Test case variables

print(f"input_vars: {input_vars}")
print(f"original_input_vars: {original_input_vars}")
print(f"returned_output_vars: {returned_output_vars}")
print(f"true_output_vars: {true_output_vars}")

Python Dictionary

Dictionaries

Task	Method	Code Snippet	Notes
Dictionary Get	for dictionary safe get	my_dict = {'a': 1, 'b': 2} # Key exists: value_a = my_dict.get('a', 0) 1 # Key does not exist, returns default (0) value_c = my_dict.get('c', 0) 0 # Key does not exist, returns None by default: value_d = my_dict.get('d') None
Dictionary modification	Add item	mydict['new_key'] = 'value'
Dictionary modification	update with multiple	mydict.update( {'key':'v', 'key1':'v1'} )
Dictionary Iteration	Key-Value Pairs (Tuple)	types = [(k, v) for k, v in pois.items()]	Output - list of tuples
Dictionary Iteration	Key-Value Pairs (List)	types = [[k, v] for k, v in pois.items()]	Output - list of lists
Dictionary Iteration	Key-Value Pairs (List)	types = [k:v for k, v in pois.items()]	Output - dictionary
Extracting Keys	Comprehension	types = [k for k, v in pois.items()]
Extracting Keys	Simpler Method	types = list(pois.keys())
Extracting Values	Comprehension	types = [v for k, v in pois.items()]
Extracting Values	Simpler Method	types = list(pois.values())
Unpacking	Keys and Values Separately	keys, values = zip(*pois.items())
Reverse Dictionary	Comprehension	reversed_pois = {v: k for k, v in pois.items()}	If original dictionary has duplicate values the reversed dictionary will only keep the last key processed for that value
Count Occorurences	Count freq	word_list = ['dog', 'cat', 'horse', 'dog'] word_counts = Counter(word_list) print(word_counts) #Output: Counter({'dog': 2, 'cat': 1, 'horse': 1})

List

Task	Method	Code Snippet
Reverse a list	list reverse	new_list = reversed(old_list)
List Append	add items	list_sample.append(5)
List extend	add multiple items	list_sample.extend(list2)
List Insert	Inserts at a position	my_list.insert(1, 'banana')
List Comprehension	Nested Loop Syntax	[expression for outer in outer_list for inner in outer]
Flattening Lists	Flatten nested list	flat_list = [item for sublist in lst for item in sublist]
Use Filter	Use filter in iteration	def is_even(x): # Returns Trueonly ifx is an even integer return (x % 2) == 0 # Filter a sequence, keeping just the even values: for val in filter(is_even, [3, 6, 8, 2, 7, 1, 4, 9, 5, 0]): print(val, end=' ')
Enumerate	to get index and value	for index, fruit in enumerate(fruits): print(f"Index {index}: {fruit}")
List Remove		[ num for num in L if num != x]

Numeric

Task	Method	Code Snippet	Notes
Convert integer to binary	use bin	bin(10)	Returns '0b1010'; the 0b prefix indicates binary. <class 'str'>
Convert integer to binary	Format string	f"{10:b}"	Returns '1010'; removes the 0b prefix automatically.
Convert to Float	float	float(val)

Bitwise operators

Task	Method / Operator	Code Snippet	Logic / Description
Bitwise Operation	Left Shift	x << y	Returns x with bits shifted left by y places. Same as x * 2**y. New bits on the right are zeros.
Bitwise Operation	Right Shift	x >> y	Returns x with bits shifted right by y places. Same as x // 2**y. New bits on the right are zeros.
Bitwise AND	&	a & b	Sets bit to 1 if both bits are 1.
Bitwise OR	|	a | b	Sets bit to 1 if one of the bits is 1.
Bitwise XOR	^	a ^ b	Sets bit to 1 if only one of the bits is 1.
Bitwise NOT	~	~a	Inverts all the bits.

Regular Expression

Task	Method / Operator	Code Snippet	Logic / Description
RegEx Split	Split based on pattern	re.split(pattern, string, maxsplit=0, flags=0)	splits based on the given pattern
RegEx Findall	Returns a list based on the pattern	re.findall(pattern, string)	is ideal when you need to extract all occurrences of a pattern from a text, such as collecting all the numbers, dates, or email addresses in a document.
RegEx Search			is useful for general-purpose scanning when you only need the first instance of a pattern, like finding the first email address in a log file.
RegEx Match			is best for input validation where the entire string needs to follow a specific starting format, such as checking for a specific file prefix or a country code in a phone number.

Tuples

Task	Method / Operator	Code Snippet	Logic / Description

Strings

Task	Method / Operator	Code Snippet	Logic / Description
Format string with thousand separator	Format with specified separator	formatted_streams = f'{streams_avg:,}'	Formats it with , as separator
Remove white space from string		my_string = " Hello World " trimmed_string = my_string.strip()
String Concatination	out_string = f'{string1}{string2}'

Math

Task	Method / Operator	Code Snippet	Logic / Description
Floor Fraction	Floor the fraction	math.floor(a/b)
Ceil Fraction	Ceil a fraction	math.ceil(a/b)
Average	No built in method	( a + b + c ) / 3
Min		import math min(my_list)
Max		import math max(my_list)

Set

Task	Method / Operator	Code Snippet	Logic / Description
Set Intersection	set1.intersection(set2)

references

Bitwise Operators