# Iteration by Item (For Loops Continued)

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### Iteration by Item

Whenever we execute a loop we have gone through an iteration. We can "iterate" (or loop) through the elements within certain data types. We can loop through the following data types as they are a collection of elements.
- Strings (a collection of characters)
- Lists (a collection of elements)
- Tuples (a collection of elements)

To iterate through a collection means to look at all of the elements within the collection. We can do this using the syntax shown below.

```myList = [1,4,6,"hi"]

for item in myList:
print(item)

# This will print
1
4
6
hi
```

The variable "item" will be changed to equal the next item in the list after every loop (or iteration).

### Example

An example of when we may iterate by item is if we are checking to see if a certain item exists in a list.

```myList = [1,4,6,"hi"]

for item in myList:
if item == 6:
print("I found 6 in the list")
else:
print("This is not 6")
```

We can do the same with strings or with tuples.

```# This program counts how many "l"s appear in the string
myString = "hello tim"

count = 0
for item in myString:
if item == "l":
count += 1

print("I found", count, '"l"s in the string')

# When looping through a string we will look at each letter
# Looping through a tuple works the same as a looping through list
```