Dictionaries

Topics: dictionary, store values, key-value pairs

Dictionaries store data in key-value pairs. They’re perfect for organizing related information!

Creating Dictionaries

Dictionaries are great for storing structured data — like a patient’s demographic information, diagnosis, and vital signs — all in one variable.

# Empty dictionary
empty_dict = {}

# Dictionary with data
patient_record = {
    "name": "John Doe",
    "age": 45,
    "sex": "Male",
    "diagnosis": "Hypertension",
    "bp": "140/90",
    "is_admitted": True
}

print(patient_record)
# {'name': 'John Doe', 'age': 45, 'sex': 'Male', 'diagnosis': 'Hypertension', 'bp': '140/90', 'is_admitted': True}
Accessing Dictionary Values
print(patient_record["diagnosis"])              # Hypertension
print(patient_record.get("bp"))                 # 140/90
print(patient_record.get("heart_rate", "N/A"))  # N/A (Default if key doesn't exist)

This is like checking a patient’s chart — if a piece of information doesn’t exist, Python can return a default value (e.g., “N/A”).

Modifying Dictionaries

Adding/updating values

patient_record["bp"] = "130/85"        # Update blood pressure
patient_record["heart_rate"] = 72      # Add new key-value pair

print(patient_record)
# {'name': 'John Doe', 'age': 45, 'sex': 'Male', 'diagnosis': 'Hypertension', 'bp': '130/85', 'is_admitted': True, 'heart_rate': 72}

Removing items

del patient_record["is_admitted"]
removed_value = patient_record.pop("heart_rate", "Not found")

print(patient_record)
# {'name': 'John Doe', 'age': 45, 'sex': 'Male', 'diagnosis': 'Hypertension', 'bp': '130/85'}
Dictionary Methods

Get the keys

print(patient_record.keys())     # dict_keys(['name', 'age', 'sex', 'diagnosis', 'bp'])

Get the values

print(patient_record.values())   # dict_values(['John Doe', 45, 'Male', 'Hypertension', '130/85'])

Get the item pairs

print(patient_record.items())    # dict_items([('name', 'John Doe'), ('age', 45), ('sex', 'Male'), ('diagnosis', 'Hypertension'), ('bp', '130/85')])

Check if key exists

print("diagnosis" in patient_record)  # True
print("temperature" in patient_record)  # False

In hospital data systems, you might check if certain patient information (like temperature or lab_results) exists before performing calculations or updates.

Lists String Formatting