Character strings

Strings are delimited with single ' or double " or triple-double """ inverted commas. The latter variant allows multi-line strings to be written:

Example

"Hello world"
'Hello world'
""" Hello
dear
world"""

A mixture of inverted commas for separation is not permitted, but their occurrence in a text separated by other inverted commas is:

Example

"Can't touch this"
'Then he said "Heureka!".'

However, if both characters ' and " are to occur, then the occurrences of the outer inverted commas in the string itself must be masked by prefixing them with \:

Example

'Then he said "Can\'t touch this".'

Two strings can be combined:

Example

"Whoever says A " + "can be wrong." # "Whoever says A can be wrong."

With a defined addition, a multiplication is of course also defined:

Example

"Na" * 12 + " Batman!" # 'NaNaNaNaNaNaNaNaNaNaNaNa Batman!'

If you have a list of strings, you can join them using the str.join function:

Example

",".join(["Monday", "Tuesday"]) # 'Monday,Tuesday'
"-...-".join(["Monday", "Tuesday", "Wednesday"]) # 'Monday-...-Tuesday-...-Wednesday'

Parts of a string can be obtained via the indexing [a:b]. Here, a is the first character to be extracted and b is the first character that should no longer be included. In Python, the count starts at 0.

Example

"Testator"[2:6] # 'stat'

Individual letters can also be extracted in this way, negative indices count from the back:

Example

"Part"[0] # 'P'
"Part"[-1] # 't'
"Part"[-3:-1] # 'ar'

If one of the limits in [a:b] is omitted, 0 is assumed for a and -1 for b. This is a general convention in Python beyond strings.

Example

"Part"[1:] # 'art'
"Part"[-1] # 't'
"Part"[:-2] # 'Pa'

Conversion

Conversion is simple but not always obvious:

Example

str(2) # '2'
str(1/9*9) # '1.0', because 1/9 was evaluated as a decimal number
str(1) # '1'
str(1/9) # '0.1111111111111111'