class: big, middle

# Engineering 1020: Introduction to Programming

.title[
  .lecture[Lecture 16:]
  .title[Objects and methods]
  
  
]

.footer[[/lecture/16/](/lecture/16/)]

---

# Recall:

### Modules

* Python files as scripts **(or not)**
* The `import` statement
* Python scripts and `__main__`

???

Ask a couple of Top Hat questions here

---

# Also recall:

`dir` tells us names in a module (or other things we'll see later):

```python
>>> import example
>>> dir(example)
```

## Later is now!

---

# Other uses of `dir`

### We can use `dir()` with other things, too:

```python
dir('Hello!')
```

.floatleft[

```python
 # ...
 'isupper',
 'join',
 'ljust',
 'lower',
 # ...
 'replace',
 # ...
 'split',
 # ...
```

]

## Q: what are these?

## A: object _methods_

## Q: what are objects?

---

# Object

## A bundle of _code_ and _data_

### Example: string

**Code:** things we can do with _any_ string
--
 — _methods_

> find the first J in a string

> count the spaces in a string

> convert a string to upper-case characters

**Data:** the characters in _this_ string

---

# Methods

### Like functions, but for _specific_ objects

```python
# Get the length of the temperatures list:
l = len(temperatures)

# Count the "Jo"'s in the instructor's name:
jos = instructor_name.count('Jo')
```

### A method knows _which object_ it's applied to

```python
'hello'.count('l')
'Listen Lionel, Ligon likes leprechauns but Lisa loves lions'.count('l')
```

???

Same code, different object

---

# A brief foretaste

```python
import matplotlib.pyplot as plt

f = plt.figure()
ax = plt.axes()

independent = [1, 2, 3, 4]
dependent = [10, 100, 275, 325]

ax.plot(independent, dependent)
ax.set_xlabel('x')
ax.set_ylabel('y')

f.show()
```

---

# A brief foretaste

```python
import matplotlib.pyplot as plt

f = plt.figure()
ax = plt.axes()

independent = [1, 2, 3, 4]
dependent = [10, 100, 275, 325]

ax.plot(independent, dependent)
ax.set_xlabel('x')
ax.set_ylabel('y')

f.show()
```

---

# List methods

### Some commonly-used methods on lists:

.floatleft[
* `append`
* `clear`
* `count`
* `extend`
]

.floatleft[
* `index`
* `insert`
* `remove`
* `reverse`
]

.floatleft[
* `sort`
]

# and more!

---

# String methods

.floatleft[
* capitalize
* count
* endswith
* find
* index
* isalnum
]

.floatleft[
* isalpha
* isascii
* isdecimal
* isdigit
* isidentifier
* islower
]

.floatleft[
* isnumeric
* isprintable
* isspace
* istitle
* isupper
* join
]

.floatleft[
* lower
* lstrip
* replace
* rfind
* split
]

### and more!

---

# So...

### What do I have to remember?

* what each of these methods do (clue's often in the name)
--

* _not_ a list of all of these methods

**On an exam:**
I'll remind you of what methods _exist_, you'll remember what they _do_

**On an assignment / in your project:**
practice using whichever methods are helpful!

---

# Summary

### Objects

### Methods

### Common methods of:

* `list`
* `str`

---
class: big, middle

(here endeth the lesson)