Basic Data Types

Topics: data type, int, float, string

Python has several built-in data types, each designed to represent different kinds of information. In healthcare and research, you’ll often deal with patient names (text), ages (numbers), lab results (decimals), and test outcomes (True/False). Understanding these data types helps ensure your analyses are accurate and meaningful.

The Four Main Data Types

Strings (str)

Strings are considered as text data enclosed in single or double quotation marks, and are often used to store text data such as patient names, diagnoses, or remarks in a medical record.

patient_name = 'Maria Santos'
diagnosis = 'Hypertension'
note = 'Patient advised to monitor blood pressure daily.'
Integers (int)

Integers are numbers, specifically whole numbers. These data are numbers that do not contain decimal places. They can be age, heart rate, or number of visits.

patient_age = 45
admission_year = 2025
heart_rate = 78
Floats (float)

Floats represent numeric values with decimals — common in lab values, BMI, etc.

body_temperature = 36.8
blood_glucose = 5.7
bmi = 24.5
Booleans (bool)

Booleans are either ‘True’ or ‘False’ data. For example, whether a patient has diabetes, is pregnant, or is a smoker.

has_allergies = True
is_smoker = False
On to Checking Data Types

You can use the type() function to check the data type of any variable. For example, is a lab result value ‘42’ stored as text or as a number?

result = '42'
print(type(result))  # Output: <class 'str'>

value = 42
print(type(value))  # <class 'int'>
Converting Between Data Types

In many datasets, data imported from hospital systems may be stored as text even if they represent numbers.

Converting them to integers or floats allows you to perform calculations like average age or mean blood glucose.

age_str = "25"
age_int = int(age_str)
print(age_int + 5)       # Output: 30
Integer to string

We can also do vice-versa.

patient_bmi = 22.5
bmi_str = str(patient_bmi)
print('Patient BMI is ' + bmi_str)
String to float
glucose_str = '5.8'
glucose_float = float(glucose_str)
print(glucose_float + 0.2)            # Output: 6.0
Float to integer (truncates decimal)
heart_rate = int(75.6)  # Result: 75

When converting from float to integer, Python removes (truncates) the decimal — this is useful when you only need whole-number data, such as rounding heart rate readings.

Boolean conversions
print(bool(1))       # True → e.g., 1 could represent 'Yes' in a dataset
print(bool(0))       # False → e.g., 0 could represent 'No'
print(bool(''))      # False → No value provided
print(bool('Yes'))   # True → Non-empty string
Variables Operators