String Boolean Tests

Control structures form a large part of any workflow, and having a good understanding of the boolean checks that we can perform on strings is essential for data wrangling prior to analysis.

Case Checks

isupper() returns True if all characters in the string are uppercase.

'HELLO'.isupper()

True

'Hello'.isupper()

False

islower() returns True if all characters in the string are lowercase.

'hello'.islower()

True

'Hello'.islower()

False

istitle() returns True if all starting characters in the string are capitalised.

'Hello World'.istitle()

True

'hello world'.istitle()

False

Start and End Checks

Do note that Python is a case-sensitive language, as you can see from the following examples.

'Hello'.startswith('H')

True

'Hello'.startswith('h')

False

'Hello'.endswith('o')

True

'Hello'.endswith('O')

False

Type Checks

isalnum() checks if all characters in the string are alphanumeric.

'abc123'.isalnum()

True

'abc123!'.isalnum()

False

isalpha() checks if all characters in the string are alphabets.

'abc123'.isalpha()

False

'abc'.isalpha()

True

isdigit() checks if all characters in the string are numbers.

'123'.isdigit()

True

'123a'.isdigit()

False

isspace() checks if all characters in the string are spaces.

'  '.isspace()

True

' a '.isspace()

False