Python Basic Datatypes

Learn about Python’s primary datatypes—integers, floats, booleans, strings—and where each is used in analytics.

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Key moments

Integers and Floats — Numbers are categorized as integers (whole) or floating points (decimals).
Checking Data Type — The built-in type() function verifies the data type of a variable or value.
Type Conversion — int() and float() functions convert values between numeric types.
Boolean Values — The Boolean type holds True or False, which must be capitalized.
Defining Strings — Strings are text values enclosed in single or double quotation marks.
Type Mismatch Error — Python raises an error if you try to combine different types (like int and str) using the + operator.
String Conversion — The str() function converts numeric values into text for concatenation.
Handling Quotes — Use differing outer and inner quotes or the backslash escape character to include quotes within a string.
String Concatenation — The plus sign (+) joins two strings, while a comma in print() separates them with a space.
Printing Multiple Values — Listing values separated by commas without print() displays them as a tuple in parentheses.

PDF notes

Bottom line: You will be able to identify, create, and manipulate the four fundamental Python data types: integers, floats, booleans, and strings. You will learn how to check a variable's type, convert between types, and correctly handle text data using various quoting and escape techniques.

This lesson on Python Basic Datatypes is hands-on and example-driven. You will be able to identify, create, and manipulate the four fundamental Python data types: integers, floats, booleans, and strings. You will learn how to check a variable's type, convert between types, and correctly handle text data using various quoting and escape techniques.

What You'll Be Able To Do

Determine the data type of any variable or literal value using the built-in type() function.
Create variables holding numeric (integer and float) values and perform basic type conversions.
Define Boolean variables using the required capitalization for True and False.
Construct complex strings using single quotes, double quotes, and escape characters to handle internal punctuation.
Combine numeric variables and strings into a single output using type conversion and concatenation.

Detailed Concept Walkthrough

1. Numeric Types: Int and Float

Numeric data is categorized into integers (whole numbers) and floats (real numbers with a decimal point). Python automatically infers the type upon assignment.

Mechanism: Integers (int) are positive or negative whole numbers (e.g., 5, -6). Floats (float) are real numbers containing a decimal point (e.g., 4.75).
Under the Hood: Python uses the type() function to verify the data type of a variable or a literal value, returning 'int' or 'float'.
Type Conversion: The built-in functions int() and float() can convert values; int() truncates the decimal part of a float (e.g., int(4.75) becomes 4).

x1 = 5
x2 = 4.75
print(type(x1)) # Output: <class 'int'>
print(int(x2))  # Output: 4 (truncates)

Key Takeaway: Python automatically assigns numeric types, but you must use int() or float() to explicitly change them.

2. Boolean Type: True or False

The Boolean type (bool) represents logical states, corresponding to the machine's binary logic (1s and 0s). A variable can only hold one of two values: True or False.

Syntax Rule: Boolean values must be written with an initial capital letter (True or False).
Mechanism: If True or False are typed in lowercase, Python interprets them as undefined variables, resulting in an error.
Under the Hood: The type() function confirms the variable's type as 'bool'.

x3 = True
print(type(x3)) # Output: <class 'bool'>

Key Takeaway: Always capitalize the first letter of True and False when defining Boolean variables.

3. String Type and Manipulation

Strings (str) are sequences of characters used to represent text data, defined by enclosing the text in quotes.

Syntax Rule: Strings can be defined using either single quotes ('George') or double quotes ("George").
Best Practice: Use differing outer and inner quotes to handle internal punctuation, such as an apostrophe (e.g., "I'm fine").
Escape Characters: A backslash (\) changes the interpretation of the character immediately following it, allowing quotes to be included (e.g., 'I\'m fine').
Concatenation: The plus sign (+) is used to combine (concatenate) two strings.

x4 = 'George'
statement = "I'm fine"
print('Red' + ' ' + 'car') # Concatenation with space

Key Takeaway: Use quotes to define text values, ensuring the outer quotes differ from any internal quotes or using the backslash escape character.

Topics Covered in Python Basic Datatypes

Integers and Floats (0:30 - 1:00) — Numbers are categorized as integers (whole) or floating points (decimals).
Checking Data Type (1:00 - 1:40) — The built-in type() function verifies the data type of a variable or value.
Type Conversion (2:00 - 2:30) — int() and float() functions convert values between numeric types.
Boolean Values (2:40 - 3:30) — The Boolean type holds True or False, which must be capitalized.
Defining Strings (3:45 - 4:30) — Strings are text values enclosed in single or double quotation marks.
Type Mismatch Error (5:00 - 5:45) — Python raises an error if you try to combine different types (like int and str) using the + operator.
String Conversion (5:45 - 6:15) — The str() function converts numeric values into text for concatenation.
Handling Quotes (6:45 - 7:30) — Use differing outer and inner quotes or the backslash escape character to include quotes within a string.
String Concatenation (7:45 - 8:30) — The plus sign (+) joins two strings, while a comma in print() separates them with a space.
Printing Multiple Values (8:30 - 9:00) — Listing values separated by commas without print() displays them as a tuple in parentheses.

Python Cheat Sheet

type(variable) — Checks the data type of a value
```
type(4.75)
```
int(value) — Converts a value into an integer
```
int(4.75)
```
str(value) — Converts a value into a string
```
str(10) + " Dollars"
```
True / False — Boolean values used for logic
```
x3 = True
```
'text' or "text" — Defines a sequence of characters
```
x4 = "George"
```
string1 + string2 — Joins two strings together (concatenation)
```
'Red' + ' car'
```
print(val1, val2) — Prints values separated by a space
```
print('Red', 'car')
```
\' — Escape character for internal quotes
```
print('I\'m fine')
```

Comparison Table

Data Type	Description	Example
Integer (int)	Whole numbers, no decimal point.	5 or -6
Float (float)	Real numbers, includes a decimal point.	4.75
Boolean (bool)	Logical state, must be True or False.	True
String (str)	Sequence of characters (text).	'George'

Common Pitfalls

Mistake: Using lowercase true or false for Boolean values. Avoid: Always capitalize the first letter: True or False.
Mistake: Concatenating a number and a string directly with +. Avoid: Convert the number to a string first using str().
Mistake: Using the same quotes internally and externally for a string. Avoid: Use double quotes outside if the string contains a single quote.
Mistake: Assuming Python knows a word is text without quotes. Avoid: Always enclose text values in single or double quotes.

FAQs

Why does int(4.75) result in 4, not 5? The int() function truncates the decimal part of a float; it does not perform standard mathematical rounding.
Can I use single quotes inside a string defined by single quotes? Yes, but you must precede the inner single quote with a backslash () to escape it, like 'I'm fine'.
Does Python require me to declare variable types? No, Python automatically guesses the type of data you are entering, unlike some other programming languages.
What is the difference between using + and using a comma in the print() function? The + operator concatenates strings without adding spaces; the comma automatically separates printed values with a blank space.

Common pitfalls

Mistake: Using lowercase true or false for Boolean values. Avoid: Always capitalize the first letter: True or False.
Mistake: Concatenating a number and a string directly with +. Avoid: Convert the number to a string first using str().
Mistake: Using the same quotes internally and externally for a string. Avoid: Use double quotes outside if the string contains a single quote.
Mistake: Assuming Python knows a word is text without quotes. Avoid: Always enclose text values in single or double quotes.

Hi and welcome! We at 365 Data Science specialize in data science trainings. We post videos weekly, so you can master indispensable skills for free! Alright, let’s get started! When programming, not only in Python, if you say that a variable has a numeric value, you are being ambiguous. The reason is that numbers can be integers or floating points, also called floats, for instance. Integers are positive or negative whole numbers without a decimal point. Let’s create x 1 and bind to it the value of 5. Now, x1 is an integer. Do you agree? A specific function in Python can prove this is correct. It is called “type”. Within the brackets, we must place the name of the variable whose type of value we want to verify. So, in this case, I’ll type x1. Ok. Shift plus Enter and the result we obtained is “int”, which indicates the value is an integer. The “type” function can also be applied directly to a value instead of a variable. For instance, if I write “type, open parentheses, minus 6, close parentheses”, Python will correctly point out that minus six is an integer. Good. Now, let’s assign the value of 4.75 to a new variable, x 2. I would like to check its type; hence, I will use the type function again. This is a float. Great! Floating points, or as you’ll more frequently hear, floats, are real numbers. Hence, they have a decimal point. 4.75 is such a number; therefore, Python reads it as a float. Let’s look at two other built-in functions. “Int” transforms the variable into an integer. That’s why 4.75 turns into 4. “Float”, instead, will add a decimal point to the integer value and will turn it into a float. Not all variables should assume numeric values. An example of such type of values is the Boolean type. In Python, this means a True or False value, corresponding to the machine’s logic of understanding 1s and 0s, on or off, right or wrong, true or false. Let’s provide an example with a new variable, x3, which is equal to True. Right. The output of the “type” function is ‘bool’, which simply means x3 is a Boolean. An important detail you should remember is you have to type True or False with capital letters! Otherwise, Python won’t recognize your variable as a Boolean and will display an error message. So, to wrap it up, the two Boolean values a variable can have are True or False, and they must be written with capital letters. Strings are text values composed of a sequence of characters. Let’s see how we can create a string in practice. If we ask the machine to display the name George this way, we’ll obtain an error message. Why? Because Python assumes George is the name of a variable to which we have assigned no value. Here’s the magic trick that will correct this mistake. Let’s type single quotation marks around the name George, first. And now, let’s type double quotation marks around it. You see the output values of these two inputs are the same. This is how Python displays text results if you don’t use the print command. Should you use print, the output will be shown with no quotes – you’ll be able to see plain text. If we assign this value to a new variable, let’s say x4, we can obtain its output as we did with the integers and floats. All right, so that’s it. If the values you’d like to assign are not numerical, the quotes can come into play! Assume the variable y is supposed to represent the number of dollars you have in your pocket. In addition, you would like to ask the machine to print out a statement that says “Y dollars”, where y is a number. The proper way to combine the value of y and the string “Dollars” is to use a “plus” sign, as shown here. Let’s execute this cell to check if we are missing something. Apparently, we did not respect the rules of coding in Python. We cannot put different types of variables in the same expression. Y is an integer, and “Dollars” is a string. We can convert y into a string. “String”, s.t.r., is the built-in function we need. Analogically to integers and floats, “string” will convert our number into text, and that will unlock our result. To summarize what we said so far, Python can automatically guess the type of data you are entering. It is within its capabilities to know for sure whether you have assigned an integer, a float, a Boolean, or a string. You need not declare the types of variables explicitly, as you must do in some other programming languages. Python always knows the type of variable. What will happen if you type something like… “I’m fine”? You’ll need the apostrophe in the English syntax, not for the Pythonic one. Observe, if you execute the command like this, you will make a mistake. To avoid that, in such situations, you can distinguish between the two symbols – put the text within double quotes and leave the apostrophe, which technically coincides with the single quote between I and M. Now, you are fine.  An alternative way to do that would be to leave the quotes on the sides and place a back slash before the apostrophe within the phrase, and we’ll still obtain the same correct result. This backslash is called an escape character, as it changes the interpretation of characters immediately after it. And what if we wanted to state “press “Enter””, where we put Enter within inverted commas? Same logic – the outer symbols must differ from the inner ones. Put single quotes on the sides. And you obtain the desired result! Finally, let’s go through a few ways of stating values. Say you wish to print “Red car” on the same line. If I write it like this – two words next to each other, separated by a blank space, I’ll see them attached. One trick would be to put a blank space before the second apostrophe of the first word. Let’s see… nice, that looks like the desired result! Another technique would be to sort of “add” one of the strings to the other by typing in a plus sign between the two, just as we did with the “10-dollar” example a minute ago. Ok. As your intuition probably tells you, if you print this combination instead, you’ll obtain the same outcome, but it won’t have the quotes on the two sides. And… here’s a new trick. I’ll type “print ‘Red’", and then I’ll put a comma, which is called a trailing comma, and Python will print the next word, ‘car’, on the same line, separating the two words with a blank space. Shift plus Enter… great! Let’s print the number 3 next to the number 5. Boom – fantastic! Here it is. What will happen if I don’t use the print command and just list a few integers, floats, and strings separating them with commas? Python will execute the command as expected but will place the values within parentheses. Strictly amazing! Thanks for watching! If you found this video interesting and want to gain an edge in your career, make sure to like, comment, and subscribe! And don’t forget to check out some of our other videos for another quick win in the data science skills department!

Frequently asked questions

Why does int(4.75) result in 4, not 5?

The int() function truncates the decimal part of a float; it does not perform standard mathematical rounding.

Can I use single quotes inside a string defined by single quotes?

Yes, but you must precede the inner single quote with a backslash (\) to escape it, like 'I\'m fine'.

Does Python require me to declare variable types?

No, Python automatically guesses the type of data you are entering, unlike some other programming languages.

What is the difference between using + and using a comma in the print() function?

The + operator concatenates strings without adding spaces; the comma automatically separates printed values with a blank space.

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