9. Summary¶
This chapter introduced a lot of new ideas. The following summary includes some of these and may prove helpful in remembering what you learned.
- indexing (
[]
) - Access a single character in a string using its position (starting from 0). Example:
'This'[2]
evaluates to'i'
. - length function (
len
) - Returns the number of characters in a string. Example:
len('happy')
evaluates to5
. - for loop traversal (
for
) Traversing a string means accessing each character in the string, one at a time. For example, the following for loop:
for ix in 'Example': ...
executes the body of the loop 7 times with different values of ix each time.
- slicing (
[:]
) - A slice is a substring of a string. Example:
'bananas and cream'[3:6]
evaluates toana
(so does'bananas and cream'[1:4]
). - string comparison (
>, <, >=, <=, ==, !=
) - The six common comparision operators work with strings, evaluating according to lexigraphical order. Examples:
'apple' < 'banana'
evaluates toTrue
.'Zeta' < 'Appricot'
evaluates toFalse
.'Zebra' <= 'aardvark'
evaluates toTrue
because all upper case letters precede lower case letters. - in and not in operator (
in
,not in
) - The
in
operator tests whether one string is contained inside another string. Examples:'heck' in "I'll be checking for you."
evaluates toTrue
.'cheese' in "I'll be checking for you."
evaluates toFalse
.