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# Python: Check if every consecutive sequence of zeroes is followed by a consecutive sequence of ones of same length

## Python Basic - 1: Exercise-142 with Solution

Write a Python program to check if every consecutive sequence of zeroes is followed by a consecutive sequence of ones of the same length in a given string. Return True/False.

Sample Solution:

Python Code:

``````# Import the 're' module for regular expressions.
import re

# Define a function 'test' that checks if every consecutive sequence of zeroes is followed by a consecutive sequence of ones.
def test(txt):
# Use regular expressions to find all consecutive sequences of zeroes and ones and compare their lengths.
return [len(i) for i in re.findall('0+', txt)] == [len(i) for i in re.findall('1+', txt)]

# Test the function with different input sequences.
str1 = "001011"
print("\nOriginal sequence:", str1)
print("Check if every consecutive sequence of zeroes is followed by a consecutive sequence of ones in the said string:")
print(test(str1))

str1 = "01010101"
print("\nOriginal sequence:", str1)
print("Check if every consecutive sequence of zeroes is followed by a consecutive sequence of ones in the said string:")
print(test(str1))

str1 = "00"
print("\nOriginal sequence:", str1)
print("Check if every consecutive sequence of zeroes is followed by a consecutive sequence of ones in the said string:")
print(test(str1))

str1 = "000111000111"
print("\nOriginal sequence:", str1)
print("Check if every consecutive sequence of zeroes is followed by a consecutive sequence of ones in the said string:")
print(test(str1))

str1 = "00011100011"
print("\nOriginal sequence:", str1)
print("Check if every consecutive sequence of zeroes is followed by a consecutive sequence of ones in the said string:")
print(test(str1))

str1 = "0011101"
print("\nOriginal sequence:", str1)
print("Check if every consecutive sequence of zeroes is followed by a consecutive sequence of ones in the said string:")
print(test(str1))
``````

Sample Output:

```Original sequence: 001011
Check if every consecutive sequence of zeroes is followed by a consecutive sequence of ones in the said string:
False

Original sequence: 01010101
Check if every consecutive sequence of zeroes is followed by a consecutive sequence of ones in the said string:
True

Original sequence: 00
Check if every consecutive sequence of zeroes is followed by a consecutive sequence of ones in the said string:
False

Original sequence: 000111000111
Check if every consecutive sequence of zeroes is followed by a consecutive sequence of ones in the said string:
True

Original sequence: 00011100011
Check if every consecutive sequence of zeroes is followed by a consecutive sequence of ones in the said string:
False

Original sequence: 0011101
Check if every consecutive sequence of zeroes is followed by a consecutive sequence of ones in the said string:
False
```

Explanation:

Here is a breakdown of the above Python code:

• Importing the 're' module:
• Import the "re" module for regular expressions.
• Define the 'test' function:
• Define a function "test()" that checks if every consecutive sequence of zeroes is followed by a consecutive sequence of ones.
• Regular expression matching:
• Use regular expressions to find all consecutive sequences of zeroes ('0+') and ones ('1+') in the input string.
• Comparing lengths:
• Compares the lengths of consecutive sequences of zeroes and ones to check the specified condition.

Flowchart:

Python Code Editor:

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