How to use searching in python with example

How to use searching in python with example

I'm happy to help you with that!

Searching is a fundamental operation in programming, and Python provides several ways to perform searching on various data structures. In this answer, I will cover the most commonly used search methods: linear search, binary search, and search algorithms implemented by Python's built-in data structures.

Linear Search

Linear search, also known as sequential search, is a simple search algorithm that checks each element in a sequence until it finds a match. It starts from the beginning of the sequence and iterates through each element until it either finds the target or reaches the end of the sequence.

Here's an example implementation of linear search:

def linear_search(arr, target):
for i in range(len(arr)):
if arr[i] == target:
return i
return -1  # Not found
arr = [3, 5, 2, 7, 11]
target = 7
result = linear_search(arr, target)
if result != -1:
print(f"Found {target} at index {result}")
else:
print(f"{target} not found in the array")

Binary Search

Binary search is a more efficient algorithm that assumes the data is sorted. It works by repeatedly dividing the search interval in half and searching for the target in one of the two halves.

Here's an example implementation of binary search:

def binary_search(arr, target):
low = 0
high = len(arr) - 1
while low <= high:
mid = (low + high) // 2
if arr[mid] == target:
return mid
elif arr[mid] < target:
low = mid + 1
else:
high = mid - 1
return -1  # Not found
arr = [1, 2, 3, 4, 5, 6, 7]
target = 5
result = binary_search(arr, target)
if result != -1:
print(f"Found {target} at index {result}")
else:
print(f"{target} not found in the array")

Search Algorithms Implemented by Python's Built-in Data Structures

Python's built-in data structures, such as lists and dictionaries, have their own search algorithms implemented:

Here's an example:

my_dict = {"name": "John", "age": 30}
result = my_dict.get("name")
print(result)  # Output: John

These search algorithms are implemented in CPython, which is the default Python interpreter. Other implementations might have slightly different performance characteristics.

Conclusion

In this answer, we covered three main search methods: linear search, binary search, and search algorithms implemented by Python's built-in data structures. Each method has its own strengths and weaknesses, and choosing the right algorithm depends on the specific problem you're trying to solve.

How to do searching in Python?

I'd be happy to help with that! Searching in Python involves using various techniques and libraries to find specific data within a dataset. Here are some common ways to search in Python:

Example:

def linear_search(lst, target):
for i, item in enumerate(lst):
if item == target:
return i
return -1
my_list = [1, 2, 3, 4, 5]
index = linear_search(my_list, 3)
print(index)  # Output: 2

Example:

def binary_search(lst, target):
low, high = 0, len(lst) - 1
while low <= high:
mid = (low + high) // 2
if lst[mid] == target:
return mid
elif lst[mid] < target:
low = mid + 1
else:
high = mid - 1
return -1
my_list = [1, 2, 3, 4, 5]
index = binary_search(my_list, 3)
print(index)  # Output: 2

Example:

my_dict = {'a': 1, 'b': 2, 'c': 3}
key = 'b'
if key in my_dict:
print(f"'{key}' is present in the dictionary.")
else:
print(f"'{key}' is not present in the dictionary.")

Example:

my_set = {1, 2, 3, 4, 5}
target = 3
if target in my_set:
print(f"'{target}' is present in the set.")
else:
print(f"'{target}' is not present in the set.")

Example:

class Person:
def init(self, name):
self.name = name
people = [Person('John'), Person('Mary'), Person('Jane')]
target_person = 'Mary'
for person in people:
if person.name == target_person:
print(f"Found {target_person}!")
break
else:
print(f"{target_person} not found.")

Example:

import pandas as pd
df = pd.DataFrame({'Name': ['John', 'Mary', 'Jane'],
'Age': [25, 30, 35]})
target_person = 'Mary'
result = df.loc[df['Name'] == target_person]
print(result)  # Output:   Name  Age
Mary  30
or
query_result = df.query('Name == "' + target_person + '"')
print(query_result)

These are just a few examples of how to search in Python. The best method for you will depend on the structure and size of your dataset, as well as what you're searching for.