Python find() Method

What You’ll Learn

The find() method searches a string for a substring and returns the index of the first match. Unlike index(), it returns -1 when nothing is found—so you can search safely without try/except blocks. It is one of the most-used methods for locating text inside strings.

Definition and Usage

In Python, find() scans a string from left to right looking for a substring. When it finds a match, it returns the starting index (counting from 0). For example, in "Hello, World!", the substring "World" starts at index 7. If the substring does not appear, find() returns -1.

📝 Syntax

The find() method accepts one required and two optional parameters:

string.find(sub, start, end)

Syntax Rules

• sub — the substring to search for (required).
• start — optional start index; search begins here (default 0).
• end — optional end index; search stops before this position.
• Return value — integer index of first match, or -1 if not found.
• Read-only — the original string is never modified.

Examples Gallery

Run these examples in any Python 3 interpreter. Indices start at 0 unless noted.

text = "Hello, World!"
index = text.find("World")

print("Text: ", text)
print("Index:", index)
print("Char: ", text[index])

Text:  Hello, World!
Index: 7
Char:  W

text = "Hello, World!"
index = text.find("Python")

if index == -1:
    print("'Python' was not found.")
else:
    print("Found at index:", index)

'Python' was not found.

text = "Hello, Hello, World!"

first = text.find("Hello")
second = text.find("Hello", 7, 15)

print("First Hello at: ", first)
print("Second Hello at:", second)

First Hello at:  0
Second Hello at: 8

text = "Hello, World!"

print("find('world'):", text.find("world"))
print("find('World'):", text.find("World"))
print("lower find:   ", text.lower().find("world"))

find('world'): -1
find('World'): 7
lower find:    7

text = "Hello, World!"
sub = "Python"

print("find(): ", text.find(sub))

try:
    print("index():", text.index(sub))
except ValueError as e:
    print("index() raised ValueError:", e)

find():  -1
index() raised ValueError: substring not found

🚀 Common Use Cases

• Parse emails — find "@" to split username and domain.
• Log analysis — locate error keywords and extract surrounding text.
• File paths — find the last "." before extracting an extension (often rfind() is better).
• Validation — check that required markers appear in user input.
• Text extraction — find a delimiter, then slice from that index onward.

📝 Notes

• -1 means “not found”—do not use it as a slice index without checking first.
• find() returns only the first match; use a loop or count() for multiple occurrences.
• For the last occurrence, use rfind() instead.
• An empty substring "" always matches at index 0 (or at start when given).

💡 Best Practices