String validation

301.11 String Manipulation

String Manipulation — Note 4 of 4

Check patterns in text.

What you need to know

String methods like .isalpha(), .isdigit(), and .isalnum() check whether a string contains only certain types of characters. They return True or False.

What to know

.isalpha() — True if all letters
.isdigit() — True if all digits
.isalnum() — True if letters or digits only
Empty string returns False for all checks
Useful for input validation

Code examples

String validation

python

postcode = input("Postcode: ")
if postcode.isalnum() and len(postcode) >= 5:
    print("Valid format")
else:
    print("Invalid postcode")

← Previous noteCase conversion301.11 String Manipulation Next topic →Why subprograms301.12 Subprograms

Back to String Manipulation

Specification notes for programming are in Paper 2.

String validation

301.11 String Manipulation

Practise exam questions

String Manipulation — Note 4 of 4

Check patterns in text.

What you need to know

String methods like .isalpha(), .isdigit(), and .isalnum() check whether a string contains only certain types of characters. They return True or False.

What to know

.isalpha() — True if all letters
.isdigit() — True if all digits
.isalnum() — True if letters or digits only
Empty string returns False for all checks
Useful for input validation

Code examples

String validation

python

postcode = input("Postcode: ")
if postcode.isalnum() and len(postcode) >= 5:
    print("Valid format")
else:
    print("Invalid postcode")

← Previous noteCase conversion301.11 String Manipulation Next topic →Why subprograms301.12 Subprograms

Back to String Manipulation

Specification notes for programming are in Paper 2.