Python – strings, string concatenation and repetition

To assign a string to a variable, enclose the test either in apostrophes ‘…’ or in double quotes “…”:

string=’I am a cat’

string=”I am a cat”

If the string contains an apostrophe (I’m), then the entire string must be enclosed in double quotes, and vice versa. If the string contains both an apostrophe and double quotes, then a backslash must be used to escape the characters.

Indexing in rows

In any string, any character can be accessed using the command: string[0], where the number inside the square brackets indicates the position of the character. The last character of any string is denoted as string[-1]. This is called indexing.

name=’veronica’

print(name[-1])

a #this is the result

If we want to access part of the string, then we write the interval in square brackets:

  • name[2:5] – from the second to the fifth characters;
  • name[:5] – from the beginning of the line to the fifth character;
  • name[5:] – from the fifth to the end of the line.

String concatenation (addition)

print(‘con’+’catenation’) – addition without spaces if all arguments are strings;

print(‘con’,’catenation’) – addition with spaces, not necessarily just strings;

print(‘con’+’catenation’,5) – combined addition.

Repeating lines

print(2*(‘con’+’catenation’)) – repeat twice without spaces

An example of using string concatenation and indexing:

name=’Vera’

name=’L’+name[1:]

print(name)

Lera #result