Skip to content
Snippets Groups Projects
Commit d7b9d411 authored by Cole Nelson's avatar Cole Nelson
Browse files

updt w/ dict comph

parent 1dd16bc6
No related branches found
No related tags found
No related merge requests found
Hide whitespace changes
Inline Side-by-side
f23/Cole_Lecture_Notes/26_Files_and_Directories/Lec26_Files_and_Directories_Solution_Nelson.ipynb
+ 12
− 2
View file @ d7b9d411
%% Cell type:code id: tags:
``` python
# Warmup 0a: Run these!
import os
from collections import namedtuple
```
%% Cell type:code id: tags:
``` python
# Warmup 0b:
# Give an example of a mutable object... list
# Give an example of an immutable object... tuple
```
%% Cell type:code id: tags:
``` python
# Warmup 1: Create a type Fruit that has 3 attributes (use namedtuple)
# - name
# - num_seeds
# - juicyness
Fruit = namedtuple("Fruit", ['name', 'num_seeds', 'juicyness'])
```
%% Cell type:code id: tags:
``` python
# Warmup 2: Add three fruits to the list. You choose!
# - name should be a string
# - num_seeds should be an int
# - juicyness should be a float between [0.0, 100.0]
fruits = [
Fruit("Apple", 20, 25.0),
Fruit("Pineapple", 0, 75.0),
Fruit("Strawberry", 100, 45.0)
]
```
%% Cell type:code id: tags:
``` python
# Warmup 3: Sort fruits based on juicyness
fruits.sort(key=lambda f:f.juicyness)
fruits
```
%% Cell type:code id: tags:
``` python
# Warmup 4: Create a list of fruits that have >10 seeds.
[f for f in fruits if f.num_seeds > 10]
```
%% Cell type:code id: tags:
``` python
# Warmup 5: Same thing as above, but just the names of the fruit.
[f.name for f in fruits if f.num_seeds > 10]
```
%% Cell type:code id: tags:
``` python
# Warmup 6: Same thing as above, but if it has juicyness > 33, display it in uppercase.
[f.name.upper() if f.juicyness > 33 else f.name for f in fruits if f.num_seeds > 10]
```
%% Cell type:code id: tags:
``` python
# Warmup 7: Can you change the name of a fruit?
# Warmup 7: Create a dictionary mapping each fruit's name to its total # of seeds
{f.name: f.num_seeds for f in fruits}
```
%% Cell type:code id: tags:
``` python
# Warmup 8: Can you change the name of a fruit?
# No, namedtuples are immutable.
fruits[0].name = "fail"
```
%% Cell type:code id: tags:
``` python
# Warmup 8: Catch any errors the user may make.
# Warmup 9: Catch any errors the user may make.
user_fruits = []
while(True):
print("Current fruits", user_fruits)
try:
fruit_name = input("Enter a name for the fruit... ")
fruit_seeds = int(input("Enter a num_seeds for the fruit... "))
fruit_juicy = float(input("Enter a juicyness for the fruit... "))
user_fruits.append(Fruit(fruit_name, fruit_seeds, fruit_juicy))
except Exception as e:
print("Name must be a str, num_seeds must be an int, and juicyness must be a float!")
print(type(e))
```
%% Cell type:markdown id: tags:
## Lecture 26: Files and Directories
**Learning Objectives:**
- Use built-in functions with files:
- open
- close
- read
- write
- Use file-specific os module functions:
- os.listdir
- os.mkdir
- os.path.exists
- os.path.isfile
- os.path.isdir
- os.path.join
- Use try/except blocks or a with statement to handle errors that may occur when using files
This content will be on Wednesday's exam!
%% Cell type:markdown id: tags:
### Use built-in functions with files: open, close, read, write
%% Cell type:code id: tags:
``` python
# example 1a: let's learn how to write to a file
# open a file, give it a name, prepare it for writing
file_obj = open("debug_tips.txt", "w")
# Add this content:
# Debug Tips:
# 1. Write the least amount of code you can test
# 2. Don't try to write the complete solution at first
# 3. Assume from the start that things will go wrong
# 4. Always know the state of your program (print out vital information)
# use the write command to write a string to the file
file_obj.write("Debug Tips:\n")
file_obj.write("1. Write the least amount of code you can test\n")
# TODO Complete the rest!
file_obj.write("2. Don't try to write the complete solution at first\n")
file_obj.write("3. Assume from the start that things will go wrong\n")
file_obj.write("4. Always know the state of your program (print out vital information)\n")
# you MUST close the file for the changes to actual be stored in the file
file_obj.close()
```
%% Cell type:code id: tags:
``` python
# Next: Let's write 10 random ints (from 1 to 5) to a file
import random
path = "nums.txt"
fo = open(path, "w")
for i in range(10):
fo.write(str(random.randint(1,5)) + "\n")
fo.close()
```
%% Cell type:code id: tags:
``` python
# Now: Let's OVERWRITE THE FILE by writing 10K random ints (from 1 to 10) to a file
import random
path = "nums.txt"
fo = open(path, "w")
for i in range(10000):
fo.write(str(random.randint(1,10)) + "\n")
fo.close()
```
%% Cell type:code id: tags:
``` python
# Think Back: What if we want to write one more debugging tip?
file_obj = open("debug_tips.txt", "w")
file_obj.write("5. Writing a program is not a linear path; there will be ups and downs!\n")
file_obj.close()
# We'll come back to this!
```
%% Cell type:markdown id: tags:
### Reading Files
%% Cell type:markdown id: tags:
![Screen%20Shot%202021-11-08%20at%208.30.02%20AM.png](attachment:Screen%20Shot%202021-11-08%20at%208.30.02%20AM.png)
%% Cell type:code id: tags:
``` python
path = "debug_tips.txt"
# create a file object but open for READING
f_obj = open(path, 'r') # "r" is optional
data = f_obj.read()
print(data)
f_obj.close()
```
%% Cell type:code id: tags:
``` python
# TODO Add the fifth debugging tip, but do not
# overwrite what's currently in the file!
# Read in the previous text..
path = "debug_tips.txt"
f_obj = open(path, 'r') # "r" is optional
data = f_obj.read()
f_obj.close()
file_obj = open(path, "w")
# ... and add it on to the new.
file_obj.write(data)
file_obj.write("5. Writing a program is not a linear path; there will be ups and downs!\n")
file_obj.close()
```
%% Cell type:code id: tags:
``` python
# or... open the file in "append" mode.
file_obj = open("debug_tips.txt", "a")
file_obj.write("5. Writing a program is not a linear path; there will be ups and downs!\n")
file_obj.close()
```
%% Cell type:code id: tags:
``` python
# alternative way to read: as a list
file_obj = open("debug_tips.txt", "r")
my_data = list(file_obj)
print(my_data)
file_obj.close()
```
%% Cell type:code id: tags:
``` python
# TODO: Sum all the numbers in nums.txt!
path = "nums.txt"
f_obj = open(path, 'r') # "r" is optional
lines = list(f_obj)
nums = []
for line in lines:
actualNum = int(line.strip())
nums.append(actualNum)
sum(nums)
```
%% Cell type:markdown id: tags:
### Use these file-specific os module functions:
- os.listdir
- os.mkdir
- os.path.exists
- os.path.isfile
- os.path.isdir
- os.path.join
%% Cell type:code id: tags:
``` python
os.listdir(".") # creates a list from the contents of a directory
```
%% Cell type:code id: tags:
``` python
# Make a directory...
# Similar to mkdir command in PowerShell.
# Note if you run the same command twice,
# the 2nd time you will get an error. Why?
os.mkdir("coles folder")
os.listdir(".")
```
%% Cell type:code id: tags:
``` python
# os.path is a sub-module of os .... does not need importing again
print(os.path.exists("coles folder")) # does this file/folder (at this path) exist?
print(os.path.isfile("coles folder")) # nope
print(os.path.isdir("coles folder")) # yep
```
%% Cell type:code id: tags:
``` python
# This function is like the list join method, which combines things into a string,
# but it automatically senses which OS you are using and joins them with either a \ or /
path = os.path.join("my_folder","file1.txt")
print(path) # what do you get?
```
%% Cell type:markdown id: tags:
**There are lots of things that can go wrong when reading or writing files**
- file does not exist
- you don't have write permission
- not enough space on the drive to write out the entire file
- use a directory name in place file name (or vice versa)
- and more....
%% Cell type:code id: tags:
``` python
# let's figure out how to handle a command to open a file that does not exist
path = input("enter the name of the file to open:")
try:
file_object = open(path, "r") # "r" is for reading, but is the default
d = file_object.read()
print(d)
file_object.close()
except FileNotFoundError as e:
print(type(e))
print(path, "could not be opened")
# Does this cover all exceptions? What else could go wrong?
# What does this mean for opening and closing a file?
```
%% Cell type:markdown id: tags:
**Python is all about shortening code. Is there a way to shorten the process of:**
- opening a file
- handling any Errors while reading/writing
- closing the file
%% Cell type:code id: tags:
``` python
# we can use a 'with' statement to shorten our code
import random
with open("some_numbers.txt", "w") as f:
for i in range(10):
f.write(str(random.randint(1,100)) + "\n")
# don't need to close, even if there's an error!
```
%% Cell type:code id: tags:
``` python
# Take a look at your file organizer to find the file some_numbers.txt
```
%% Cell type:markdown id: tags:
**Case Studies: Mostly finished, larger programs**
Goal: Run the program, read the code, make small changes
%% Cell type:code id: tags:
``` python
# Case Study: score tracker
# remember: a JSON file is structured like a Python dictionary
# so its easy to convert back and forth
# JSONDecodeError when there is issues with the json file
import json # to read/write a JSON file
import os # to see if score file exists
def read_json(path):
with open(path, encoding="utf-8") as f:
return json.load(f) # dict, list, etc
# data is a dict, list, etc
def write_json(path, data):
with open(path, 'w', encoding="utf-8") as f:
json.dump(data, f, indent=2)
def add_point(player_name, file_name):
scores = {}
# TOOD: Check if "point.json" exists, if so load data from it
if os.path.exists(file_name):
scores = read_json(file_name)
# TODO: Check if player is a known player
if player_name in scores:
scores[player_name] += 1
else:
scores[player_name] = 1
else:
scores[player_name] = 1
write_json(file_name, scores)
# TODO: print out each person's score
print(scores)
```
%% Cell type:code id: tags:
``` python
# You can try this yourself... different name, different file
# Then, go back to your Jupyter Notebook directory and open the file you made
```
%% Cell type:code id: tags:
``` python
add_point("Cole", "points.json")
```
%% Cell type:code id: tags:
``` python
# Case Study: Recursive File Searcher
# In an earlier lecture, we wrote a function that recursively searches a list of lists
# this program takes that idea and applies it to files and directories.
# To understand this program, you might want to first see what directories you have.
# TODO: Try exploring your computer with os.listdir
os.listdir("..")
```
%% Cell type:code id: tags:
``` python
# program recursive file searcher
import os
def recursive_dir_search(searchDirectory, searchFileName):
for curr in os.listdir(searchDirectory):
# build a path to this current thing
curr = os.path.join(searchDirectory, curr)
#check if curr is a file
if os.path.isfile(curr):
#check if it contains the search name
if searchFileName in curr: # base case...no recursive call
f = open(curr)
contents = f.read(50) # reads first 50 chars into a string
f.close()
return contents
else: # recursive case!!
contents = recursive_dir_search(curr, searchFileName)
if contents != None: # we found something
return contents
# finished all recursive searching and never found it
return None
# this function is like our main program
def dir_search(dir_name, file_name):
if not os.path.exists(dir_name):
print("Unable to find searchDirectory!")
else:
contents = recursive_dir_search(dir_name, file_name)
# TODO: Display the results of our recursive search.
if contents == None:
print(file_name, "not found")
else:
print(contents)
```
%% Cell type:code id: tags:
``` python
dir_search("..", "project.py")
```
%% Cell type:markdown id: tags:
![image.png](attachment:image.png)
%% Cell type:markdown id: tags:
![image.png](attachment:image.png)
......
f23/Cole_Lecture_Notes/26_Files_and_Directories/Lec26_Files_and_Directories_Template_Nelson.ipynb
+ 11
− 2
View file @ d7b9d411
%% Cell type:code id: tags:
``` python
# Warmup 0a: Run these!
import os
from collections import namedtuple
```
%% Cell type:code id: tags:
``` python
# Warmup 0b:
# Give an example of a mutable object...
# Give an example of an immutable object...
```
%% Cell type:code id: tags:
``` python
# Warmup 1: Create a type Fruit that has 3 attributes (use namedtuple)
# - name
# - num_seeds
# - juicyness
```
%% Cell type:code id: tags:
``` python
# Warmup 2: Add three fruits to the list. You choose!
# - name should be a string
# - num_seeds should be an int
# - juicyness should be a float between [0.0, 100.0]
fruits = [
]
```
%% Cell type:code id: tags:
``` python
# Warmup 3: Sort fruits based on juicyness
```
%% Cell type:code id: tags:
``` python
# Warmup 4: Create a list of fruits that have >10 seeds.
```
%% Cell type:code id: tags:
``` python
# Warmup 5: Same thing as above, but just the names of the fruit.
```
%% Cell type:code id: tags:
``` python
# Warmup 6: Same thing as above, but if it has juicyness > 33, display it in uppercase.
```
%% Cell type:code id: tags:
``` python
# Warmup 7: Can you change the name of a fruit?
# Warmup 7: Create a dictionary mapping each fruit's name to its total # of seeds
```
%% Cell type:code id: tags:
``` python
# Warmup 8: Catch any errors the user may make.
# Warmup 8: Can you change the name of a fruit?
```
%% Cell type:code id: tags:
``` python
# Warmup 9: Catch any errors the user may make.
user_fruits = []
while(True):
print("Current fruits", user_fruits)
fruit_name = input("Enter a name for the fruit... ")
fruit_seeds = int(input("Enter a num_seeds for the fruit... "))
fruit_juicy = float(input("Enter a juicyness for the fruit... "))
user_fruits.append(Fruit(fruit_name, fruit_seeds, fruit_juicy))
```
%% Cell type:markdown id: tags:
## Lecture 26: Files and Directories
**Learning Objectives:**
- Use built-in functions with files:
- open
- close
- read
- write
- Use file-specific os module functions:
- os.listdir
- os.mkdir
- os.path.exists
- os.path.isfile
- os.path.isdir
- os.path.join
- Use try/except blocks or a with statement to handle errors that may occur when using files
This content could be on Wednesday's exam!
%% Cell type:markdown id: tags:
### Use built-in functions with files: open, close, read, write
%% Cell type:code id: tags:
``` python
# example 1a: let's learn how to write to a file
# open a file, give it a name, prepare it for writing
file_obj = open("debug_tips.txt", "w")
# Add this content:
# Debug Tips:
# 1. Write the least amount of code you can test
# 2. Don't try to write the complete solution at first
# 3. Assume from the start that things will go wrong
# 4. Always know the state of your program (print out vital information)
# use the write command to write a string to the file
file_obj.write("Debug Tips:\n")
file_obj.write("1. Write the least amount of code you can test\n")
# TODO Complete the rest!
# you MUST close the file for the changes to actual be stored in the file
file_obj.close()
```
%% Cell type:code id: tags:
``` python
# Next: Let's write 10 random ints (from 1 to 5) to a file
import random
path = "nums.txt"
fo = open(path, "w")
for i in range(10):
fo.write(str(random.randint(1,5)) + "\n")
fo.close()
```
%% Cell type:code id: tags:
``` python
# Now: Let's OVERWRITE THE FILE by writing 10K random ints (from 1 to 10) to a file
import random
path = "nums.txt"
fo = open(path, "w")
for i in range(10000):
fo.write(str(random.randint(1,10)) + "\n")
fo.close()
```
%% Cell type:code id: tags:
``` python
# Think Back: What if we want to write one more debugging tip?
file_obj = open("debug_tips.txt", "w")
file_obj.write("5. Writing a program is not a linear path; there will be ups and downs!\n")
file_obj.close()
# We'll come back to this!
```
%% Cell type:markdown id: tags:
### Reading Files
%% Cell type:markdown id: tags:
![Screen%20Shot%202021-11-08%20at%208.30.02%20AM.png](attachment:Screen%20Shot%202021-11-08%20at%208.30.02%20AM.png)
%% Cell type:code id: tags:
``` python
path = "debug_tips.txt"
# create a file object but open for READING
f_obj = open(path, 'r') # "r" is optional
data = f_obj.read()
print(data)
f_obj.close()
```
%% Cell type:code id: tags:
``` python
# TODO Add the fifth debugging tip, but do not
# overwrite what's currently in the file!
```
%% Cell type:code id: tags:
``` python
# alternative way to read: as a list
file_obj = open("debug_tips.txt", "r")
my_data = list(file_obj)
print(my_data)
file_obj.close()
```
%% Cell type:code id: tags:
``` python
# TODO: Sum all the numbers in nums.txt!
```
%% Cell type:markdown id: tags:
### Use these file-specific os module functions:
- os.listdir
- os.mkdir
- os.path.exists
- os.path.isfile
- os.path.isdir
- os.path.join
%% Cell type:code id: tags:
``` python
os.listdir(".") # creates a list from the contents of a directory
```
%% Cell type:code id: tags:
``` python
# Make a directory...
# Similar to mkdir command in PowerShell.
# Note if you run the same command twice,
# the 2nd time you will get an error. Why?
```
%% Cell type:code id: tags:
``` python
# os.path is a sub-module of os .... does not need importing again
print(os.path.exists("my new folder")) # does this file/folder (at this path) exist?
print(os.path.isfile("my new folder")) # nope
print(os.path.isdir("my new folder")) # yep
```
%% Cell type:code id: tags:
``` python
# This function is like the list join method, which combines things into a string,
# but it automatically senses which OS you are using and joins them with either a \ or /
path = os.path.join("my_folder","file1.txt")
print(path) # what do you get?
```
%% Cell type:markdown id: tags:
**There are lots of things that can go wrong when reading or writing files**
- file does not exist
- you don't have write permission
- not enough space on the drive to write out the entire file
- use a directory name in place file name (or vice versa)
- and more....
%% Cell type:code id: tags:
``` python
# let's figure out how to handle a command to open a file that does not exist
path = input("enter the name of the file to open:")
file_object = open(path, "r") # "r" is for reading, but is the default
d = file_object.read()
print(d)
file_object.close()
# Does this cover all exceptions? What else could go wrong?
# What does this mean for opening and closing a file?
```
%% Cell type:markdown id: tags:
**Python is all about shortening code. Is there a way to shorten the process of:**
- opening a file
- handling any Errors while reading/writing
- closing the file
%% Cell type:code id: tags:
``` python
# we can use a 'with' statement to shorten our code
import random
with open("some_numbers.txt", "w") as f:
for i in range(10):
f.write(str(random.randint(1,100)) + "\n")
# don't need to close, even if there's an error!
```
%% Cell type:code id: tags:
``` python
# Take a look at your file organizer to find the file some_numbers.txt
```
%% Cell type:markdown id: tags:
**Case Studies: Mostly finished, larger programs**
Goal: Run the program, read the code, make small changes
%% Cell type:code id: tags:
``` python
# Case Study: score tracker
# remember: a JSON file is structured like a Python dictionary
# so its easy to convert back and forth
# JSONDecodeError when there is issues with the json file
import json # to read/write a JSON file
import os # to see if score file exists
def read_json(path):
with open(path, encoding="utf-8") as f:
return json.load(f) # dict, list, etc
# data is a dict, list, etc
def write_json(path, data):
with open(path, 'w', encoding="utf-8") as f:
json.dump(data, f, indent=2)
def add_point(player_name, file_name):
scores = {}
# TOOD: Check if "point.json" exists, if so load data from it
if ???:
scores = read_json(file_name)
# TODO: Check if player is a known player
if ???:
scores[player_name] += 1
else:
scores[player_name] = 1
else:
scores[player_name] = 1
write_json(file_name, scores)
# TODO: print out each person's score
???
```
%% Cell type:code id: tags:
``` python
# You can try this yourself... different name, different file
# Then, go back to your Jupyter Notebook directory and open the file you made
```
%% Cell type:code id: tags:
``` python
add_point("Rachel", "points.json")
```
%% Cell type:code id: tags:
``` python
# Case Study: Recursive File Searcher
# In an earlier lecture, we wrote a function that recursively searches a list of lists
# this program takes that idea and applies it to files and directories.
# To understand this program, you might want to first see what directories you have.
# TODO: Try exploring your computer with os.listdir
os.listdir("..")
```
%% Cell type:code id: tags:
``` python
# program recursive file searcher
import os
def recursive_dir_search(searchDirectory, searchFileName):
for curr in os.listdir(searchDirectory):
# build a path to this current thing
curr = os.path.join(searchDirectory, curr)
# TODO check if curr is a file
if ???:
#check if it contains the search name
if searchFileName in curr: # base case...no recursive call
f = open(curr)
contents = f.read(50) # reads first 50 chars into a string
f.close()
return contents
else: # recursive case!!
contents = recursive_dir_search(curr, searchFileName)
if contents != None: # we found something
return contents
# finished all recursive searching and never found it
return None
# this function is like our main program
def dir_search(dir_name, file_name):
if not os.path.exists(dir_name):
print("Unable to find searchDirectory!")
else:
contents = recursive_dir_search(dir_name, file_name)
# TODO: Display the results of our recursive search.
???
```
%% Cell type:code id: tags:
``` python
dir_search("..", "project.py")
```
%% Cell type:markdown id: tags:
![image.png](attachment:image.png)
%% Cell type:markdown id: tags:
![image.png](attachment:image.png)
......
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment