Section 1
Preview this deck
string.index(x , y,z)
Front
| 5 | 0 | ||
| 4 | 0 | ||
| 3 | 0 | ||
| 2 | 0 | ||
| 1 | 0 |
Active users
0
All-time users
0
Favorites
0
Last updated
6 years ago
Date created
Mar 1, 2020
Cards (61)
Section 1
(50 cards)
string.index(x , y,z)
Returns the index of substring(x) inside a string. If not found it raises ValueError. y and z are start(inclusive) and stop(noninclusive) indexes respectively.
divmod(x,y)
returns the tuple (x//y, x%y)
list addition (+)
List concatenation
random.seed(x)
if x is not provided then it seeds based on the time Can provide an integer to assign a specific randomness
PEMDAS
Parentheses, Exponents, Multiplication, Division (modulus), Addition, Subtraction
Unpacking
a,b,c = (5,3,9) out: a = 5 b = 3 c = 9
file.read()
reads the contents of the file in its entirety
sorted(iterable[, key][, reverse])
returns the sorted iterable. Can pass a function into "key = " or make your own using the lambda function. reverse = True will go from high to low or Z to A.
del list[a:b]
deletes elements in the list from index a (inclusive) to index b (exclusive)
file.readline()
returns one line from the file.
Modulus with negative in numerator
-25% 3 = 2 Returns a positive number. Multiply the denominator by a negative number to go below the numerator then the answer is the amount you add up by to get the remainder
hex(x)
returns hexadecimal representation of an integer hex(12648430) '0xc0ffee'
math.e
the value of e
TypeError
-Raised when an operation or function is applied to an object of inappropriate type.
math.radians(x)
converts to radians from degrees input
dict.values()
Returns list of dictionary dict's values. Same as keys in that if you update after creating a values list, the list will update automatically.
Modulus with negative in denominator
5%-2 = -1 Result will be negative. Multiply by a negative number to go above the numerator then subtract to get the remainder
Valid Identifiers
Variables cannot start with numbers Variables cannot contain symbols
string.upper()
returns the uppercase version of the string
math.sin(x)
sine of x (x in radians)
dict.update(dict2)
adds dict2 key value pairs to the first dict. can be a symbol name for dict or a {} notation inside of the update()
A ValueError exception is raised
If you call the index method to locate an item in a list and the item is not found, this happens
math.pi
the value of pi
string.isalpha()
Returns true (a nonzero number) if the character is a letter. If it is not then it is a zero.
Lambda
anonymous function. general format is: lambda x: x+1 x is the input and after the colon is the output
random.random()
takes no arguments, returns floats between 0 and 1
file.readlines()
returns a list of the lines.
ZeroDivisionError
Dividing by an expression that evaluates to zero (divide by zero)
Pythonic Assignment
a,b,c = 5/4, 1 , 2 out: a= 5/4 b = 1 c = 2
random.randint(x,y)
returns a random integer between x and y (including both x and y)
SyntaxError
Errors with syntax
string.join(iterable)
takes the iterable and concatenates each element in a string with the string before join as the separator
dictionary
can be made with {} or dict() dict(x=4,y=8) are keyword arguments that can be passed through to create key-value pairs on initialization.
string.capitalize()
returns the string with only the first letter in first word capitalized. Lowercase everything else
string.lower()
returns the lowercase version of the string
XOR (^)
Takes the binary of each number then does an xor for each bit. If one is smaller than the other then it just does the smallest ones length
dict.items()
Returns a list of dict's (key, value) tuple pairs. Updates even after it is used
dict.keys()
Returns a list of keys. If a key-value pair is added after the .keys() is used, the list will still update that key into the list.
bin(x)
converts number to binary. returns string bin(2796202) '0b1010101010101010101010'
list.pop([i])
Remove the item at the given position in the list, and return it. If no index is specified, a.pop() removes and returns the last item in the list. (The square brackets around the i in the method signature denote that the parameter is optional, not that you should type square brackets at that position. You will see this notation frequently in the Python Library Reference.)
list.append(value)
appends an element to list. Modifies the original list, doesn't return anything
list.extend(list2)
Takes a iterable and appends each element to the list. Modifies the original list, doesn't return anything
list.insert(i, x)
Insert an item at a given position. The first argument is the index of the element before which to insert, so a.insert(0, x) inserts at the front of the list, and a.insert(len(a), x) is equivalent to a.append(x).
string.find(x,y,z)
Returns the position of the first occurrence of item x in the string, else returns -1. optional start(y) and stop(z) indexes
random.gauss(mu,sigma)
returns a random value on based on the mean (mu) and standard deviation (sigma)
string.title()
Returns the string with each word starting with a capital
string.strip("string")
strips "string" from original string in front and back as many times as possible. If no argument is given then it removes white space characters that are trailing or leading
with (file i/o)
Opens a file, manipulates based on what is indented, then closes the file automatically. with open('output.txt', 'w') as f: f.write('Hi there!')
pow(x,y,z)
Return x to the power y; if z is present, return x to the power y, modulo z (computed more efficiently than pow(x, y) % z).
int(x,y)
Can be a string for x, converts to base 10. y specifies the base that x is in. If y is not provided it assumes it is base 10
Section 2
(11 cards)