Primitive Variables¶
Numbers¶
Integers¶
1 2 3 4 5 6 7 8 9 10 11 12 13 | # create an integer
x = 5
# convert an integer string
x = str('5')
# convert a float to an integer
## note: don't depend on this for rounding, it rounds in weird ways
x = int(5.5)
# convert a string of any number base
# for example, binary
x = int('1010101', base=2)
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Floats¶
1 2 3 4 5 6 7 8 | # create a float
x = 5.5
# convert a float string
x = float("5.5")
# convert an integer to a float
x = float(5)
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Basic math operations¶
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | x = 100
# 1. Add
x = x + 5
x += 5
# 2. Subtract
x = x - 5
x -= 5
# 3. Multiply
x = x * 5
x *= 5
# 4. Divide
x = x / 5
x /= 5
# 5. Power
x = x ** 2
x **= 2
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Advanced math operations¶
1 2 3 4 5 6 7 8 | # 1. Integer Division
x = x // 5
x //= 5
# 2. Modulo
x = 84
x = x % 5
x %= 5
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Use the math library¶
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | import math
x = 10
# pow is power, same as x ** 2
x = math.pow(x, 2)
# ceil rounds up and floor rounds down
x = 5.5
y = math.ceil(x) # y is 6.0
z = math.floor(x) # z in 5.0
# some other useful ones:
math.sqrt(x)
math.cos(x)
math.sin(x)
math.tan(x)
# this will give you pi:
math.pi
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Strings¶
Add two strings together¶
1 2 3 4 | first_name = "euclid "
space = " "
last_name = "von rabbitstein"
full_name = first_name + space + last_name
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Repeat a string¶
1 2 3 4 5 6 7 | message = "Repeat me!"
repeated10 = message * 10
# I like to use it for pretty printing code results
line = "-" * 12
print(" Title! ")
print(line)
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Index into a string¶
1 2 3 4 5 | first_name = "Euclid"
last_name = "Von Rabbitstein"
first_initial = first_name[0]
last_initial = last_name[0]
initials = first_initial + last_initial
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Slice a string¶
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | # the syntax is
# my_string[start:stop]
# this includes the start position but goes UP TO the stop
# you can leave either empty to go to the front or end
target = "door"
last_three = target[1:]
first_three = target[:3]
middle_two = target[1:3]
# you can use negatives to slice off the end!
all_but_last = target[:-1]
pig_latin = target[1:] + target[0] + "ay"
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String’s inner functions¶
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | full_name = "euclid von Rabbitstein"
# all caps
full_name_uppered = full_name.upper()
# all lower
full_name_lowered = full_name.lower()
# use lower to make sure something is lower before you compare it
user_command = "Exit"
if user_command.lower() == "exit":
print("now I can exit!")
# first letter capitalized
full_name_capitalized = full_name.capitalize()
# split into a list
full_name_list = full_name.split(" ")
# strip off any extra spaces
test_string = " extra spaces everywhere "
stripped_string = test_string.strip()
# replace things in a string
full_name_replaced = full_name.replace("von", "rabbiticus")
# use replace to delete things from a string!
test_string = "annoying \t tabs in \t the string"
fixed_string = test_string.replace("\t","")
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