Strings

Strings

NOT mutable, change a string variable result in a new string

Need single or double quotes “” or ‘’ to enclose, for example: “Hello World” or ‘Hello World’, case sensitive

String is a sequence, iterable

s=‘abc’

s[0]=“a”

s[1]=“b”

s[2]=“c”

It is zero based indexing, index starts from zero

String can be iterated through:

for i in “abc”:
    print(i)

Convert to string, use function str()

For example:

n=12345

str(n) becomes “12345”

String is an object, meaning it has methods and attributes that can be invoked

To see all methods, type

help(<string variable>)

In Jupyter notebook, to see list of methods or attributes

Press shift key after enter <string variable>.

Strings are can be in single quote (‘) or double quotes (“)

>>> 'spam eggs' # single quotes

'spam eggs’

>>> 'doesn\'t' # use " to escape the single quote...

"doesn’t”

>>> "doesn't" # ...or use double quotes instead

"doesn’t”

>>> '"Yes," they said.'

#Use single quote to include double quote

'"Yes," they said.’

>>> "\"Yes,\" they said." #use back slash to escape quote mark

'"Yes," they said.’

#use + to concatenate 2 strings

>>>”Hello”+” World”

Hello World

Strings can be indexed (sub-scripted), with the first character having index 0. There is no separate character type; a character is simply a string of size one:

>>>Word=“Hello World”

>>>Word[0]

‘H’

>>>Word[9]

‘d’

>>>Word[-1]

#Slicing

‘d’

>>>Word[-11]

‘H’

>>>Word[0:]

‘Hello World’

>>>Word[:9]

‘Hello World’ #character at index 9 is not included.