basic doc : loops and operators

Docs/Basic/03-loops.md

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+### **1. Looping Through a List**
+
+```python
+list = [1, 2, 3, 5, 9, 'abbas']
+for item in list:
+    print(f'Item In List: {item}')
+```
+
+**Explanation:**
+- A `list` is a collection of items in Python, enclosed in square brackets `[]`.
+- The `for` loop iterates over each element in the list.
+- `item` is a variable that takes the value of each element in the list one by one.
+- `print(f'Item In List: {item}')` uses an f-string to display the current item.
+
+**Output:**
+```
+Item In List: 1
+Item In List: 2
+Item In List: 3
+Item In List: 5
+Item In List: 9
+Item In List: abbas
+```
+
+---
+
+### **2. Looping Through a String**
+
+```python
+string = "abbas gholi"
+for char_string in string:
+    print(char_string)
+```
+
+**Explanation:**
+- A `string` is a sequence of characters.
+- The `for` loop iterates over each character in the string.
+- `char_string` is a variable that holds each character in turn.
+- Each character is printed on a new line.
+
+**Output:**
+```
+a
+b
+b
+a
+s
+ 
+g
+h
+o
+l
+i
+```
+
+---
+
+### **3. Looping Through a Dictionary**
+
+```python
+price = {
+    "oil": 500000,
+    "egg": 350000,
+    "frute": {
+        "apple": 100000,
+        "orange": 120000
+    }
+}
+```
+
+This is a dictionary with:
+- Keys: `"oil"`, `"egg"`, `"frute"`
+- Values: numbers and another dictionary
+
+#### **Method 1: Looping Over Keys**
+
+```python
+for name in price:
+    print(name, price[name])
+```
+
+**Explanation:**
+- `for name in price` iterates over the keys of the dictionary.
+- `price[name]` retrieves the value corresponding to the key.
+- Prints each key and its value.
+
+**Output:**
+```
+oil 500000
+egg 350000
+frute {'apple': 100000, 'orange': 120000}
+```
+
+#### **Method 2: Using `.items()`**
+
+```python
+for name, pr in price.items():
+    print(name, pr)
+```
+
+**Explanation:**
+- `.items()` returns key-value pairs as tuples.
+- `name, pr` unpacks each tuple into two variables.
+- More efficient and readable than accessing `price[name]`.
+
+**Output:**
+```
+oil 500000
+egg 350000
+frute {'apple': 100000, 'orange': 120000}
+```
+
+---
+
+### **Summary**
+
+| Concept         | Description |
+|----------------|-------------|
+| **List**       | Ordered collection of items. Use `for item in list` to iterate. |
+| **String**     | Sequence of characters. Use `for char in string` to access each character. |
+| **Dictionary** | Key-value pairs. Use `for key in dict` or `for key, value in dict.items()` to loop. |
+

Docs/Basic/04-operators.md

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+### **1. `for` Loop with `range()`**
+
+```python
+for i in range(2, 20, 1):
+    print(f"i : {i}", end=" End \n")
+```
+
+- **`range(start, stop, step)`**: Generates a sequence of numbers starting from `start` (inclusive), up to `stop` (exclusive), increasing by `step`.
+  - `range(2, 20, 1)` → numbers from 2 to 19 (inclusive), step 1.
+- **`for` loop**: Iterates over each number in the range.
+- **`print(f"i : {i}", end=" End \n")`**:
+  - `f-string`: Formats the output with the current value of `i`.
+  - `end=" End \n"`: Replaces the default newline (`\n`) with `" End "` followed by a newline.
+- **Output**: Prints each number with `" End "` at the end of each line.
+
+---
+
+### **2. Looping Through a List Using Index and `enumerate()`**
+
+```python
+list = ['abbas', 'mmd', 2006]
+for key in range(len(list)):
+    value = list[key]
+    print(key, value)
+```
+
+- **`len(list)`**: Returns the number of elements in the list (3).
+- **`range(len(list))`**: Creates numbers `0, 1, 2` (indices of the list).
+- **`list[key]`**: Accesses the element at index `key`.
+- **Output**: Prints index and value pair for each element.
+
+---
+
+```python
+for key, value in enumerate(list):
+    print(key, value)
+```
+
+- **`enumerate(list)`**: Returns pairs of `(index, value)` for each element.
+- **`key, value`**: Unpacks each pair into two variables.
+- **Output**: Same as above, but more concise and Pythonic.
+
+> ✅ **Best Practice**: Use `enumerate()` instead of `range(len())` for cleaner code.
+
+---
+
+### **3. `zip()` Function – Pairing Two Lists**
+
+```python
+name = ['egg', 'oil']
+price = [370000, 500000]
+for final in zip(name, price):
+    print(final)
+```
+
+- **`zip(list1, list2)`**: Combines two lists element-wise into tuples.
+  - `zip(['egg', 'oil'], [370000, 500000])` → `[('egg', 370000), ('oil', 500000)]`
+- **`for final in zip(...)`**: Iterates over each tuple.
+- **Output**: Prints each pair as a tuple.
+
+> ✅ Use `zip()` when you need to process multiple lists in parallel.
+
+---
+
+### Summary of Key Concepts:
+
+| Concept        | Purpose |
+|----------------|--------|
+| `range(start, stop, step)` | Generate a sequence of numbers |
+| `for` loop | Iterate over a sequence |
+| `len(list)` | Get number of elements |
+| `enumerate()` | Get index and value in a loop |
+| `zip()` | Combine two or more lists element-wise |