Coding for Entrepreneurs

Python Cheat Sheet

By Justin

A quick reference guide for using the Python Programming language.
Strings
Integers
## Strings ```python text = "Some string, with some stuff."
text2 = "Yet, another string here."
text3 = "Concatenation combines strings like "" + text + "" and "" + text2 + """ print(text3)


### Formatting

**`\n`: New Line**
```python
text = 'Often\nYou need a new line'
print(text)
\t: Tab
python
text = 'Often a \t tab is needed.'
print(text)
\': Escaped single quote
python
text = 'Sometimes it\'s your quote sometimes it isn\'t'
print(text)
\": Escaped double quote
python
text = "Sometimes it\'s a \"Quote from someone else\""
print(text)
\: Escaped linebreak
python
text = "Sometimes you need to have \
a inline break that isn't a linebreak."
print(text)
.lower(): Lowercase entire string
python
text = "Some string, with some stuff."
text.lower()
print(text)
"some string, with some stuff."
.upper(): Uppercase entire string
python
text = "Some string, with some stuff."
text.upper()
print(text)
"SOME STRING, WITH SOME STUFF.
.lower() and .upper() to Capitalize string
python
lower_cased = "this sentence needs to be capitalized."

cap_string = lower_cased[0].upper() + lower_cased[1:]
print(cap_string)
"This sentence needs to be capitalized."
.split() to Break up string
python
text = "Some string, with some stuff."
print(text.split())
['Some', 'string,', 'with', 'some', 'stuff.']

print(text.split(","))
['Some string', ' with some stuff.']
len() to Count String Length
python
text_length = len("Some string, with some stuff.")
print(text_length)
29

text = "Some other length"
text_length2 = len(text)
print(text_length2)
17

Substitution

Format with Keyword Arguments (Variables)
python
text = "This is {variable_a} formatted string".format(variable_a="variable based")
print(text)

text = "This is another {variable_a} formatted string with \
multiple variables like {a} {b} {c}.".format(
    variable_a="variable based", 
    a="some random", b="replacement", c="text")
print(text)

text = """So, {name}, the best part is formated strings you don't have to order it. 
And these keyword argument replacements, ({var_a}, {var_b}, {name}) can be reused over and over.
Seriously {name}, this is some fun formatting.""".format(
            name="Jerry", 
            var_a="Variable 1", 
            var_b="Variable 2")
print(text)
Format with Arguments
python
text = "This is {0} formatted string".format("argument based")
print(text)

text = "This is another {0} formatted string \
with multiple variables like {1} {2} {3}.".format(
    "variable based", 
    "some random", 
    "replacement", 
    "text"
    )
print(text)

text = """So, {0}, the best part is formated strings you don't have to order it. 
And these argument replacements, ({1}, {2}, {0}) can be reused over and over.
Seriously {0}, this is some fun formatting.""".format(
            "Jerry", 
            "Variable 1", 
            "Variable 2")
print(text)
%s Substitution
python
text = "This is %s formatted string" %("replacement")
print(text)

text = "The %%s format string is not as %s, but still very %s." %("robust", "useful")
print(text)
%f Float Substitution
python
text = "0 decimal places: %.0f" %(20)
print(text)

text = "2 decimal places: %.2f" %(20)
print(text)

text = "10 decimal places: %.10f" %(20)
print(text)

text = "400 decimal places: %.400f" %(20)
print(text)
Date Substitution Docs
python
import datetime
today = datetime.date.today()
text = '{today.month}/{today.day}/{today.year}'.format(today=today)
print(text)

text = today.strftime('%-m/%-d/%y')
print(text)

now = datetime.datetime.utcnow() #utc time
text = now.strftime('%Y-%m-%d %H:%M:%S.%f')[:-3]
print(text)

now = datetime.datetime.now() #local time
date_text = now.strftime('%Y/%m/%d %H:%M:%S.%f') #[:-3]
text = "Time is: %s" %(date_text)
print(text)

now = datetime.datetime.now()
date_text = now.strftime('%B %d, %Y %H:%M:%S.%f %p')
text = "Time is %s" %(date_text)
print(text)

now = datetime.datetime.now()
date_text = now.strftime('%x')
text = "Time is %s" %(date_text)
print(text)

Integers

Integers are literal. That means, you type a number (or integer), Python treats it as a number.
some_number = 1
print(some_number)
print(123)
This is counter to Strings, of course, because integers can be within strings:
not_a_int = "123"
is_a_int = 123

Math

Integers & math go hand in hand.
* Multiply
print(10 * 10)
/ Divide
print(300 / 10)
/ Divide (rounded down result)
print(1239 / 932)
/ Divide (precise result) Notice the float/decimal number being a part of the equation.
print(1239.0 / 932)
% Remainder (aka Modulo)
print(1239 % 932)

**
Squared
print(300 ** 2)

x ** n
To the nth power
n = 13
print(9 ** n)

x ** (1.0/n)
To the nth root
Notice the float/decimal number as part of the equation.
n = 2
print(9 ** (1.0/n))
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Python Cheat Sheet