Python 3 Beginner's Reference Cheat Sheet
Special
characters
# coment
\n new line
\<char> scape char
Numeric
operators
+ addition
- subtraction
* multiplication
/ division
** exponent
% modulus
// floor division
Boolean
operators
== equal
!= different
> higher
< lower
>= higher or equal
<= lower or equal String methods
string.upper() converts to uppercase
string.lower() converts to lowercase
string.count(x) counts how many
times x appears
string.find(x) position of the x first
occurrence
string.replace(x,y)
replaces x for y
string.strip(x) returns a list of values
delimited by x
string.join(L) returns a string with L
values joined by string
string.format(x) returns a string that
includes formatted x
List methods
list.append(x) adds x to the end of the list
list.extend(L) appends L to the end of the list
list.insert(i,x) inserts x at i position
list.remove(x) removes the first list item whose
value is x
list.pop(i) removes the item at position i and
returns its value
list.clear() removes all items from the list
list.index(x) returns a list of values delimited
by x
list.count(x) returns a string with list values
joined by S
list.sort() sorts list items
list.reverse() reverses list elements
list.copy() returns a copy of the list
Dictionary methods
dict.keys() returns a list of keys
dict.values() returns a list of values
dict.items() returns a list of pairs (key,value)
dict.get(k) returns the value associtated to
the key k
dict.pop() removes the item associated to
the key and returns its value
dict.update(D) adds keys-values (D) to dictionary
dict.clear() removes all keys-values from the
dictionary
dict.copy() returns a copy of the dictionary
Main data types
boolean = True / False
integer = 10
float = 10.01
string = “123abc”
list = [ value1, value2, … ]
dictionary = { key1:value1, key2:value2, …}
String operations
string[i] retrieves character at position i
string[-1] retrieves last character
string[i:j] retrieves characters in range i to j
dict = {} defines an empty dictionary
dict[k] = x stores x associated to key k
dict[k] retrieves the item with key k
del dict[k] removes the item with key k
List operations
list = [] defines an empty list
list[i] = x stores x with index i
list[i] retrieves the item with index I
list[-1] retrieves last item
list[i:j] retrieves items in the range i to j
del list[i] removes the item with index i
Dictionary operations
and logical AND
or logical OR
not logical NOT
Comparison
operators
Alvaro Sebastian
http://www.sixthresearcher.com
Legend: x,y stand for any kind of data values, s for a string, n for a number, L for a list where i,j are list indexes, D stands for a dictionary and k is a dictionary key.
