# Python | Check possible bijection between sequence of characters and digits

Given a string ‘char_seq'(sequence of characters) and a positive integer ‘dig_seq'(sequence of digits), Write a Python program to find possible bijection or one-one onto relationship between ‘char_seq’ and ‘dig_seq’ such that each character matches to one and only one digit.

Examples:

```Input : char_seq = 'bxdyxb'
dig_seq = 123421
Output : True

Input : char_seq = 'bxdyxb'
dig_seq = 123321
Output : False
```

Method #1 : Using zip method

This method simply zips the ‘char_seq’ and ‘dig_seq’ and checks if corresponding digits and characters matches or not.

 `# Python3 program to Check possible bijection  ` `# between sequence of characters and digits ` ` `  `def` `is_bijection(char_seq, dig_seq): ` `    ``z ``=` `zip``(``str``(char_seq), ``str``(dig_seq)) ` `    ``res ``=` `all``( ` `    ``(z1[``0``] ``=``=` `z2[``0``]) ``=``=` `(z1[``1``] ``=``=` `z2[``1``]) ``for` `z1 ``in` `z ``for` `z2 ``in` `z) ` `     `  `    ``return` `res ` `     `  `# Driver code ` `char_seq ``=` `'bxdyxb'` `dig_seq ``=` `123421` `print``(is_bijection(char_seq, dig_seq)) `

Output:

```True
```

Method #2 : Using itertools.groupby method

This method uses the same approach with a slight difference, it uses itertools.groupby to match characters with digits.

 `# Python3 program to Check possible bijection  ` `# between sequence of characters and digits ` `import` `itertools ` ` `  `def` `is_bijection(char_seq, dig_seq): ` `    ``z ``=` `sorted``(``zip``(``str``(char_seq), ``str``(dig_seq))) ` `    ``res ``=` `all``(gx ``=``=` `gy ` `          ``for` `k, g ``in` `itertools.groupby(z, key ``=` `lambda` `res: res[``0``]) ` `          ``for` `gx ``in` `g ``for` `gy ``in` `g) ` `     `  `    ``return` `res ` `     `  `# Driver code ` `char_seq ``=` `'bxdyxb'` `dig_seq ``=` `123421` `print``(is_bijection(char_seq, dig_seq)) `

Output:

```True
```

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