Naming
The name of variables in Python can consist of lowercase letters (a to z), uppercase letters (A to Z), numbers (0 to 9), or the underscore character (_). Spaces aren't be allowed in a variable name.
Additionally, a variable name must not start with a digit, and it is not recommended to start it with the underscore character except in very specific cases, for example, if __name__ == "__main__"
Furthermore, it is essential to avoid using a built-in word in Python as a variable name (for example: print, range, for, from, etc.). |
Type of variables
Integer |
|
Float |
|
String " " or ' ' or ''' ''' |
|
List [ ..., ...] |
|
Dictionary {key : value, ...} |
{key:value}
dict[key] = value
|
Tuple (..., ...) |
|
Set {..., ...} |
|
Boolean True&False |
Frozenset frozenset({..., ...}) |
|
- To check the type of variable, type(variable)
- Floats can be in scientific format, like 3e8 = 3*10^8.
- To convert float to scientific format, "%e"%float
. It will return a string
- To use mathematical constant e, it should import module math. math.e
- To make a long number visible, using underscores "_" to separate digits in the version 3.6+, like 380_000
Conversion
FLoat & Int |
|
List to Str |
'separator'.join(list)
|
Str to List |
list(string)
string.split('separator')
|
- int(float)
returns only the integer part of the float and round(float, num)
is used to round a number to a specified number of decimal places.
- 'sep'.join()
cannot combine lists with full integers. [str(i) for i in list; separator by default is space
|
|
Properties & Common Functions
NUM |
int()
round(value, decimal)
abs()
|
STRING |
iterable, indexable, immutable; len(); str + str, str * positive int; str.replace(a,b)
str.count(a)
str.title()
str.upper()
str.lower()
str.strip()
str.rstrip()
str.lstrip()
|
LIST |
list[start:stop:step]
enumerate(list)
max()
min()
sum()
list.reverse()
reversed(list)
list * int, list + list; [i for i in list for _ in range()]
list.append()
list.insert(item,pos)
list.remove()
list.pop()
del list[]
list.index(item)
sorted(list)
list.sort()
|
RANGE |
range(start, stop, step)
step could be negative; similar to lists, but immutable |
DICT |
iterable by key, ordered by key or value : sorted(dic)
sorted(dic, key=dico.get)
dic.items()
dic.keys()
dic.values()
dic[key]
or dic.get(key)
dic[key]=value
del dic[key]
dict.pop(key)
; len() |
TUPLE |
len(), iterable, ordered, indexiable, immutable. Avoid containing mutable variables |
SET |
iterable, mutable, unordered, indexable; set.add()
set.remove()
set.updata()
set(list1) & set(list2)
sames; set(list1) | set(list2)
union; set(list1) - set(list2)
|
FROZENSET |
f1.union(f2)
f1.intersection(f2)
|
- If strings or lists are multiplied by a negative integer or a float, it will returns nothing but a null string/list or an error
- To duplicate a list, list.copy()
or list[:]
. It should exactly avoid using lst2 = lst1
, this creates a reference to the original list with the same ID id()
- list[1:n]
stop at n-1, even if negative index
- set()
can use to remove duplicated elements in lists and to take keys of a dictionary
- sets cannot be applied operators like + or *
Arithmetic Operators
x + y |
add |
x - y |
substract |
x * y |
multiply |
x ** y |
x^y |
x / y |
divide |
x // y |
integet division |
x % y |
modulus |
Assignment shortcuts: x op= y, for example, x += y is egal to x = x+y
Comparison Operators
x == y |
x != y |
x < y |
x > y |
x <= y |
x >= y |
|
Created By
Metadata
Comments
No comments yet. Add yours below!
Add a Comment
Related Cheat Sheets
More Cheat Sheets by Theo666