Python Flashcards
What is an IDE?
Integrated Development Environment. You can use any text editor to write code. However, most integrated development environments (IDEs) include functionality that goes beyond text editing. They provide a central interface for common developer tools, making the software development process much more efficient. Developers can start programming new applications quickly instead of manually integrating and configuring different software.
What are variables and how do you define them?
Variables are containers for storing data values. Separate space between words with underscore(“_”). Structured: variable_name = variable_value. Basically similar to JavaScript, but without variable declaration keywords like var, const, and let.
What are some of the data types in Python?
Strings, numbers, boolean, tuples
What are strings?
Text encapsulated within quotes(“”). Use \n to start a new line within a quote. Use " to print a quotation mark within a string. You can use string functions (len, index, upper, lower…etc)
What is concatnation?
Joining two or more string together.
What are some number functions?
str(): convert number to string. Used to concatenate string with numbers.
abs(): convert number to an absolute value.
pow(): pass two parameters, takes the power of the second parameter to the first one.
max(): get the max number from the parameters.
min(): get the min number from the parameters.
round(): round the number
How can you import other number functions?
from math import *. Import from the math module.
How to get input from user?
using input().
ex: name = input(“Enter your name: “)
age = input(“Enter your age: “)
print(“Hello “ + name + “! You are “ + age)
What is the default data type when getting input from user?
string. If you want to work with numbers, you need to convert user input into number. ex: int(), float()
What are lists? How do you define them?
a set of data.
ex: friends = [“Kevin”, “Karen”, “Jim”]
How do you access the last item on the list?
list[-1]
How do you access all of the list items after index 1?
list[1:]
How do you access second and third item on the list?
list[1:3]. The last number does not get included on the result
What are some of the List Functions?
extend(): allows you to add another list to a list.
append(): allows you to add an item to the end of the list.
insert(): allows you to add in a specific index. takes two parameters (index_number, “add_item”)
remove(): allows you to remove an item from the list
clear(): removes every element from the list
pop(): removes last element from the list
count(): gives you the number of times the element occurred in the list
index(): gives you the index number in the list where the element appears
sort(): sorts the list in ascending order
reverse(): reverse the list items
copy(): copy the list
What is a tuple?
similar to lists but wrap elements in () and tuples are immutable. you can make a list of tuples
How to create functions? How do you call functions?
def function_name():
function_name()
What is if statement?
evaluates a condition. If evaluated True, the code inside the body of it is executed. If not, the code inside the body of if is skipped.
what is get in python?
allows you to access values by accessing the key. You can also put in default action if the key is not found.
What is a while loop in python? What is the syntax?
allows you to execute a block of code multiple times. until the condition becomes false.
i = 1
while i <= 10:
print(i)
i += 1
print(“Done with loop”)
What is a for loop in python? What is the syntax?
used for iterating over a sequence.
for letter in “Giraffe Academy”:
print(letter)
What are 2D lists?
lists within a list.
How do you write comments? What are they?
start a line with #. For multiple lines, write comment in between ‘'’comment’’’. Does not get recognized when running program. Also to comment out code.
What are try and except blocks?
Used for error catching. Allows your program to run smoothly even when errors occurr. Always want to be specific when catching errors.
What is the syntax for try and except?
try:
answer = 10/0
number = int(input(“Enter a number: “))
print(number)
except ZeroDivisionError as err:
print(err)
except ValueError:
print(“Invalid Input”)
How do you open external files? What are some examples of mode?
open(“file_name”, “mode”).
“a”: append, means append information to end of file
“r+”: read and write
“r”: read
What are some rules to keep in mind when reading files?
always want to check if file is readable (use readable function). always want to close file after open (use the close function). Appending you need to be careful because you can mess up the file. If you want to add on a new line, you need to add \n at the beginning. “w” mode overwrites the entire file.
What is a module?
Python file that you can import into current python file.
How do you install packages in python?
pip install packageName
What are classes and objects in python?
Allows you to create your own data types. Class defines what a data type is. Object is the actual data. You can model real world entities and create a data type of it.
What are class functions in python?
functions that can be used on the objects of the class
What is inheritance in python?
allows you to inherit properties from Class to different Class
What is python interpreter?
Environment you can use to run python commands. For example, you can run python commands in the terminal.
What are docstrings?
similar to # for commenting out code, but allows you to put in multiple lines. prints when using help()
How do you define default values when defining a function?
def greet(who=”Colin”):
print(“Hello,”, who)
who variable can be used
What are higher order functions?
functions that operate on other functions
What does list[:3] mean?
get the list starting from index 0 and continuing up to but not including index 3.
What does list[3:] mean?
get the list starting from index 3 and continuing up to end of list.
What does list[1:-1] mean?
get all the list except first and last
What does list[-3:] mean?
get the last 3
What is list comprehension?
What is pandas in python?
data analysis and manipulation tool which includes DataFrames
What is iloc and loc in pandas? Whats the difference?
Way to select specific data from a DataFrame. loc is label based and iloc is index based.
What is set_index in pandas?
sets the index column to what ever column you want. This is useful if you can come up with an index for the dataset which is better than the current one.
What are the coditional selectors in pandas?
isin: lets you select data whose value “is in” a list of values.
ex: reviews.loc[reviews.country.isin([‘Italy’, ‘France’])]
isnull (and it companion notnull): lets you highlight values which are (or are not) empty (NaN).
ex: reviews.loc[reviews.price.notnull()]
What are some summary function in DataFrame?
describe(): This method generates a high-level summary of the attributes of the given column.
-> It is type-aware, meaning that its output changes based on the data type of the input.
mean(): shows the mean of the points allotted
unique(): shows list of unique values
counts(): To see a list of unique values and how often they occur in the dataset
What is mapping in python pandas? What are the functions?
creating new representations from existing data, or for transforming data from the format it is in now to the format that we want it to be in later.
map(): expect a single value from the Series and return a transformed version of that value.
apply(): the equivalent method if we want to transform a whole DataFrame by calling a custom method on each row.
