Kiểm tra xem từ không có trong chuỗi python

Trong bài viết này, chúng tôi sẽ đề cập đến cách kiểm tra xem một chuỗi Python có chứa một chuỗi hoặc chuỗi con khác hay không trong Python. Đưa ra hai chuỗi, kiểm tra xem chuỗi con có tồn tại trong chuỗi đã cho hay không.  

Example 1: Input : Substring = "geeks" 
           String="geeks for geeks"
Output : yes
Example 2: Input : Substring = "geek"
           String="geeks for geeks"
Output : yes

Python có chuỗi chứa phương thức chuỗi con không

Có, Kiểm tra chuỗi con là một trong những tác vụ được sử dụng nhiều nhất trong python. Python sử dụng nhiều phương thức để kiểm tra một chuỗi chứa một chuỗi con như find(), index(), count(), v.v. Phương pháp nhanh và hiệu quả nhất là sử dụng toán tử “in” được sử dụng làm toán tử so sánh. Ở đây chúng tôi sẽ đề cập đến các cách tiếp cận khác nhau như

• Sử dụng if… trong
• Kiểm tra bằng phương thức split()
• Sử dụng phương thức find()
• Sử dụng phương thức “count()”
• Sử dụng phương thức index()
• Sử dụng __contains__” lớp ma thuật
• Sử dụng biểu thức chính quy

Phương pháp 1. Kiểm tra chuỗi con bằng cách sử dụng if… in

Python3

Yes! it is present in the string

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Yes! it is present in the string

Đầu ra

Yes! it is present in the string

Phương pháp 2. Kiểm tra chuỗi con bằng phương thức split()

Kiểm tra xem chuỗi con có trong chuỗi đã cho hay không mà không sử dụng bất kỳ hàm sẵn có nào. Đầu tiên chia chuỗi đã cho thành các từ và lưu trữ chúng trong một biến s sau đó sử dụng điều kiện if, kiểm tra xem chuỗi con có tồn tại trong chuỗi đã cho hay không

Python3

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

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Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Đầu ra

Yes! it is present in the string

Phương pháp 3. Kiểm tra chuỗi con bằng phương thức find()

Chúng ta có thể kiểm tra lặp đi lặp lại mọi từ, nhưng Python cung cấp cho chúng ta một hàm sẵn có find() để kiểm tra xem chuỗi con có tồn tại trong chuỗi hay không, việc này được thực hiện trong một dòng. Hàm find() trả về -1 nếu không tìm thấy, ngược lại nó trả về lần xuất hiện đầu tiên, vì vậy sử dụng hàm này vấn đề này có thể được giải quyết.  

Python3

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

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Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Đầu ra

Yes! it is present in the string

Phương pháp 4. Kiểm tra chuỗi con bằng phương thức “count()”

Bạn cũng có thể đếm số lần xuất hiện của một chuỗi con cụ thể trong một chuỗi, sau đó bạn có thể sử dụng phương thức đếm() của Python. Nếu chuỗi con không được tìm thấy thì “có” sẽ được in ra nếu không thì “không sẽ được in ra”

Python3

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

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Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Đầu ra

Yes! it is present in the string

Phương pháp 5. Kiểm tra chuỗi con bằng phương thức index()

Các. phương thức index() trả về chỉ mục bắt đầu của chuỗi con được truyền dưới dạng tham số. Ở đây "chuỗi con" có mặt ở chỉ số 16

Python3

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

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Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

đầu ra

Yes! it is present in the string

Phương pháp 6. Kiểm tra chuỗi con bằng cách sử dụng lớp phép thuật “__contains__”

Chuỗi Python __contains__(). Phương thức này dùng để kiểm tra xem chuỗi này có nằm trong chuỗi kia hay không.  

Python3

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

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Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Đầu ra

Yes! it is present in the string

Phương pháp 7. Kiểm tra chuỗi con bằng biểu thức chính quy

RegEx có thể được sử dụng để kiểm tra xem một chuỗi có chứa mẫu tìm kiếm đã chỉ định hay không. Python có một gói tích hợp gọi là re, có thể được sử dụng để làm việc với Biểu thức chính quy.  

Python3

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

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Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Đầu ra

Yes! it is present in the string

Phương pháp. Sử dụng hiểu danh sách

Python3

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

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Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Đầu ra

Yes! it is present in the string

Phương pháp. Sử dụng hàm lambda

Python3

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

Yes! it is present in the string

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