[note] Basic Information

1.Keywords

Keywords

Keywords are special words that are reserved by Python and cannot be used by you to name things. They indicate commands to the Python interpreter. The following is a complete list of Python keywords:

anddelfromnotwhileaselifglobalorwithassertelseifpassyieldbreakexceptimportnonlocalclasslambdainraisecontinuefinallyisreturndeffor tryTrueFalseNone 

2. Operators

Operators

Operators are special tokens (sequence of characters) that have meaning to the Python Interpreter.  Using them implies some form of mathematical operation. The following is the complete list of Operators. 

()[]{},:.`=;'''#\@ 

3. Punctuators and Delimiters

Punctuators and Delimiters

Punctuators which are also known as delimiters, separate different elements in Python statements and expressions. Here is the complete list:

()[]{},:.`=;'''#\@ 

4.Python Arithmetic Operators

OperatorMeaningUsage+Addition or unary plusx + y-Subtraction or unary minusx - y*Multiplicationx * y/Division (result is always a float)x / y%Modulusx % y (remainder of x/y)//Floor division - results into whole number (may be float)x // y**Exponentx**y (x to the power y)

5. Python Operators Precedence Table

OperatorDescription**Exponentiation~, +, -Complement, unary plus and unary minus*, /, %, //Multiply, divide, modulo and whole (floor) division+, -Addition and subtraction>>, <<Right and left bitwise shift&Bitwise and^ ,|Bitwise exclusive or and bitwise or<=, < ,> ,>=,Relational operators<> ,== ,!=Equality operators= ,%= ,/= ,//= ,-= ,+= ,*=, **=Assignment operatorsis , is notIdentity operatorsin not inMembership operatorsnot , or , andLogical operators

6.Python Relational Operators

OperatorMeaningUsage>Greater thanx > y<Less thanx < y==Equal tox == y!=Not equal tox != y>=Greater than or equal tox >= y<=Less than or equal to x <= y

7.Python Logical Operators

OperatorMeaningUsageandTrue if both the operands are truex and yorTrue if either of the operands is truex or ynotcomplements the operandnot x

8.Boolean Operators

The basic Boolean operators are: and, or, not . The following is the truth table for each of these operators. Note that A and B in the tables below are the names of the operands that represent a Boolean Expression. 

not A

The not operator flips the value of the Boolean operand. It converts True to False and False to True.

Anot ATrueFalseFalseTrue

A and B

The and operator requires both A and B to be True for the whole expression to be True. If only one of them isFalse then the entire expression is False.

ABA and BTrueTrueTrueTrueFalseFalseFalseTrueFalseFalseFalseFalse

A or B

The or operator only requires one of A or B to be True for the entire expression to be True. The whole expression is False only when neither A nor B is True. 

ABA or BTrueTrueTrueTrueFalseTrueFalseTrueTrueFalseFalseFalse

9.Python Membership Operators

OperatorMeaningUsageinCheck to see if value is in the sequence5 in [2,5,3,7]not inCheck to see if value is not in the sequence5 not in [2,5,3,7]

10.Complete Precedence Table

The following table shows the complete precedence of Python Operators: Highest to Lowest

OPERATORDESCRIPTION()Parenthesis (grouping)f(args...), x[i:i], x[i], x.attrFunction call, slicing, subscript, dot**Exponentiation+, -, ~Unary Positive, Unary Negative, bitwise NOT*, /, %Multiplication, Division, Remainder+, -Addition, Subtraction<<, >>Shifts&Bitwise AND^Bitwise XOR|Bitwise OR<, <=, >, >=, !=, ==, is, is not, in, not inComparisons, identity, membershipnotBoolean NOTandBoolean ANDorBoolean ORlambdaLambda Expression

11.Built-in Functions

The python interpreter has a number of functions built into it that are always available. 

abs()dict()help()min()setattr()all()dir()hex()next()slice()any()divmod()id()object()sorted()ascii()enumerate()input()oct()staticmethod()bin()eval()int()open()str()bool()exec()isinstance()ord()sum()bytearray()filter()issubclass()pow()super()bytes()float()iter()print()tuple()callable()format()len()property()type()chr()frozenset()list()range()vars()classmethod()getattr()locals()repr()zip()compile()globals()map()reversed()__import__()complex()hasattr()max()round() delattr()hash()memoryview()set()

For more information on Built-in Functions, you may look at the Python Documentation. 

12.common list method

Table of common methods for lists

list.append(x)Add an item to the end of the list. Equivalent to a[len(a):] = [x].list.extend(L)Extend the list by appending all the items in the given list. Equivalent to a[len(a):] = L.list.insert(i, x)Insert an item at a given position. The first argument is the index of the element to insert.list.remove(x)Remove the first item from the list whose value is x. It is an error if there is no such item.list.copy()Return a shallow copy of the list. Equivalent to a[:].list.pop([i])Remove the item at the given position and return it. If no index is specified, removes the last item.list.clear()Remove all items from the list. Equivalent to del a[:].list.index(x)Return the index in the list of the first item whose value is x. It is an error if there is no such item.list.count(x)Return the number of times x appears in the list.list.reverse()Reverse the elements of the list in place.list.sort(key=None, reverse=False) Sort the items of the list in place (the arguments can be used for sort customization).

13.Most commonly used UTF-8 Character Codes

Source: wiki

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

 
2
 

SP
0020
32

!
0021
33

"
0022
34

#
0023
35

$
0024
36

%
0025
37

&
0026
38

'
0027
39

(
0028
40

)
0029
41

*
002A
42

+
002B
43

,
002C
44

-
002D
45

.
002E
46

/
002F
47

 
3
 

0
0030
48

1
0031
49

2
0032
50

3
0033
51

4
0034
52

5
0035
53

6
0036
54

7
0037
55

8
0038
56

9
0039
57

:
003A
58

;
003B
59

<
003C
60

=
003D
61

>
003E
62

?
003F
63

 
4
 

@
0040
64

A
0041
65

B
0042
66

C
0043
67

D
0044
68

E
0045
69

F
0046
70

G
0047
71

H
0048
72

I
0049
73

J
004A
74

K
004B
75

L
004C
76

M
004D
77

N
004E
78

O
004F
79

 
5
 

P
0050
80

Q
0051
81

R
0052
82

S
0053
83

T
0054
84

U
0055
85

V
0056
86

W
0057
87

X
0058
88

Y
0059
89

Z
005A
90

[
005B
91

\
005C
92

]
005D
93

^
005E
94

_
005F
95

 
6
 

`
0060
96

a
0061
97

b
0062
98

c
0063
99

d
0064
100

e
0065
101

f
0066
102

g
0067
103

h
0068
104

i
0069
105

j
006A
106

k
006B
107

l
006C
108

m
006D
109

n
006E
110

o
006F
111

 
7
 

p
0070
112

q
0071
113

r
0072
114

s
0073
115

t
0074
116

u
0075
117

v
0076
118

w
0077
119

x
0078
120

y
0079
121

z
007A
122

{
007B
123

|
007C
124

}
007D
125

~
007E
126

DEL
007F
127

14.Table of ASCII Control Characters

DecimalHexadecimalBinaryCharacterDescription000NULnull111SOHstart of header2210STXstart of text3311ETXend of text44100EOTend of transmission55101ENQenquiry66110ACKacknowledge77111BELbell881000BSbackspace991001HThorizontal tab100A1010LFline feed110B1011VTvertical tab120C1100FFform feed130D1101CRenter / carriage return140E1110SOshift out150F1111SIshift in161010000DLEdata link escape171110001DC1device control 1181210010DC2device control 2191310011DC3device control 3201410100DC4device control 4211510101NAKnegative acknowledge221610110SYNsynchronize231710111ETBend of trans. block241811000CANcancel251911001EMend of medium261A11010SUBsubstitute271B11011 ESCescape281C11100 FSfile separator291D11101GSgroup separator301E11110RSrecord separator311F11111USunit separator

15.Table of printable ASCII Characters

Decimal

Hexadecimal

BinaryCharacterDescription3220100000Spacespace3321100001!exclamation mark3422100010"double quote3523100011#number3624100100$dollar3725100101%percent3826100110&ampersand3927100111'single quote4028101000(left parenthesis4129101001)right parenthesis422A101010*asterisk432B101011+plus442C101100,comma452D101101-minus462E101110.period472F101111/slash48301100000zero49311100011one50321100102two51331100113three52341101004four53351101015five54361101106six55371101117seven56381110008eight57391110019nine583A111010:colon593B111011;semicolon603C111100<less than613D111101=equality sign623E111110>greater than633F111111?question mark64401000000@at sign65411000001A 66421000010B 67431000011C 68441000100D 69451000101E 70461000110F 71471000111G 72481001000H 73491001001I 744A1001010J 754B1001011K 764C1001100L 774D1001101M 784E1001110N 794F1001111O 80501010000P 81511010001Q 82521010010R 83531010011S 84541010100T 85551010101U 86561010110V 87571010111W 88581011000X 89591011001Y 905A1011010Z 915B1011011[left square bracket925C1011100\backslash935D1011101]right square bracket945E1011110^caret / circumflex955F1011111_underscore96601100000`grave / accent97611100001a 98621100010b 99631100011c 100641100100d 101651100101e 102661100110f 103671100111g 104681101000h 105691101001i 1066A1101010j 1076B1101011k 1086C1101100l 1096D1101101m 1106E1101110n 1116F1101111o 112701110000p 113711110001q 114721110010r 115731110011s 116741110100t 117751110101u 118761110110v 119771110111w 120781111000x 121791111001y 1227A1111010z 1237B1111011{left curly bracket1247C1111100|vertical bar1257D1111101}right curly bracket1267E1111110~tilde1277F1111111DELdelete

16.string methods

                     Method                                              Descriptions.capitalize()The first character of s is put in uppercases.center([width])Centers s in a field of length widths.count(sub [,start [, end]])Counts occurrences of sub between start and ends.encode([encoding [, errors]])Encode s using encoding as code and errors.expandtabs([tabsize])Expands tabss.find(sub [, start [, end]])Finds the first occurrence of sub between start and ends.index(sub [,start [, end]])same as find but raises an exception if no occurrence is founds.islower()Returns True if all chracters are lowercase, False otherwises.isupper()Returns True if all chracters are uppercase, False otherwises.join(words)Joins the list of words with s as delimiters.ljust(width)Left align s in a string of length widths.lower()Returns a lowercase version of ss.lstrip()Removes all leading whitespace characters of ss.replace(old, new [, maxrep])Replace maximal maxrep versions of substring old with substring news.rfind(sub [, start [, end]])Finds the last occurrence of substring sub between start and ends.rindex(sub [,start [, end]])Same as rfind but raise an exception if sub does not existss.rjust(width)Right-align s in a string of length widths.rstrip()Removes trailing whitespace characterss.split([sep [, maxsplit]]))Split s into maximal maxsplit words using sep as separator (default whitespace)s.splitlines([keepends])Split s into lines, if keepends is 1 keep the trailing newlines.strip()Removes trailing and leading whitespace characterss.swapcase()Returns a copy of s with lowercase letters turn into uppercase and vice versas.title()Returns a title-case version of s (all words capitalized)s.upper()Returns an uppercase version of s

17.common methods for Dictionaries

Table of common methods for Dictionaries

Method Name

Descriptiondict.clear()Removes all elements of dictionary.dict.copy()Returns a shallow copy of dictionary.dict.fromkeys(seq[,value])Create a new dictionary with keys from seq and values set to value.dict.get(key, default=None)For key key, returns value or default if key not in dictionarydict.items()Returns a view object of dict items.dict.keys()Returns a view object of dict keys.dict.pop(key)Remove key, Return valuedict.setdefault(key, default=None)Similar to get(), but will set dict[key]=default if key is not already in dictdict.update(dict2)Adds dictionary dict2's key-values pairs to dictdict.values()Returns a view object of dict_values.

18.File access Modes

File access Modes

ModeDescriptionrOpens a file for reading only. This is the default mode.rbOpens a file for reading only in binary formatr+Opens a file for both reading and writing. rb+Opens a file for both reading and writing in binary format. wOpens a file for writing only. Overwrites the file if the file exists. Create a new file if it does not exist.wbOpens a file for writing only in binary format. w+Opens a file for both writing and reading. Overwrites the file if the file exists. Create a new file if it does not exist.wb+Opens a file for both writing and reading in binary format. aOpens a file for appending. The file pointer is at the end of the file if the file exists. abOpens a file for appending in binary format. a+Opens a file for both appending and reading. ab+Opens a file for both appending and reading in binary format. 

19. Common File Methods

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Common File Functions and Methods

Methods and FunctionsDescriptionopen()returns a file object, and is most commonly used with two arguments: open(filename, mode).file.close()Close the filefile.read([size])  Read entire file. If size is specified then read at most size bytes.file.readline([size])Read one line from file. If size is specified then read at most size bytes.file.readlines([size]) Read all the lines from the file and return a list of lines. If size is specified then read at most size bytes.file.write()Writes the contents of string to the file, returning the number of characters written.file.tell()Returns an integer giving the file object’s current position in the filefile.seek()Changes the file object’s position

20.String Formatting

String Formatting

SymbolDescriptionbFormat an integer in binary. cGiven a number, display the character that has that code. dDisplay a number in decimal (base 10). eDisplay a float value using the exponential format. ESame as e, but use a capital “E” in the exponent. fFormat a number in fixed-point form. gGeneral numeric format: use either f or g, whichever is appropriate. GSame as “g”, but uses a capital “E” in the exponential form. nFor formatting numbers, this format uses the current local setting to insert separator characters.oDisplay an integer in octal format. xDisplay an integer in hexadecimal (base 16). Digits greater than 9 are displayed as lowercase characters. XDisplay an integer in hexadecimal (base 16). Digits greater than 9 are displayed as uppercase characters. %Display a number as a percentage: its value is multiplied by 100, followed by a “%” character. 

21.String Formatting Example

String Formatting Example Table

Number Format Output Description 3.1415926{:.2f} 3.142 decimal places 3.1415926{:+.2f} 3.142 decimal places with sign -1{:+.2f} -12 decimal places with sign 2.71828{:.0f} 3No decimal places 5{:0>2d} 5Pad number with zeros (left padding, width 2) 5{:x<4d} 5xxx Pad number with x's (right padding, width 4) 10{:x<4d} 10xx Pad number with x's (right padding, width 4) 1000000{:,} 1,000,000Number format with comma separator 0.25{:.2%} 25.00%Format percentage 1E+09{:.2e} 1.00E+09Exponent notation 13{:10d} 13Right aligned (default, width 10) 13{:<10d} 13Left aligned (width 10)13{:^10d} 13 Center aligned (width 10) 

22. Standard Exceptions

EXCEPTION NAMEDESCRIPTIONArithmeticErrorBase class for all errors that occur for numeric calculation.AssertionErrorRaised in case of failure of the Assert statement.AttributeErrorRaised in case of failure of attribute reference or assignment.EnvironmentErrorBase class for all exceptions that occur outside the Python environment.EOFErrorRaised when there is no input from either the raw_input() or input() function and the end of file is reached.ExceptionBase class for all exceptionsFloatingPointErrorRaised when a floating point calculation fails.ImportErrorRaised when an import statement fails.IndentationErrorRaised when indentation is not specified properly.IndexErrorRaised when an index is not found in a sequence.IOErrorRaised when an input/ output operation fails, such as the print statement or the open() function when trying to open a file that does not exist.IOErrorRaised for operating system-related errors.KeyboardInterruptRaised when the user interrupts program execution, usually by pressing Ctrl+c.KeyErrorRaised when the specified key is not found in the dictionary.LookupErrorBase class for all lookup errors.NameErrorRaised when an identifier is not found in the local or global namespace.NotImplementedErrorRaised when an abstract method that needs to be implemented in an inherited class is not actually implemented.OverflowErrorRaised when a calculation exceeds maximum limit for a numeric type.Raised when Python interpreter is quit by using the sys.exit() function. If not handled in the code, causes the interpreter to exit.Raised when an operation or function is attempted that is invalid for the specified data type.RuntimeErrorRaised when a generated error does not fall into any category.StandardErrorBase class for all built-in exceptions except StopIteration and SystemExit.StopIterationRaised when the next() method of an iterator does not point to any object.SyntaxErrorRaised when there is an error in Python syntax.SystemErrorRaised when the interpreter finds an internal problem, but when this error is encountered the Python interpreter does not exit.SystemExitRaised by the sys.exit() function.SystemExitRaised when Python interpreter is quit by using the sys.exit() function. If not handled in the code, causes the interpreter to exit.UnboundLocalErrorRaised when trying to access a local variable in a function or method but no value has been assigned to it.ValueErrorRaised when the built-in function for a data type has the valid type of arguments, but the arguments have invalid values specified.ZeroDivisonErrorRaised when division or modulo by zero takes place for all numeric types.