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Python Cheatsheet

Contents

Who is this for?¶

This crash-course makes the assumption that you already have some programming experience, but perhaps none with Python.

In [1]:
`# You can write a comment using an octothorpe or 'hash' symbol`

Printing to terminal¶

In [2]:
`print("Hello World!")`
`Hello World!`

Variables and assignment¶

In [3]:
```my_number = 5
my_float = 0.2
my_string = "Hello"
also_my_string = 'Hello'```
In [4]:
```print("{} is of {}".format(my_number, type(my_number)))
print("{} is of {}".format(my_float, type(my_float)))
print("{} is of {}".format(my_string, type(my_string)))
print("{} is of {}".format(also_my_string, type(also_my_string)))```
```5 is of <class 'int'>
0.2 is of <class 'float'>
Hello is of <class 'str'>
Hello is of <class 'str'>```

Terminal input¶

In [5]:
```my_result = input('please enter a word: ')
print("result: {}".format(my_result))```
```please enter a word: Hello
result: Hello```

Mathematical operations¶

In [6]:
```my_result = 5 + 2 # add
print("result: {}".format(my_result))```
`result: 7`
In [7]:
```my_result = 5 - 2 # substract
print("result: {}".format(my_result))```
`result: 3`
In [8]:
```my_result = 5 * 2 # multiply
print("result: {}".format(my_result))```
`result: 10`
In [9]:
```my_result = 5 / 2 # divide
print("result: {}".format(my_result))```
`result: 2.5`
In [10]:
```my_result = 5 % 2 # modulo
print("result: {}".format(my_result))```
`result: 1`
In [11]:
```my_result = 5 ** 5 # exponent
print("result: {}".format(my_result))```
`result: 3125`

Boolean operations¶

In [12]:
```my_result = True
print("result: {}".format(my_result))

my_result = False
print("result: {}".format(my_result))```
```result: True
result: False```
In [13]:
```# and
my_result = False and False
print("result: {}".format(my_result))

my_result = False and True
print("result: {}".format(my_result))

my_result = True and False
print("result: {}".format(my_result))

my_result = True and True
print("result: {}".format(my_result))```
```result: False
result: False
result: False
result: True```
In [14]:
```# or
my_result = False or False
print("result: {}".format(my_result))

my_result = False or True
print("result: {}".format(my_result))

my_result = True or False
print("result: {}".format(my_result))

my_result = True or True
print("result: {}".format(my_result))```
```result: False
result: True
result: True
result: True```
In [15]:
```# not
my_result = not True
print("result: {}".format(my_result))

my_result = not False
print("result: {}".format(my_result))```
```result: False
result: True```

Relational operations¶

In [16]:
```my_result = 5 > 2 # greater than
print("result: {}".format(my_result))

my_result = 5 >= 2 # greater than or equal to
print("result: {}".format(my_result))

my_result = 5 < 2 # less than
print("result: {}".format(my_result))

my_result = 5 <= 2 # less than or equal to
print("result: {}".format(my_result))

my_result = 5 == 2 # equal to
print("result: {}".format(my_result))```
```result: True
result: True
result: False
result: False
result: False```

Conditional statements¶

In [17]:
```age = 17
uk_drinking_age = 18

if(age >= uk_drinking_age): # IF
print("you can drinking!")
elif(age == 17):            # ELSE IF
print("you can drink on your birthday!")
else:                       # ELSE
print("you can't drink!")```
`you can drink on your birthday!`

Data structures¶

In [18]:
```# LIST
shopping_list = ["Carrots", "Onions", "Chicken", "Coconuts"]
print(shopping_list)
print(shopping_list [0]) # Python is zero-indexed

shopping_list.append("Ice cream")
print(shopping_list)```
```['Carrots', 'Onions', 'Chicken', 'Coconuts']
Carrots
['Carrots', 'Onions', 'Chicken', 'Coconuts', 'Ice cream']```
In [19]:
```# DICTIONARY
shopping_list = {"Carrots": 5, "Onions": 2, "Chicken": 1, "Coconuts": 1}
print(shopping_list)
print("Careful - dictionaries are not ordered in older versions of Python.")
print(shopping_list['Carrots'])```
```{'Carrots': 5, 'Onions': 2, 'Chicken': 1, 'Coconuts': 1}
Careful - dictionaries are not ordered in older versions of Python.
5```
In [20]:
```# TUPLE
my_result = (5, 6)
print(my_result)

my_result = (5, "hello", 5.5, True, 2)
print(my_result)```
```(5, 6)
(5, 'hello', 5.5, True, 2)```

Loops¶

In [21]:
```# FOR

shopping_list = ["Carrots", "Onions", "Chicken", "Coconuts"]

for item in shopping_list:
print(item)```
```Carrots
Onions
Chicken
Coconuts```
In [22]:
```# FOR

for index in range(0,10):
print(index)```
```0
1
2
3
4
5
6
7
8
9```
In [23]:
```# WHILE
number = 0

while(number < 18):
print(number)
number += 1

print("number was no longer below 18!")```
```0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
number was no longer below 18!```

Functions¶

In [24]:
```def my_function(): # create a function
print("No parameters passed in")

my_function()      # call a function```
`No parameters passed in`
In [25]:
```def another_function(name):
print("Parameter passed in: {}".format(name))

another_function("Derek")```
`Parameter passed in: Derek`
In [26]:
```def greater_than(left_operand, right_operand):
my_result = left_operand > right_operand
return my_result      # returning a value from the function

print(greater_than(5, 2)) # printing the value returned from the function```
`True`

Packages¶

In [27]:
```import datetime

print(datetime.datetime.now())```
`2019-07-12 19:37:47.117505`

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