This chapter introduced a lot of new ideas. The following summary 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 to 5
.
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 to ana
(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 to True
. 'Zeta' < 'Appricot'
evaluates to False
.'Zebra' <= 'aardvark'
evaluates to True
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 to True
.'cheese' in "I'll be checking for you."
evaluates to False
.