Ревізії Binning

kristofer ревизій цього gist 1763751204. До ревизії

1 file changed, 111 insertions

binning.md(файл створено)

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1	+	## Binning of frequencies
2	+
3	+
4	+	Examples of python and java of using dict/hashmap for binning of 1) dice rolls,
5	+	2) letter frequency and 3) checking for existing keys.
6	+
7	+	### Key patterns:
8	+
9	+	- Python: dict.get(key, default) and defaultdict(int) are idiomatic
10	+	- Java: map.getOrDefault(key, default) and map.merge() are modern approaches
11	+	- Both languages support checking key existence before accessing
12	+
13	+
14	+	### in Python
15	+
16	+	```python
17	+	# 1) Dice rolls - counting occurrences
18	+	from collections import defaultdict
19	+	import random
20	+
21	+	# Using defaultdict (cleaner)
22	+	dice_counts = defaultdict(int)
23	+	for _ in range(100):
24	+	roll = random.randint(1, 6)
25	+	dice_counts[roll] += 1
26	+	# Result: {1: 15, 2: 18, 3: 17, 4: 16, 5: 19, 6: 15}
27	+
28	+	# Using regular dict
29	+	dice_counts = {}
30	+	for _ in range(100):
31	+	roll = random.randint(1, 6)
32	+	dice_counts[roll] = dice_counts.get(roll, 0) + 1
33	+
34	+	# 2) Letter frequency
35	+	text = "hello world"
36	+	letter_freq = {}
37	+	for char in text.lower():
38	+	if char.isalpha():
39	+	letter_freq[char] = letter_freq.get(char, 0) + 1
40	+	# Result: {'h': 1, 'e': 1, 'l': 3, 'o': 2, 'w': 1, 'r': 1, 'd': 1}
41	+
42	+	# 3) Checking for existing keys
43	+	inventory = {'apples': 5, 'bananas': 3}
44	+
45	+	# Method 1: using 'in'
46	+	if 'apples' in inventory:
47	+	print(f"Have {inventory['apples']} apples")
48	+
49	+	# Method 2: using get() with default
50	+	oranges = inventory.get('oranges', 0) # Returns 0 if not found
51	+
52	+	# Method 3: try/except
53	+	try:
54	+	count = inventory['oranges']
55	+	except KeyError:
56	+	count = 0
57	+	```
58	+
59	+	### in Java
60	+
61	+	```java
62	+	import java.util.*;
63	+
64	+	// 1) Dice rolls - counting occurrences
65	+	Map<Integer, Integer> diceCount = new HashMap<>();
66	+	Random rand = new Random();
67	+
68	+	for (int i = 0; i < 100; i++) {
69	+	int roll = rand.nextInt(6) + 1;
70	+	diceCount.put(roll, diceCount.getOrDefault(roll, 0) + 1);
71	+	}
72	+	// Result: {1=15, 2=18, 3=17, 4=16, 5=19, 6=15}
73	+
74	+	// Alternative using merge()
75	+	for (int i = 0; i < 100; i++) {
76	+	int roll = rand.nextInt(6) + 1;
77	+	diceCount.merge(roll, 1, Integer::sum);
78	+	}
79	+
80	+	// 2) Letter frequency
81	+	String text = "hello world";
82	+	Map<Character, Integer> letterFreq = new HashMap<>();
83	+
84	+	for (char c : text.toLowerCase().toCharArray()) {
85	+	if (Character.isLetter(c)) {
86	+	letterFreq.put(c, letterFreq.getOrDefault(c, 0) + 1);
87	+	}
88	+	}
89	+	// Result: {h=1, e=1, l=3, o=2, w=1, r=1, d=1}
90	+
91	+	// 3) Checking for existing keys
92	+	Map<String, Integer> inventory = new HashMap<>();
93	+	inventory.put("apples", 5);
94	+	inventory.put("bananas", 3);
95	+
96	+	// Method 1: using containsKey()
97	+	if (inventory.containsKey("apples")) {
98	+	System.out.println("Have " + inventory.get("apples") + " apples");
99	+	}
100	+
101	+	// Method 2: using getOrDefault()
102	+	int oranges = inventory.getOrDefault("oranges", 0); // Returns 0 if not found
103	+
104	+	// Method 3: checking null
105	+	Integer count = inventory.get("oranges");
106	+	if (count == null) {
107	+	count = 0;
108	+	}
109	+	```
110	+
111	+

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