The for and while Statements
The General Form of for
We previously studied
strings and
lists, and now it is time to navigate through their elements. We will use
for, which has the
general form as shown below:
for variable in data_collection:
subordinate_instructions
We can read it as:
for each element in the collection, held by variable, perform a set of subordinate processing instructions.
Note. Strings are not collections of data, but they can be iterated with
for.
EXAMPLES
Below, we display
in turn all the elements of a list and then all the characters of a string:
DETAILS
In the first case, the
print statement within the
for loop was executed
5 times,
once for each element of the list:
|
Run the simulation
|
At each step, the variable
x is assigned the next element to be used within the set of instructions.
The string
str_1 has a length of
17, so the
for loop was repeated
that many times...
NOTE
The data types
str and
list are
iterable.
For example, the type
int is not iterable, so we cannot use
for to access its digits,
because they are not elements -
it is stored in memory as a numeric value:
Proceed to the next page.
