Hướng dẫn check if a character is present in string python - kiểm tra xem một ký tự có trong chuỗi python

Chúng ta hãy giải quyết vấn đề chung này về việc tìm kiếm nếu một chuỗi cụ thể có mặt trong một chuỗi lớn hơn theo những cách khác nhau. Đây là một loại vấn đề rất phổ biến mà mọi lập trình đều xuất hiện ít nhất một lần trong cuộc đời của anh ấy/cô ấy. Bài viết này cung cấp các kỹ thuật khác nhau để giải quyết nó. & NBSP;

Phương pháp 1: Sử dụng toán tử trong toán tử trong toán tử là phương pháp chung, nhanh nhất để kiểm tra phần phụ, sức mạnh của toán tử trong Python rất nổi tiếng và được sử dụng trong nhiều hoạt động trên toàn bộ ngôn ngữ. & NBSP; The in operator is the most generic, fastest method to check for a substring, the power of in operator in python is very well known and is used in many operations across the entire language. 

Python3

test_str = "GeeksforGeeks"

print

for is present in GeeksforGeeks

0

for is present in GeeksforGeeks

1

for is present in GeeksforGeeks

2

for is present in GeeksforGeeks

3

for is present in GeeksforGeeks

4

for is present in GeeksforGeeks

5

for is present in GeeksforGeeks

6

for is present in GeeksforGeeks

1

for is present in GeeksforGeeks

8

for is present in GeeksforGeeks

3

forg does not exists in GeeksforGeeks

0

forg does not exists in GeeksforGeeks

1print

forg does not exists in GeeksforGeeks

3

forg does not exists in GeeksforGeeks

4

forg does not exists in GeeksforGeeks

5

forg does not exists in GeeksforGeeks

1print

forg does not exists in GeeksforGeeks

8

forg does not exists in GeeksforGeeks

9

for is present in GeeksforGeeks

0

Đầu ra:

Does for exists in GeeksforGeeks ? : 
Yes, String found

Phương pháp 2: Sử dụng phương thức str.find [] str.find [] thường được sử dụng để có chỉ số thấp nhất mà chuỗi xảy ra, nhưng cũng trả về -1, nếu chuỗi không có, do đó nếu có bất kỳ giá trị nào trả về> = 0, Chuỗi có mặt, khác không có mặt. & nbsp; & nbsp; str.find[] method is generally used to get the lowest index at which the string occurs, but also returns -1, if string is not present, hence if any value returns >= 0, string is present, else not present. 
 

Python3

test_str = "GeeksforGeeks"

print

for is present in GeeksforGeeks

0

for is present in GeeksforGeeks

1

for is present in GeeksforGeeks

2

for is present in GeeksforGeeks

3

for is present in GeeksforGeeks

4

for is present in GeeksforGeeks

5

for is present in GeeksforGeeks

6

for is present in GeeksforGeeks

1

for is present in GeeksforGeeks

8

for is present in GeeksforGeeks

3

forg does not exists in GeeksforGeeks

0

forg does not exists in GeeksforGeeks

1print

forg does not exists in GeeksforGeeks

3

forg does not exists in GeeksforGeeks

4

forg does not exists in GeeksforGeeks

5

forg does not exists in GeeksforGeeks

1print

forg does not exists in GeeksforGeeks

8

forg does not exists in GeeksforGeeks

9

for is present in GeeksforGeeks

0

Đầu ra:

for is present in GeeksforGeeks

Phương pháp 2: Sử dụng phương thức str.find [] str.find [] thường được sử dụng để có chỉ số thấp nhất mà chuỗi xảy ra, nhưng cũng trả về -1, nếu chuỗi không có, do đó nếu có bất kỳ giá trị nào trả về> = 0, Chuỗi có mặt, khác không có mặt. & nbsp; & nbsp;This method can be used to performs the similar task, but like str.find[], it doesn’t return a value, but a ValueError if string is not present, hence catching the exception is the way to check for string in substring. 
 

Python3

test_str = "GeeksforGeeks"

print

for is present in GeeksforGeeks

0

for is present in GeeksforGeeks

1

for is present in GeeksforGeeks

2

for is present in GeeksforGeeks

3

for is present in GeeksforGeeks

4

for is present in GeeksforGeeks

5

for is present in GeeksforGeeks

6

for is present in GeeksforGeeks

1

for is present in GeeksforGeeks

8

for is present in GeeksforGeeks

3

forg does not exists in GeeksforGeeks

0

forg does not exists in GeeksforGeeks

1print

forg does not exists in GeeksforGeeks

3

forg does not exists in GeeksforGeeks

4

forg does not exists in GeeksforGeeks

5

forg does not exists in GeeksforGeeks

1print

forg does not exists in GeeksforGeeks

8

forg does not exists in GeeksforGeeks

9

for is present in GeeksforGeeks

0

Đầu ra:

forg does not exists in GeeksforGeeks

Phương pháp 2: Sử dụng phương thức str.find [] str.find [] thường được sử dụng để có chỉ số thấp nhất mà chuỗi xảy ra, nhưng cũng trả về -1, nếu chuỗi không có, do đó nếu có bất kỳ giá trị nào trả về> = 0, Chuỗi có mặt, khác không có mặt. & nbsp; & nbsp; This is lesser known method to check for substring in a string, this method is also effective in accomplishing this task of checking a string in a string. 
 

Python3

for is present in GeeksforGeeks

4=

for is present in GeeksforGeeks

6

for is present in GeeksforGeeks

1

for is present in GeeksforGeeks

8

test_str = "GeeksforGeeks"

for is present in GeeksforGeeks

5

for is present in GeeksforGeeks

0=

for is present in GeeksforGeeks

2

forg does not exists in GeeksforGeeks

5

forg does not exists in GeeksforGeeks

1print

forg does not exists in GeeksforGeeks

3

forg does not exists in GeeksforGeeks

4

forg does not exists in GeeksforGeeks

5

forg does not exists in GeeksforGeeks

1print

forg does not exists in GeeksforGeeks

8

forg does not exists in GeeksforGeeks

9

for is present in GeeksforGeeks

0

Đầu ra:

for is present in GeeksforGeeks

Phương pháp 2: Sử dụng phương thức str.find [] str.find [] thường được sử dụng để có chỉ số thấp nhất mà chuỗi xảy ra, nhưng cũng trả về -1, nếu chuỗi không có, do đó nếu có bất kỳ giá trị nào trả về> = 0, Chuỗi có mặt, khác không có mặt. & nbsp; & nbsp;This function is used to count the presence of element is the string. We can use this function to check the existence of string in large string. If string exist in string then it return some number else it return 0. 

Python3

test_str = "GeeksforGeeks"

for is present in GeeksforGeeks

4=

for is present in GeeksforGeeks

6

for is present in GeeksforGeeks

1

for is present in GeeksforGeeks

8

for is present in GeeksforGeeks

5

for is present in GeeksforGeeks

0=

for is present in GeeksforGeeks

2

forg does not exists in GeeksforGeeks

5

forg does not exists in GeeksforGeeks

1print

for is present in GeeksforGeeks

6

for is present in GeeksforGeeks

1

for is present in GeeksforGeeks

8

for is present in GeeksforGeeks

9

for is present in GeeksforGeeks

3

forg is not present in GeeksforGeeks

1

forg does not exists in GeeksforGeeks

1print

for is present in GeeksforGeeks

6

for is present in GeeksforGeeks

1

for is present in GeeksforGeeks

8

forg does not exists in GeeksforGeeks

9

for is present in GeeksforGeeks

9

for is present in GeeksforGeeks

3

forg is not present in GeeksforGeeks

1

forg does not exists in GeeksforGeeks

4

forg does not exists in GeeksforGeeks

5

forg does not exists in GeeksforGeeks

1print

forg does not exists in GeeksforGeeks

8

forg does not exists in GeeksforGeeks

9

for is present in GeeksforGeeks

0

Output:

for is present in GeeksforGeeks

Đầu ra:re.search[] function is used to search for an pattern in string. We can use sub-string as a pattern to search in string. 

Python3

Phương pháp 2: Sử dụng phương thức str.find [] str.find [] thường được sử dụng để có chỉ số thấp nhất mà chuỗi xảy ra, nhưng cũng trả về -1, nếu chuỗi không có, do đó nếu có bất kỳ giá trị nào trả về> = 0, Chuỗi có mặt, khác không có mặt. & nbsp; & nbsp;

test_str = "GeeksforGeeks"

for is present in GeeksforGeeks

4=

for is present in GeeksforGeeks

6

for is present in GeeksforGeeks

1

for is present in GeeksforGeeks

8

for is present in GeeksforGeeks

5

for is present in GeeksforGeeks

0=

for is present in GeeksforGeeks

2

forg does not exists in GeeksforGeeks

5

forg does not exists in GeeksforGeeks

1print

for is present in GeeksforGeeks

6

for is present in GeeksforGeeks

1

for is present in GeeksforGeeks

8

for is present in GeeksforGeeks

9

for is present in GeeksforGeeks

3

forg is not present in GeeksforGeeks

1

forg does not exists in GeeksforGeeks

1print

for is present in GeeksforGeeks

6

for is present in GeeksforGeeks

1

for is present in GeeksforGeeks

8

forg does not exists in GeeksforGeeks

9

for is present in GeeksforGeeks

9

for is present in GeeksforGeeks

3

forg is not present in GeeksforGeeks

1

forg does not exists in GeeksforGeeks

4

forg does not exists in GeeksforGeeks

5

forg does not exists in GeeksforGeeks

1print

forg does not exists in GeeksforGeeks

8

forg does not exists in GeeksforGeeks

9

for is present in GeeksforGeeks

0

Output:

forg is not present in GeeksforGeeks

Đầu ra: Using list comprehension 

Python3

for is present in GeeksforGeeks

62=

for is present in GeeksforGeeks

64

for is present in GeeksforGeeks

65=

for is present in GeeksforGeeks

67

Phương pháp 2: Sử dụng phương thức str.find [] str.find [] thường được sử dụng để có chỉ số thấp nhất mà chuỗi xảy ra, nhưng cũng trả về -1, nếu chuỗi không có, do đó nếu có bất kỳ giá trị nào trả về> = 0, Chuỗi có mặt, khác không có mặt. & nbsp; & nbsp;

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