Python Crash Course

Please note, this is not meant to be a comprehensive overview of Python or programming in general.

This notebook is just a code reference and no written explanations here

This notebook will just go through the basic topics in order:

Data types
- Numbers
- Strings
- Printing
- Lists
- Dictionaries
- Booleans
- Tuples
- Sets
Comparison Operators
if, elif, else Statements
for Loops
while Loops
range()
list comprehension
functions
lambda expressions
map and filter
methods

Data types

Numbers



In [6]:

    
1 + 1









    Out[6]:





2



In [7]:

    
1 * 3









    Out[7]:





3



In [8]:

    
1 / 2









    Out[8]:





0.5



In [9]:

    
2 ** 4









    Out[9]:





16



In [10]:

    
4 % 2









    Out[10]:





0



In [11]:

    
5 % 2









    Out[11]:





1



In [12]:

    
(2 + 3) * (5 + 5)









    Out[12]:





50

Variable Assignment



In [13]:

    
# Can not start with number or special characters
name_of_var = 2



In [14]:

    
x = 2
y = 3



In [15]:

    
z = x + y



In [16]:

    
z









    Out[16]:





5

Strings



In [17]:

    
'single quotes'









    Out[17]:





'single quotes'



In [18]:

    
"double quotes"









    Out[18]:





'double quotes'



In [19]:

    
" wrap lot's of other quotes"









    Out[19]:





" wrap lot's of other quotes"

Printing



In [20]:

    
x = 'hello'



In [21]:

    
x









    Out[21]:





'hello'



In [22]:

    
print(x)









    



hello



In [23]:

    
num = 12
name = 'Sam'



In [24]:

    
print('My number is: {one}, and my name is: {two}'.format(one=num,two=name))









    



My number is: 12, and my name is: Sam



In [25]:

    
print('My number is: {}, and my name is: {}'.format(num,name))









    



My number is: 12, and my name is: Sam

Lists



In [26]:

    
[1,2,3]









    Out[26]:





[1, 2, 3]



In [27]:

    
['hi',1,[1,2]]









    Out[27]:





['hi', 1, [1, 2]]



In [28]:

    
my_list = ['a','b','c']



In [29]:

    
my_list.append('d')



In [30]:

    
my_list









    Out[30]:





['a', 'b', 'c', 'd']



In [31]:

    
my_list[0]









    Out[31]:





'a'



In [32]:

    
my_list[1]









    Out[32]:





'b'



In [33]:

    
my_list[1:]









    Out[33]:





['b', 'c', 'd']



In [34]:

    
my_list[:1]









    Out[34]:





['a']



In [35]:

    
my_list[0] = 'NEW'



In [98]:

    
my_list









    Out[98]:





['NEW', 'b', 'c', 'd']



In [99]:

    
nest = [1,2,3,[4,5,['target']]]



In [100]:

    
nest[3]









    Out[100]:





[4, 5, ['target']]



In [101]:

    
nest[3][2]









    Out[101]:





['target']



In [102]:

    
nest[3][2][0]









    Out[102]:





'target'

Dictionaries



In [37]:

    
d = {'key1':'item1','key2':'item2'}



In [38]:

    
d









    Out[38]:





{'key1': 'item1', 'key2': 'item2'}



In [39]:

    
d['key1']









    Out[39]:





'item1'

Booleans



In [40]:

    
True









    Out[40]:





True



In [41]:

    
False









    Out[41]:





False

Tuples



In [42]:

    
t = (1,2,3)



In [43]:

    
t[0]









    Out[43]:





1



In [44]:

    
t[0] = 'NEW'









    



---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-44-97e4e33b36c2> in <module>()
----> 1 t[0] = 'NEW'

TypeError: 'tuple' object does not support item assignment

Sets



In [45]:

    
{1,2,3}









    Out[45]:





{1, 2, 3}



In [46]:

    
{1,2,3,1,2,1,2,3,3,3,3,2,2,2,1,1,2}









    Out[46]:





{1, 2, 3}

Comparison Operators



In [47]:

    
1 > 2









    Out[47]:





False



In [48]:

    
1 < 2









    Out[48]:





True



In [49]:

    
1 >= 1









    Out[49]:





True



In [50]:

    
1 <= 4









    Out[50]:





True



In [51]:

    
1 == 1









    Out[51]:





True



In [52]:

    
'hi' == 'bye'









    Out[52]:





False

Logic Operators



In [53]:

    
(1 > 2) and (2 < 3)









    Out[53]:





False



In [54]:

    
(1 > 2) or (2 < 3)









    Out[54]:





True



In [55]:

    
(1 == 2) or (2 == 3) or (4 == 4)









    Out[55]:





True

if,elif, else Statements



In [56]:

    
if 1 < 2:
    print('Yep!')









    



Yep!



In [57]:

    
if 1 < 2:
    print('yep!')









    



yep!



In [58]:

    
if 1 < 2:
    print('first')
else:
    print('last')









    



first



In [59]:

    
if 1 > 2:
    print('first')
else:
    print('last')









    



last



In [60]:

    
if 1 == 2:
    print('first')
elif 3 == 3:
    print('middle')
else:
    print('Last')









    



middle

for Loops



In [61]:

    
seq = [1,2,3,4,5]



In [62]:

    
for item in seq:
    print(item)



In [63]:

    
for item in seq:
    print('Yep')









    



Yep
Yep
Yep
Yep
Yep



In [64]:

    
for jelly in seq:
    print(jelly+jelly)

while Loops



In [65]:

    
i = 1
while i < 5:
    print('i is: {}'.format(i))
    i = i+1









    



i is: 1
i is: 2
i is: 3
i is: 4

range()



In [66]:

    
range(5)









    Out[66]:





range(0, 5)



In [67]:

    
for i in range(5):
    print(i)



In [68]:

    
list(range(5))









    Out[68]:





[0, 1, 2, 3, 4]

list comprehension



In [69]:

    
x = [1,2,3,4]



In [70]:

    
out = []
for item in x:
    out.append(item**2)
print(out)









    



[1, 4, 9, 16]



In [71]:

    
[item**2 for item in x]









    Out[71]:





[1, 4, 9, 16]

functions



In [72]:

    
def my_func(param1='default'):
    """
    Docstring goes here.
    """
    print(param1)



In [73]:

    
my_func









    Out[73]:





<function __main__.my_func>



In [74]:

    
my_func()









    



default



In [75]:

    
my_func('new param')









    



new param



In [76]:

    
my_func(param1='new param')









    



new param



In [77]:

    
def square(x):
    return x**2



In [78]:

    
out = square(2)



In [79]:

    
print(out)

lambda expressions



In [80]:

    
def times2(var):
    return var*2



In [81]:

    
times2(2)









    Out[81]:





4



In [82]:

    
lambda var: var*2









    Out[82]:





<function __main__.<lambda>>

map and filter



In [83]:

    
seq = [1,2,3,4,5]



In [84]:

    
map(times2,seq)









    Out[84]:





<map at 0x105316748>



In [85]:

    
list(map(times2,seq))









    Out[85]:





[2, 4, 6, 8, 10]



In [86]:

    
list(map(lambda var: var*2,seq))









    Out[86]:





[2, 4, 6, 8, 10]



In [87]:

    
filter(lambda item: item%2 == 0,seq)









    Out[87]:





<filter at 0x105316ac8>



In [88]:

    
list(filter(lambda item: item%2 == 0,seq))









    Out[88]:





[2, 4]

methods



In [111]:

    
st = 'hello my name is Sam'



In [112]:

    
st.lower()









    Out[112]:





'hello my name is sam'



In [113]:

    
st.upper()









    Out[113]:





'HELLO MY NAME IS SAM'



In [103]:

    
st.split()









    Out[103]:





['hello', 'my', 'name', 'is', 'Sam']



In [104]:

    
tweet = 'Go Sports! #Sports'



In [106]:

    
tweet.split('#')









    Out[106]:





['Go Sports! ', 'Sports']



In [107]:

    
tweet.split('#')[1]









    Out[107]:





'Sports'



In [92]:

    
d









    Out[92]:





{'key1': 'item1', 'key2': 'item2'}



In [93]:

    
d.keys()









    Out[93]:





dict_keys(['key2', 'key1'])



In [94]:

    
d.items()









    Out[94]:





dict_items([('key2', 'item2'), ('key1', 'item1')])



In [95]:

    
lst = [1,2,3]



In [96]:

    
lst.pop()









    Out[96]:





3



In [108]:

    
lst









    Out[108]:





[1, 2]



In [109]:

    
'x' in [1,2,3]









    Out[109]:





False



In [110]:

    
'x' in ['x','y','z']









    Out[110]:





True