT ASSIGNING THINGY IN PYTHON

normal_tuple = 1,2,3
a,b,c = normal_tuple
print(a, b, c)

1 2 3

this_is_a_list = list([1,2,3,4,5])
this_is_a_list.extend([7,8,9])
this_is_a_list

[1, 2, 3, 4, 5, 7, 8, 9]

a_tuple = (1,2,3,4,5)
tuple_into_list = list(a_tuple)
tuple_into_list

[1, 2, 3, 4, 5]

string = """Like an echo in the forest

The day will come back around

As if nothing happened

Yeah, life goes on

Like an arrow in the blue sky

Another day flying by

On my pillow, on my table

Yeah, life goes on

Like this again"""

string_as_list = string.split()
string_as_list.sort(key=len)
string_as_list

['an',
 'in',
 'As',
 'if',
 'on',
 'an',
 'in',
 'by',
 'On',
 'my',
 'on',
 'my',
 'on',
 'the',
 'The',
 'day',
 'the',
 'sky',
 'day',
 'Like',
 'echo',
 'will',
 'come',
 'back',
 'life',
 'goes',
 'Like',
 'blue',
 'life',
 'goes',
 'Like',
 'this',
 'Yeah,',
 'arrow',
 'table',
 'Yeah,',
 'again',
 'forest',
 'around',
 'flying',
 'nothing',
 'Another',
 'pillow,',
 'happened']

Loops#

i = 0
while i < 10:
    print(i)
    i +=1

0
1
2
3
4
5
6
7
8
9

a_list = ['my','stomach','hurts']
for x in a_list:
    print(x)

my
stomach
hurts

for x in range(0,11):
    print(x)

0
1
2
3
4
5
6
7
8
9
10

Functions#

def a_function(text):
    print("This function takes in the parameter " + text)

a_function("meep")

This function takes in the parameter meep

Files#

f = open("testfile.txt", "r") # read
#a - append
#w - write
#x - create new data file, if exists then error
#t - text file
#b - binary data

data = f.read()
f.close()

words = data.split(" ")
words

---------------------------------------------------------------------------
FileNotFoundError                         Traceback (most recent call last)
Cell In[13], line 1
----> 1 f = open("testfile.txt", "r") # read
      2 #a - append
      3 #w - write
      4 #x - create new data file, if exists then error
      5 #t - text file
      6 #b - binary data
      8 data = f.read()

File /opt/hostedtoolcache/Python/3.8.14/x64/lib/python3.8/site-packages/IPython/core/interactiveshell.py:282, in _modified_open(file, *args, **kwargs)
    275 if file in {0, 1, 2}:
    276     raise ValueError(
    277         f"IPython won't let you open fd={file} by default "
    278         "as it is likely to crash IPython. If you know what you are doing, "
    279         "you can use builtins' open."
    280     )
--> 282 return io_open(file, *args, **kwargs)

FileNotFoundError: [Errno 2] No such file or directory: 'testfile.txt'