Substring Search Patterns in DSA Python - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the pattern exists in the text using the 'in' keyword.

DSA Python

text = "hello world"
pattern = "world"
if pattern [1] text:
    print("Pattern found")
else:
    print("Pattern not found")

Drag options to blanks, or click blank then click option'

Anot in

Bin

C==

Dis

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of 'in' to check substring.

Using 'is' which checks object identity, not substring.

The 'in' keyword checks if the pattern is a substring of the text.

2fill in blank

medium

Complete the code to find the first index of the pattern in the text using the find() method.

DSA Python

text = "abracadabra"
pattern = "cad"
index = text.[1](pattern)
print(index)

Drag options to blanks, or click blank then click option'

Afind

Bindex

Csearch

Dlocate

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'index' which raises an error if substring not found.

Using non-existent methods like 'search' or 'locate'.

The find() method returns the lowest index of the substring if found, else -1.

3fill in blank

hard

Fix the error in the code to correctly count occurrences of the pattern in the text.

DSA Python

text = "banana"
pattern = "ana"
count = text.[1](pattern)
print(count)

Drag options to blanks, or click blank then click option'

Afind

Bindex

Ccount

Dsearch

Attempts:

3 left

💡 Hint

Common Mistakes

Using find() which returns only the first index.

Using index() which raises error if substring not found.

The count() method returns the number of non-overlapping occurrences of the substring.

4fill in blank

hard

Fill both blanks to create a dictionary of patterns and their counts from a list of words.

DSA Python

words = ["apple", "banana", "apple", "cherry"]
pattern_counts = {word: words.[1](word) for word in words if "a" [2] word}
print(pattern_counts)

Drag options to blanks, or click blank then click option'

Acount

Bfind

Cin

Dnot in

Attempts:

3 left

💡 Hint

Common Mistakes

Using find() instead of count() for counting.

Using 'not in' instead of 'in' to filter words.

Use count() to count occurrences and 'in' to check if 'a' is in the word.

5fill in blank

hard

Fill all three blanks to create a dictionary of uppercase patterns and their first index in text if found.

DSA Python

text = "hello world"
patterns = ["he", "wo", "or"]
result = {pattern.[1](): text.[2](pattern) for pattern in patterns if text.[3](pattern) != -1}
print(result)

Drag options to blanks, or click blank then click option'

Aupper

Bfind

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using count() instead of find() for index.

Using upper() incorrectly or missing it.

Use upper() to uppercase pattern, find() to get index, and find() to check presence.