Type conversion (int, float, string) in Python - Step-by-Step Execution

Concept Flow - Type conversion (int, float, string)

Start with a value

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Choose conversion type

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int()

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Converted value of chosen type

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Use value

Start with a value, pick a conversion function (int, float, or str), convert the value, then use the new type.

Execution Sample

Python

x = '123'
y = int(x)
z = float(y)
s = str(z)

Convert string '123' to int, then to float, then back to string.

Execution Table

Step	Variable	Value Before	Conversion Function	Value After	Type After
1	x	None	Assign '123'	'123'	str
2	y	'123'	int(x)	123	int
3	z	123	float(y)	123.0	float
4	s	123.0	str(z)	'123.0'	str
5	-	-	-	-	End of conversions

💡 All conversions done, final value s is string '123.0'

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4
x	None	'123'	'123'	'123'	'123'
y	None	None	123	123	123
z	None	None	None	123.0	123.0
s	None	None	None	None	'123.0'

Key Moments - 3 Insights

Why does int('123') work but int('123.0') causes an error?

int() expects a string that looks like a whole number. '123' works (see step 2), but '123.0' is a decimal string and causes an error.

Does converting int to float change the value?

No, converting int 123 to float 123.0 keeps the number the same but changes its type (see step 3).

Why does str() add quotes around the value?

str() creates a string representation. The quotes show it's a string type (see step 4). The actual value is '123.0' without quotes in memory.

Visual Quiz - 3 Questions

Look at the execution table, what is the type of variable y after step 2?

A str

B float

C int

D None

💡 Hint

Check the 'Type After' column in row for step 2.

At which step does the variable z get assigned a float value?

A Step 2

B Step 3

C Step 1

D Step 4

💡 Hint

Look at the 'Conversion Function' and 'Type After' columns for variable z.

If we tried int('123.0') instead of int('123'), what would happen?

A It raises an error

B It converts successfully to 123

C It converts to 123.0 as float

D It converts to string '123.0'

💡 Hint

Recall the key moment about int() conversion from string with decimal.

Concept Snapshot

Type conversion changes a value's type using int(), float(), or str().
int() converts to whole numbers, float() to decimals, str() to text.
Conversions must be valid (e.g., int('123') works, int('123.0') errors).
Use conversions to change data types for calculations or display.

Full Transcript

This lesson shows how Python converts values between int, float, and string types. We start with a string '123', convert it to an integer 123, then to a float 123.0, and finally back to a string '123.0'. Each step changes the variable's type and value representation. We see that int() requires a string without decimals, float() can convert integers to decimals, and str() turns numbers into text. Understanding these conversions helps when you need to do math or show numbers as text.