Check if a given string is binary string or not - Python

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A binary string is a string that contains only the characters '0' and '1'. For example, "101010" is a binary string, while "10201" is not. Our task is to check if a given string is a binary string or not.

Using all()

all() function in Python is a built-in method that returns True if all elements of an iterable satisfy a given condition, and False otherwise.

s = "101010000111"
if all(c in '01' for c in s):
    print("Yes")
else:
    print("No")

Yes

Explanation:

• all(c in '01' for c in s): creates a generator that iterates through each character in s.
• Checks if each character belongs to the set {'0','1'}.
• Short-circuit evaluation: all() stops immediately if a character fails the condition, making it fast for large strings.

Using set()

set() can be used to quickly identify the unique characters in a string.

s = "101010000111"
if set(s).issubset({'0', '1'}):
    print("Yes")
else:
    print("No")

Yes

Explanation:

• set(s): converts the string into a set of unique characters.
• issubset({'0', '1'}): checks if all unique characters are either '0' or '1'.
• Efficient for strings with repeated characters as it reduces unnecessary checks.

Using Regular Expressions

Regular expressions (regex) provide a powerful and flexible way to match patterns in strings.

import re
s = "101010000111"
if re.fullmatch('[01]+', s):
    print("Yes")
else:
    print("No")

Yes

Explanation:

• [01]+ matches one or more occurrences of '0' or '1'.
• re.fullmatch(): ensures the entire string matches the pattern.
• Regex is powerful and concise but slightly slower than all() or set-based checks for simple patterns.

Using a for Loop

A simple for loop can iterate through each character of the string and manually check whether it is '0' or '1'.

s = "101010000111"
for char in s:
    if char not in '01':
        print("No")
        break
else:
    print("Yes")

Yes

Explanation:

• Iterates through each character, checking membership in '01'.
• Stops immediately when an invalid character is found using break.
• Simple to understand, but concatenation or repeated membership checks are slower than generator-based all().

Related Articles:

• Check for Binary String
• Check if two binary strings can be made equal by swapping 1s occurring before 0s