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3 Flashcards

1
Q

VC: The most senior person in a VC firm is called a

A

managing director or general partner.

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2
Q

VC: The managing director or general partner

A

make the final decision on which companies to invest in and sit on the board of directors for the companies they invest in.

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3
Q

HostGator: To allow remote sql connections

A

Click “Remote MySQL” and enter the IP address of the computer you want to allow.

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4
Q

HostGator: To create a database, a new user, and give permissions

A

click “MySQL Database Wizard” and go through it.

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5
Q

HostGator: To upload a csv

A

Click on desired db, then click on import tab. Select the csv. Choose the csv file format, then if necessary, click checkbutton for “first line contains table columns”

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6
Q

DB: A simple DB is called

A

sqlite

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7
Q

Windows: To create a new file, type

A

echo.>file_name.py

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8
Q

Windows: To see current directory, type

A

echo %cd%

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9
Q

Windows: To change directory, type

A

cd c:/users/alen.solomon/desktop

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10
Q

Windows: To list all the files in current directory, type

A

dir /b

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11
Q

Pandas: Non printable characters can cause a “ValueError: No columns to parse from file” and can be fixed by

A

adding the parameter encoding=”utf-16” to read_csv

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12
Q

Adwords: When exporting a report from adwords, make sure not to use

A

Excel.csv format

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13
Q

Pandas: To choose a delimiter for read_csv, type

A

sep=”\t”

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14
Q

Pandas: To turn an excel file to a df, type

A 
xl = pandas.ExcelFile("path/to.xlsx")
df = xl.parse("Sheet name")
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15
Q

Pandas: To change column values with a dollar sign to a float, type

A

df[“Cost”] = df[“Cost”].apply(lambda x: str(x).strip(“$”)).astype(float)

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16
Q

Pandas: When you use df[“Column name”].apply(my_function)

A

the function name does not need to end with ()

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17
Q

Pandas: To return only certain columns of a df in a set order, type

A

df = df.ix[ :, [“Abbrev”,”Jan”,”Feb”,”Mar”,”Total”]]

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18
Q

Pandas: To replace all nans with something, type

A

df[“Column name”].fillna(“Replacement”, inplace=True)

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19
Q

Pandas: To write a couple dfs to two sheets in excel, type

A

writer = pandas.ExcelWriter(‘/users/student/desktop/demo.xlsx’, engine=’xlsxwriter’)

df. to_excel(writer, index=False, sheet_name=’Sheet1’)
df2. to_excel(writer, index=False, sheet_name=’Sheet2’)
writer. save()

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20
Q

Windows: To clear the cmd screen, type

A

CLS

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21
Q

Numpy: To turn a numpy array into a matrix, type

A

my_numpy_array.reshape(5,5)

Note: the dimensions are the 5,5

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22
Q

Numpy: To create a boolean index matrix from two numpy matrices, type

A

my_numpy_matrix

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23
Q

Numpy: To turn a numpy matrix back into an array, type

A

my_numpy_matrix.ravel()

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24
Q

Selenium: To import selenium, type

A

from selenium import webdriver

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25
Q

Selenium: To send selenium to a site, type

A

my_browser.get(“http://google.com”)

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26
Q

Selenium: To instantiate Chrome, type

A

my_browser = webdriver.Chrome()

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27
Q

Selenium: To return the title tag, type

A

my_browser.title

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28
Q

Selenium: To find an element on a page by it’s id, type

A

my_element = my_browser.find_element_by_id(“lst-ib”)

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29
Q

Selenium: To press keyboard into a page element, type

A

my_browser.find_element_by_name(“aw”).send_keys(“Send these keys”)

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30
Q

Selenium: To close the browser you instantiated, type

A

my_browser.quit()

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31
Q

Selenium: To submit in an element, type

A

my_element.submit()

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32
Q

Selenium: To simulate an arrow key press, type

A

my_element.send_keys(“my text”, Keys.ARROW_DOWN)

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33
Q

Selenium: To empty a text field, type

A

my_browser.find_element_by_id(“field”).clear()

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34
Q

Seleniun: To click a submit button, type

A

my_browser.find_element_by_id(“submit”).click()

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35
Q

Selenium: To select an element by its class name, type

A

my_browser.find_element_by_class_name(“date-box”)

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36
Q

HTML: The -select> tag is used for

A

Drop down menues

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37
Q

Selenium: To find the first form on a page through its xml path, type

A

my_browser.find_element_by_xpath(“//form[1]”)

Note: the slashes represent moving into the html tags and then the body tags and into the form tags.

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38
Q

Selenium: An easier way to find the submit form button and press it is

A

my_browser.find_element_by_id(“pswrd”).submit()

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39
Q

Selenium: To click a checkbox xpath, type

A

my_browser.find_element_by_xpath(“.//*[@id=’facebook’]/body/div[2]/label[2]”).click()
Note: Find xpath using firepath.

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40
Q

Selenium: The best way to find a checkbox is

A

xpath

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41
Q

Selenium: Sometimes to make an xpath work you need to

A 
remove the [@id="js_5x"] from
//*[@id="js_5x"]/div/ul/li[6]/a/span/span
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42
Q

Selenium: To get the xpath in chrome

A

Inspect element twice and then right click and click “copy xpath”

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43
Q

Selenium: When looking for the path for checkboxes or buttons, often

A

the label, or the outer ridge of button outside of the button text shows the correct path in inspect element rather than the button itself.

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44
Q

Selenium: When uploading a file do not

A

click on the upload button.

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45
Q

Selenium: To upload a file, type

A

my_browser.find_element_by_xpath(“//*/body/div[6]/input”).send_keys(“/users/student/desktop/report.csv”)

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46
Q

Selenium: To select an list item in a drop down menu, type

A

from selenium.webdriver.support.select import Select
select = Select(my_browser.find_element_by_id(“dropdownid”))
select.select_by_visible_text(“Jan”)

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47
Q

Selenium: To make the browser continue looking for a page element if it is not there for a set amount of time, type

A

my_browser.implicitly_wait(50)

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48
Q

Selenium: implicitly_wait(30) only has to be

A

set once and all tests for this browser will have the wait.

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49
Q

BS4: To parse a soup_page for an html tag with a certain parameter (e.g. css class name), type

A

soup_page.find_all(“div”, {“class”: “name”})

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50
Q

BS4: To return a list of all the top level html tags contents separated, type

A

soup_page.contents

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51
Q

BS4: To return the first item in a list of all the top level html tags contents separated, type

A

soup_page.contents[0]

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52
Q

BS4: To return the first item in a list of all the top level html tags contents separated and then the first tags contents from within that list item, type

A

soup_page.contents[0].contents[0]

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53
Q

Python: To use a list comprehension to return a boolean index, type

A

my_list = [1,2,3,4,5,6,7,8]

[item>3 for item in my_list]

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54
Q

IPYNB: To make a graph show up, type

A

%matplotlib inline
import matplotlib.pyplot as plt

df.plot(x=”Column”, y=”Column2”, kind=”scatter”)

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55
Q

Pandas: A series is like a

A

One dimensional array with an index.

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56
Q

Pandas: To set your own index to a Series or df, type

A 
my_index_list = list(range(20))
my_series.index = my_index_list
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57
Q

Pandas: To slice a section of a Series by its index, type

A

my_series.ix[3:6]

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58
Q

Pandas: In order to set a new index for a df or Series, the index list must

A

Be the same length as the df or Series.

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59
Q

BS4: To put the page source of a selenium page into a soup_page, type

A

page = my_browser.page_source

soup_page = BeautifulSoup(page)

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60
Q

Pandas: To return the length and width of a df in a tuple, type

A

df.shape

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61
Q

Pandas: To see how many unique values are in a column, type

A

df[“column name”].unique()

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62
Q

Pandas: Even after you change the index to something other than 0 onward, it will

A

still allow you to slice by the index number

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63
Q

Pandas: To return specific indexes from a Series, type

A

my_series[[ 6, 9, 2]]
or
my_series[[ “A”, “C”, “G”]]

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64
Q

Pandas: If you change the index of a Series to new numbers you cannot use the original index of the numbers unless yo use

A

my_series.iloc[0: 5]
or
my_series.iloc[[4, 6, 9]]

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65
Q

Pandas: The difference between .iloc and .ix when the index is numerical, but doesnt match the zero index is

A

.iloc uses the zero index while .ix uses the current, artificial, index

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66
Q

Pandas: To check if any value in a Series passes a value test, type

A

my_series[my_series > 50].any()

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67
Q

Pandas: To check if all values in a Series passes a value test, type

A

my_series[my_series > 50].all()

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68
Q

Pandas: To sum how many values in a Series pass a value test, type

A

sum(my_series > 5)

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69
Q

Pandas: Can you do a step when slicing a Series

A

Yes

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70
Q

Pandas: df[“Campaign name”] is the data type

A

Series

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71
Q

Pandas: To create a copy of a df, type

A

df_copied = df.copy()

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72
Q

Pandas: To add the rows of one df to another that has the same columns, type

A

df_concated = pandas.concat([df, df2])

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73
Q

Pandas: With regard to nan values, pandas will

A

ignore them

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74
Q

Pandas: When you concatenate two dfs the index will

A

be maintained, so if the dfs were both zero indexed, they there will be duplicates index values.

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75
Q

Pandas: To return the length of a df column, type

A

df[“Column name”].count()

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76
Q

Pandas: Anything action you can perform on a Series can be also performed on a

A

df[“Column name”]

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77
Q

Pandas: To forward fill the na values in a Series, type

A

concated_df.ffill()

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78
Q

Pandas: To backwards fill the na values in a Series, type

A

concated_df.bfill()

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79
Q

Pandas: To replace the index of a concated df with one that is ordered, type

A

concated_df.index = range(concated_df[“Column name”].count())

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80
Q

Pandas: df[“column 1”] + df[“column 1”], is an

A

index based arithmetic. If the indexes are not aligned it will add the wrong rows together.

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81
Q

Pandas: When multiplying two Series, if there are many indices with the same value, pandas will

A

multiply every combination of the values and add new rows for each product.

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82
Q

Pandas: If you decide to create a DataFrame with lists rather than dicts, the column labels will

A

Just be set to zero index numbers.

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83
Q

Pandas: To name unnamed columns, type

A

df.columns = [“Column 1”, “Column 2”]

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84
Q

Pandas: To filter for indexes in a pivot_table, type

A

pvt.query(‘Type == [“Banner”, “Text”]’)

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85
Q

Pandas: To drill down to a certain value in a certain level of a pivot_table, type

A

pvt.xs(“Value name”, level=0)

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86
Q

SQL: To select everything from a table, type

A

SELECT * FROM table

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87
Q

SQL: A databases structure is called it’s

A

schema

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88
Q

SQL: The three main types of data you can set a column to hold are

A

String, Numeric, Date and Time

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89
Q

SQL: The two types of string data are

A

Text and Varchar

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90
Q

SQL: Varchar string type is ideal for

A

Short strings, like names

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91
Q

SQL: Text string type is ideal for

A

Long strings, like descriptions

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92
Q

SQL: The numeric data types are

A

Integers, Fixed Point Decimal, Float

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93
Q

SQL: The fixed point data type

A

Sets a strict number of decimal places and is ideal for dollars

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94
Q

SQL: The float point data type

A

does not set a strict number of decimal places

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95
Q

SQL: The best data type to store a date and time together is

A

datetime

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96
Q

SQL: To create a table with one column that stores 50 characters, type

A

CREATE TABLE tablename (columnname VARCHAR(50));

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97
Q

SQL: To create a table with two columns, one that stores 50 characters, and another that store integers, type

A

CREATE TABLE tablename (columnname VARCHAR(50), columnname INTEGER);

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98
Q

SQL: To insert data into a row, type

A

INSERT INTO table VALUES (“String”, 1000);

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99
Q

SQL: When inserting values into the DB, the values must

A

be in the same order you defined in the table.

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100
Q

SQL: String you insert must have

A

quotes

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101
Q

Facebook: To create free banners, go to

A

www.picmonkey.com

102
Q

Pep 8: Before and after a top level function put

A

two blank lines, not including #comments

103
Q

Pep 8: After every comma and operator, put a

A

space

104
Q

Pep 8: Import libraries

A

on separate lines and at the top with no lines in between

105
Q

Pep 8: Class names should start with a

A

capital letter

106
Q

Pep 8: If putting a comment on the same line as some code

A

precede it by two spaces

107
Q

Pep 8: At the end of a file put

A

an empty line

108
Q

PDB: To use python debugger, type

A

import pdb; pdb.set_trace() above the area you want to debug

109
Q

PDB: To quit the python debugger, type

A

q

110
Q

PDB: To see the return of every variable one by one in order to debug, use

A

python debugger

111
Q

PDB: When finished debugging, make sure to

A

remove pdb

112
Q

PDB: To run the next line of code and return the variable, type

A

next or n

113
Q

Pandas: To turn a pivot_table or groupby back into a filterable table, type

A

pvt.reset_index()

114
Q

Python: Every file that you create is a

A

library

115
Q

Python: To import one specific class, type

A

from library_name import Class_name

116
Q

Python: To create an instance of a class type

A

my_class_instance = Class_name()

117
Q

Python: Functions that belong to classes are called

A

methods

118
Q

Pandas: When importing a csv, to get pandas to recognize a date column, type

A

parse_dates=[“Column name”]

119
Q

Pandas: To merge two dfs but only keep the keys on the left df, type

A

df1.merge(df2, on=”Column”, how=”left”)

120
Q

Pandas: To refer to a column by it’s index instead of it’s name, type

A

df.columns[1]

121
Q

Pandas: When you receive a key error, double check for

A

Extra spaces

122
Q

Pandas: To return a list of all the column labels, type

A

list(df.columns.values)

123
Q

Python: To turn two lists into a dictionary, type

A

dict(zip(list1, list2))

124
Q

Python: To create an invisible command line input for a password, type

A

import getpass

pswd = getpass.getpass(“Password:”)

125
Q

Selenium: To find an element by link text and click it, type

A

my_browser.find_element_by_link_text(“Link text”).click()

126
Q

Selenium: To take a screenshot of the entire page you must

A

use firefox driver. chrome driver currently has a bug.

127
Q

Selenium: The find elements By. types I should remember are

A 
By.PARTIAL_LINK_TEXT
By.XPATH
By.NAME
By.CLASS_NAME
By.TAG_NAME
By.ID
128
Q

Selenium: Screenshots must be saved as a

A

png

129
Q

Selenium: To refresh the current page, type

A

my_browser.refresh()

130
Q

Selenium: To create an explicit wait condition, type

A

from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

wait = WebDriverWait(my_browser, 20)
wait.until(EC.element_to_be_clickable((By.PARTIAL_LINK_TEXT,”Reports”)))

131
Q

Selenium: The find elements By. types I should remember are

A 
By.PARTIAL_LINK_TEXT
By. XPATH
By.NAME
By.CLASS_NAME
By.TAG_NAME
By.ID
132
Q

Selenium: Regarding elements hidden by jquery, Selenium must

A

do what the user must do in order to make it visible.

133
Q

Selenium: To find an element based on anchor text, type

A

my_browser.find_element_by_partial_link_text(“Link text”)

134
Q

Pandas: To convert a Series or column to floats, type

A

df[“Column name”].astype(float)

135
Q

Pandas: To create a new column with values that are conditional on other columns values in the same row.

A

df[“New”] = numpy.where((df[“Column.”]>35) | (df[“Column 2”]==”Banner”), df[“Column2”] * 0.8, df[“Column4”])

136
Q

Pandas: When using both the “or” and “and” conditions,

A

the conditions on both sides of “and” get evaluated together first, before the “or”

137
Q

Pandas: To turn a column into a list type

A

column_list = df[“Column name”].tolist()

138
Q

Pandas: To combine two columns into key value pairs in a dictionary, type

A 
column_list = df["Column name"].tolist()
column_list2 = df["Column name2"].tolist()
combined_dict = dict(zip(column_list, column_list2))
139
Q

Pandas: The purpose of inplace=True is to

A

change the df itself without having to re assign the return of the function to the same df variable name.

140
Q

Pandas: To filter a date formatted column for just a month and year, type

A

df[“2014-11”]

141
Q

Pandas: To place a df with inconsistent dates onto an index with all dates, type

A

df = pandas.DataFrame(index=pandas.date_range(“2014-08-02”, “2014-09-06”, freq=”d”))
df.join(inconsistent_df, how=”outer”)

142
Q

Pandas: Join, by default, merges on the

A

indexes

143
Q

Javascript: To refer to the current page, type

A

document

144
Q

Javascript: To create an alert, type

A

alert(“Hello!”);

145
Q

Javascript: To write an h1 into the current page, type

A

document.write(“<h1>Hello!</h1>”);

146
Q

Javascript: Javascript files end with the filename

A

.js

147
Q

Javascript: To pull javascript code into a webpage from an external file, type

A

-script src=”javascript.js”>-script>

148
Q

Javascript: To print to the console, type

A

console.log(“My log”);

149
Q

Javascript: To create a variable with no value, type

A

var my_var;

150
Q

Javascript: To create a variable with a value, type

A

var my_var = 25;

151
Q

Javascript: Variable name cannot start with

A

a number

152
Q

Javascript: To make a quote be just a quote and not end a string you can use an

A

escape character \ right before it

153
Q

Javascript: To save a user input from a dialog box into a variable, type

A

var dialog_input = prompt(“Text to display”);

154
Q

Javascript: To add a string and a variable using +, type

A

var concated_string = “Hello “ + visitor;

155
Q

Javascript: To update a variable that is referencing itself, type

A 
var message = "Hello ";
message = message + "Dave";
156
Q

Javascript: To update a variable that is referencing itself at the beginning in a shorter way, type

A 
var message = "Hello ";
message += "Dave";
157
Q

Javascript: To return the length of a string type

A

my_string.length;

158
Q

Javascript: To return the lower case of a string, type

A

my_string.toLowerCase();

159
Q

Javascript: To return the upper case of a string, type

A

my_string.toUpperCase();

160
Q

Pandas: To parse dates based on column location instead of column name, type

A

parse_dates=[0]

161
Q

Pandas: To rename a column label by its index, type

A

df.columns.values[0] = “New label”
or
df.rename(columns={df.columns[0]:”New name”})

162
Q

Pandas: To do a value test for nan, type

A

df[“Column”] == numpy.nan

163
Q

Pandas: Pandas deals with nan values by

A

ignoring them

164
Q

Pandas: To turn all of the values in a df to integers, type

A

df = df.astype(int)

165
Q

Pandas: To see a table of correlations, type

A

df.corr()

166
Q

Pandas: To save an image of a matplotlib plot, type

A

import matplotlib.pyplot as plt

my_plot = df.plot(x=”Column”, y=”Column2”, kind=”scatter”)
my_plot.get_figure().savefig(“/users/student/desktop/pii.png”, bbox_inches=”tight”)

167
Q

Pandas: The type of graph df.plot(x=”A”, y=”B”) returns is

A

line

168
Q

Math: The X axis is

A

the bottom going horizontal

169
Q

Matplotlib: The kinds of plots I should remember are

A

bar, scatter, pie, line

170
Q

Python: When creating a big project, remember to

A

Use pep8, document everything starting with “This”, create each part of the project in separate files for easy testing

171
Q

Python: To slice the last 8 characters from a string, type

A

my_string[-8:]

172
Q

Javascript: To turn a string to an integer, type

A

parseInt(var_string)

173
Q

Javascript: To turn a string to a float, type

A

parseFloat(var_string)

174
Q

Python: To round a number to the nearest whole number, type

A

round(1.3)

175
Q

Python: To round a number to the nearest first decimal, type

A

round(1.326, 1)

176
Q

Python: To trigger a python script from another python script, type

A

import os

os.system(“python /users/student/desktop/script.py”)

177
Q

Python: To open a file in its default program, type

A

import subprocess

subprocess.Popen([“open”, “/Applications/Calculator.app/”])

178
Q

Pandas: To delete a column from a df, type

A

df.drop(“column_name”, axis=1, inplace=True)

179
Q

Python: To open any file on a mac, type

A

import subprocess

subprocess.call([“open”, “/Users/student/Desktop/file.app”])

180
Q

Python: To open any file on widows, type

A

import os

os.startfile(c:/filename/path)

181
Q

Python: To delete a file from computer, type

A

import os

os.remove(“/users/student/desktop/file.png”)

182
Q

Pandas: To read_csv for specific columns, type

A

usecols=range(1,7)

183
Q

Pandas: The usecols argument for read_csv must be

A

explicit by either index or label, but not a slice

184
Q

Pandas: To find the highest value in a series, type

A

my_series.max()

185
Q

Pandas: The .apply method does not have

A

access to the index. Must use df.index.map() in the case where you must create a column based on the index.

186
Q

Pandas: To reference a date_range index to create a new column with the day of the week, type

A

df[“Day”] = df.index.map(lambda x: x.strftime(“%A”))

187
Q

Pandas: To add two new values to the bottom of a df, type

A

df = df.append([[“value1”, “value2”]], ignore_index=True)

188
Q

Pandas: To get the number of rows in each of a groupby’s keys, type

A

grouped.size()

189
Q

ML: Supervised learning is when

A

The machine learns by labeled examples. The data sample you teach it with must be labeled and then it will start to predict.

190
Q

ML: A common ratio of a training data set to a testing dataset is

A

67% train to 33% test.

191
Q

ML: Naive bayes is useful for datasets with

A

less than 100k samples and text data

192
Q

ML: Data sets must be

A

Labeled

193
Q

Scraping: Remember before beginning the scraping loop to

A

create the variable that will hold the results and import BeautifulSoup

194
Q

ML: Learning new classifiers as you receive data without doing a batch update is called

A

online learning

195
Q

ML: When some features are missing it is known as

A

“missing features”

196
Q

ML: In non-online cases, when new features become available, you would need to

A

re-fit the model based on a new batch.

197
Q

ML: After you have a batch of samples you need to

A

Fit a model to it.

198
Q

Pandas: When parsing the XL file sheet, the sheet name is

A

Case sensitive

199
Q

Pandas: the to_csv command must be used on a

A

df. eg. df.to_csv(“path/to/file.csv”)

200
Q

Pandas: When using df.append([[val1, val2]], ignore_index=True), remember to

A

reassign the df value to the appended version. e.g. df = df.append([[val1, val2]], ignore_index=True)

201
Q

ML: A dimension is a

A

column

202
Q

ML: In ML, every pixel of an image is its own

A

Dimension/column

203
Q

sklearn: Before you can train a model, you need to

A

instantiate it.

204
Q

sklearn: To instantiate a regression model, type

A

from sklearn.linear_model import LinearRegression

model = LinearRegression()

205
Q

sklearn: To pass an estimator your data you must call the method

A

model.fit(x, y)

206
Q

sklearn: The x and y parameters in the model.fit(x, y) method take in

A 
x = samples by features
y = the labels
207
Q

sklearn: Given a trained model, to predict the label of a new data sample by highest probability, type

A

model.predict([[feature_value, feature_value, feature_value]])

208
Q

sklearn: To return the probability that a new data set has each label, type

A

model.predict_proba()

209
Q

ML: To use categorical data, you must

A

Binarize it into separate columns.

This is because models assume that if it is in the same column that it is a range, like length or height.

210
Q

sklearn: The LinearRegression model

A

plots a line through the data and based on the y axis return x.

211
Q

sklearn: The DecisionTreeRegressor

A

Hold all samples in a library and compares new data to the sample and returns the label that matched closest.

212
Q

sklearn: A classification task is when

A

You give a model samples with features and have it predict the label.

213
Q

sklearn: Parameters defined by training have a

A

trailing underscore

214
Q

sklearn: The basic format for a ML prediction generator is

A

from sklearn.chosenlibrary import ChosenClass
model = ChosenClass()
x = samplesbyfeaturesdata
y = targetlabels
model.fit(x, y)
model.predict([[feature_val, feature_val2, feature_val3]])

215
Q

sklearn: clf stands for

A

classifier

216
Q

sklearn: To import the cross validation module, type

A

from sklearn import cross_validation

217
Q

sklearn: To fit a model and then cross validate it, type

A

from sklearn import cross_validation
from sklearn.chosenlibrary import ChosenClass
x = samplebyfeaturedata
y = targetlabels
X_train, X_test, y_train, y_test = cross_validation.train_test_split(x, y, test_size=0.25, random_state=0)
clf = ChosenClass()
clf.fit(x, y)
pred = clf.predict(X_test)
from sklearn.metrics import accuracy_score
accuracy_score(pred, y_test)

218
Q

SQL: Database normalization usually involves

A

dividing large tables into smaller (and less redundant) tables and defining relationships between them.

219
Q

Numpy: To see the number of rows and columns in a numpy array

A

my_numpy_array.shape

220
Q

Numpy: To convert a pandas DataFrame to a numpy array, type

A

my_numpy_array = array(df)

221
Q

sklearn: clf stands for

A

classifier.

222
Q

ML: Natural language processing is

A

Training a computer to understand the meaning of words.

223
Q

ML: A decision surface is

A

a boundary on a scatter plot that divides two different types of data

224
Q

sklearn: To return the accuracy of a prediction to the test labels, type

A 
from sklearn.metrics import accuracy_score
pred = clf.predict(features_test)
accuracy_score(pred, labels_test)
or
model.score(feature_test, label_test)
225
Q

sklearn: To import naive bayes, type

A

from sklearn.naive_bayes import GaussianNB

226
Q

Pandas: To return just the fourth column of a df, type

A

df.ix[:,3:4]

227
Q

sklearn: Does not accept values of the type

A

string

228
Q

sklearn: To import and instantiate a decision tree classifier, type

A

from sklearn import tree

clf = tree.DecisionTreeClassifier()

229
Q

DecisionTreeClassifier: The DecisionTreeClassifier segments the data in a

A

blocky and slicy manner.

230
Q

DecisionTreeClassifier: The min_samples_split parameter controls

A

How many data samples are necessary for the DecisionTree decision boundary line to turn to fit them.

231
Q

DecisionTreeClassifier: Entropy is

A

a measure of impurity of the data samples and controls how impure the data must get before splitting.

232
Q

DecisionTreeClassifier: The default parameter for DecisionTreeClassifier that tunes entropy is

A

“gini”

233
Q

DecisionTreeClassifier: DecisionTreeClassifier is prone to

A

overfitting

234
Q

KNeighborsClassifier: The KNeighborsClassifier predicts by

A

a simple majority vote of the nearest neighbors of each test point

235
Q

NaiveBayes: NaiveBayes classifies by using

A

correlation with each feature independently to guide classification. It does not group features.

236
Q

Numpy: To convert a two dimensional numpy array to a no dimensional numpy array, type

A

my_numpy_array.ravel()

237
Q

Pandas: To parse dates where the day, month and year are in separate columns, type

A

parse_dates={“Dates”:[“Day”, “Month”, “Year”]}

238
Q

Pandas: To bin data from a column in a new column, type

A

ranges = [0,6,12,18,24]
labels = [“AM”,”AM”,”PM”,”PM”,”PM”]
df[“New column”] = pandas.cut(df[“column name”], ranges, labels = labels)

239
Q

Pandas: To save a csv without the index, type

A

df.to_csv(“path.csv”, index=False)

240
Q

Pandas: To make a specific cell a nan value, type

A

df.iloc[1,1] = numpy.nan

241
Q

Pandas: To remove rows with nan values, type

A

df = df.dropna()

242
Q

Pandas: To convert an excel file to a df, do not try to

A

save the excel file as a csv and the read_csv, it will unicode error

243
Q

Pandas: You cannot df.drop() the

A

header

244
Q

Pandas: To change the header to another row in the df, type

A

df.columns = df.iloc[1]

245
Q

python: to return the last index where the substring is found, type

A

my_string.rfind(“substring”)

246
Q

pandas: When getting a nonetype is not … error using .apply(lambda x: x) use the

A

str(x) or int(x) method to convert the objects to string

247
Q

pandas: iterrows() returns

A

a tuple of the index and the row data

248
Q

When creating automation scripts always add some

A

logging

note: Not the same character every time

249
Q

python: To make a one line if else statement, type

A

“true value” if 10==10 else “false_value”

250
Q

python: Think of a virtual env as

A

an environment you are running your script with, not a place you are saving your scripts.

freingt (64 decks)

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