String Operators & Functions

String Operators

Much like how integers and floating point values have arithmetic operators, Strings also have built-in operators as well.

+ Operator: Concatenation

• Concatenation is the joining of two string values

* Operator: Repetition

• Repetition operator allows us to repeat a certain string multiple times

[start:end:step] Operation: Indexing and Slicing

• With indexing and slicing, we can grab different parts of a given string

in || not in Operator: Membership

• We can check if a the left operand exists or does not exist in the right operand

Examples:

# String Operation Examples

word1 = 'Hello, '
word2 = 'World!'

print('word1 + word2:', word1 + word2) # Concatenation

word3 = word1[:-2] # Slicing, resulting slice assigned to variable: word3
print('word3*3:', word3*3) # Repetition

print("'H' in word1:",'H' in word1) # Membership
print("'or' not in word2:", 'or' not in word2)

word1 + word2: Hello, World!
word3*3: HelloHelloHello
'H' in word1: True
'or' not in word2: False

Built-in Functions with Strings

Using max() and min()

• If given a single string argument, it will return a single character that has the greatest or the least ASCII value respectively

• If given multiple string arguments, they will compare each string’s characters in order and return the entire string that has the greatest or the least ASCII value respectively

Example:

# Using max() and min() on strings

print("min('HelloWorld!'):", min('HelloWorld!'))
print("max('Hello', 'Goodbye!', 'World!'):", max('Hello', 'Goodbye!', 'World!'))

min('HelloWorld!'): !
max('Hello', 'Goodbye!', 'World!'): World!

Using len()

• Given a single string parameter, it will count how many alphanumeric and special characters there are as a positive integer

Example:

# Using len() on a string

print("len('Hello, World!'):", len('Hello, World!'))
print("len(''):", len('')) # Empty String
print("len(' '):", len(' ')) # Single whitespace
print(type(''))

len('Hello, World!'): 13
len(''): 0
len(' '): 1
<class 'str'>

Basic Type & Type Conversion Related Functions str() function is used to convert a given argument into a string

• Anything from the standard python library can be converted to a string

type() function returns <class 'str'> on string values indicating that the given argument is a string value

int() function converts a numeric string to an integer

• the string argument must be able to turn into an integer

• converting a string-based decimal to an integer will result in error

• Example: int('42') is 42, int('3.14') is an error

float() function converts a decimal-like string to a floating point

• if the numeric string has no decimal point, it will add a decimal point of .0

• Example: float('3') is 3.0, float('3.14') is 3.14

bool() function converts a string to a Boolean value

• Non-empty strings are True

• An Empty string are False