How to find top 10 elements in MapReduce - python

I am trying to write a Python MapReduce job on some datasets I have to find certain statistics. This is a example of the input data and the form it comes in:
exchange, stock_symbol, date, stock_price_open,stock_price_high,stock_price_low, stock_price_close, stock_volume,stock_price_adj_close.
I need to use the find the top 10 days on which the most stock was traded which is calculated from: stock_price_close * stock_volume
Here is the code I have right now:
from mrjob.job import MRJob
class MapReduce(MRJob):
def mapper(self, _, line):
values = line.split(',')
amount = int(float(values[6]) * float(values[7]))
code = values[1]
date = values[2]
list = (code, date, amount)
yield(None, list)
if __name__ == '__main__':
MapReduce.run()
I'm having trouble implementing a Reducer method for this job however, and not sure how the Reducer will work and find the top 10 elements only. Can anyone help me out here?

Make this a multi-step job. The end result of the first step is per day, the total amount traded. The second gets the totals, sorts them, and returns the top 10.

Related

how to create an avg, price function to loop over 3 index list with N lines in Python

thanks to stack overflow I was able to get help to finish one of the first steps to my project. First steps were to receive 2 files as txt, merge and sort by date. Currently, I am stuck on trying to loop over a list with 3 fields [Date, Buy/Sell, Quantity]. This part of the program must
Check list for first date and if it is a purchase, add to walletList.
If it is a sale, subtract from the previous WalletList Balance.
Create a function to get daily avg. price.
from typing import List
def file_to_list(file: str) -> list:
list= []
with open(file) as f:
for line in f:
list.append(line.strip().replace(";",","))
return list
def merge_list():
bitcoin = file_to_list("bitcoin.txt")
exchange = file_to_list("exchange.txt")
combined = bitcoin + exchange
sorted_combined = sorted(combined)
return sorted_combined
def getBuyorSell(sorted_combined:List):
walletList = []
#transactionDate = [line.split(",")[0] for line in sorted_combined]
#transactionType = [line.split(",")[1] for line in sorted_combined]
for line in sorted_combined:
if line.split(",")[1] == "buy":
walletList.append(line.split(",")[2])
for line in sorted_combined:
if line.split(",")[1] == "sell":
walletList.remove(line.split(",")[2])
str2int = [eval(i) for i in walletList]
totalWallet = sum(str2int)
print(f"Total of wallet: {totalWallet}")
if __name__ == "__main__":
sorted_combined = merge_list()
show_transactions(sorted_combined)
getBuyorSell(sorted_combined)
Price is fixed # 20,000 for ease.
Will implement a price getter for each day in the future.
bitcoin.txt
2022-08-01;buy;100
2022-08-04;buy;50
2022-08-06;buy;10
exchange.txt
2022-08-02;buy;200
2022-08-03;sell;50
2022-08-05;sell;25
Note: getBuyorSell function is sloppy and not working, I am aware of this. Just showed it for all to be able to see my thought process. My work day is over and the office is closing so I won't be able to work on this till tomorrow figured id post it anyways. if this is not okay, I can come back tomorrow to ask a more detailed and better-formed question with a more complete code. However, if anyone can help in the meantime to help guide me, it would be greatly appreciated. (I know I must use calculations to get the avg. price, just used Remove to show the thought process.)

Using program in another file gives different output

I'm having a rather unique issue with my code that I have not experienced before and could use some guidance.
Here is an attempt a short explanation:
Basically, I have a program with many functions that are tied to one main one. It takes in data from files sent to it and gives output based on many factors. Running this function in the file itself gives the proper results, however, if I import this function and run it in the main.py, it gives very, very incorrect output.
I am going to do my best to show the least amount of code in this post, so here is the GitHub. Please use it for further reference and understanding of what is happening. I don't know any websites that I can use to link and run my code for these purposes.
sentiment_analysis.py is the file with all of the functions. main.py is the file that utilizes it all, and driver.py is the file given by my prof to test this assignment.
Basic assignment explanation (skip if not needed for answering the question): Take in twitter data from the files given along with keywords that have an associated happiness value. Take all data, split into timezone regions (approximation based on given point values, not real timezones), and then give back basic information about the data in the files. ie. Average happiness per timezone, total keyword tweets, and total tweets, for each region.
Running sentiment_analysis will currently give correct output based on heavy testing.
Running main and driver will give incorrect output. Ex. tweets2 has 25 total lines of twitter data, but using driver will return 91 total tweets and keyword tweets (eastern data, 4th test scenario in driver.py) instead of the expected 15 total tweets in that region.
I've spent about 3 hours testing scenarios and outputting different information to try and debug but have had no luck. If anyone has any idea why it's returning different outputs when called in a different file, that would be great.
The following are the three most important functions in the file, with the first being the one called in another file.
def compute_tweets(tweets, keywords):
try:
with open(tweets, encoding="utf-8", errors="ignore") as f: # opens the file
tweet_list = f.read().splitlines() # reads and splitlines the file. Gets rid of the \n
print(tweet_list)
with open(keywords, encoding="utf-8", errors="ignore") as f:
keyword_dict = {k: int(v) for line in f for k,v in [line.strip().split(',')]}
# instead of opening this file normally i am using dictionary comprehension to turn the entire file into a dictionary
# instead of the standard list which would come from using the readlines() function.
determine_timezone(tweet_list) # this will run the function to split all pieces of the file into region specific ones
eastern = calculations(keyword_dict, eastern_list)
central = calculations(keyword_dict, central_list)
mountain = calculations(keyword_dict, mountain_list)
pacific = calculations(keyword_dict, pacific_list)
return final_calculation(eastern, central, mountain, pacific)
except FileNotFoundError as excpt:
empty_list = []
print(excpt)
print("One or more of the files you entered does not exist.")
return empty_list
# Constants for Timezone Detection
# eastern begin
p1 = [49.189787, -67.444574]
p2 = [24.660845, -67.444574]
# Central begin, eastern end
p3 = [49.189787, -87.518395]
# p4 = [24.660845, -87.518395] - Not needed
# Mountain begin, central end
p5 = [49.189787, -101.998892]
# p6 = [24.660845, -101.998892] - Not needed
# Pacific begin, mountain end
p7 = [49.189787, -115.236428]
# p8 = [24.660845, -115.236428] - Not needed
# pacific end, still pacific
p9 = [49.189787, -125.242264]
# p10 = [24.660845, -125.242264]
def determine_timezone(tweet_list):
for index, tweet in enumerate(tweet_list): # takes in index and tweet data and creates a for loop
long_lat = get_longlat(tweet) # determines the longlat for the tweet that is currently needed to work on
if float(long_lat[0]) <= float(p1[0]) and float(long_lat[0]) >= float(p2[0]):
if float(long_lat[1]) <= float(p1[1]) and float(long_lat[1]) > float(p3[1]):
# this is testing for the eastern region
eastern_list.append(tweet_list[index])
elif float(long_lat[1]) <= float(p3[1]) and float(long_lat[1]) > float(p5[1]):
# testing for the central region
central_list.append(tweet_list[index])
elif float(long_lat[1]) <= float(p5[1]) and float(long_lat[1]) > float(p7[1]):
# testing for mountain region
mountain_list.append(tweet_list[index])
elif float(long_lat[1]) <= float(p7[1]) and float(long_lat[1]) >= float(p9[1]):
# testing for pacific region
pacific_list.append(tweet_list[index])
else:
# if nothing is found, continue to the next element in the tweet data and do nothing
continue
else:
# if nothing is found for the longitude, then also continue
continue
def calculations(keyword_dict, tweet_list):
# - Constants for caclulations and returns
total_tweets = 0
total_keyword_tweets = 0
average_happiness = 0
happiness_sum = 0
for entry in tweet_list: # saying for each piece of the tweet list
word_list = input_splitting(entry) # run through the input splitting for list of words
total_tweets += 1 # add one to total tweets
keyword_happened_counter = 0 # this is used to know if the word list has already had a keyword tweet. Needs to be
# reset to 0 again in this spot.
for word in word_list: # for each word in that word list
for key, value in keyword_dict.items(): # take the key and respective value for each item in the dict
# print("key:", key, "val:", value)
if word == key: # if the word we got is the same as the key value
if keyword_happened_counter == 0: # and the keyword counter hasnt gone up
total_keyword_tweets += 1 # add one to the total keyword tweets
keyword_happened_counter += 1 # then add one to keyword happened counter
happiness_sum += value # and, if we have a keyword tweet, no matter what add to the happiness sum
else:
continue # if we don't have a word == key, continue iterating.
if total_keyword_tweets != 0:
average_happiness = happiness_sum / total_keyword_tweets # calculation for the average happiness value
else:
average_happiness = 0
return [average_happiness, total_keyword_tweets, total_tweets] # returning a tuple of info in proper order
My apologies for the wall of both text and code. I'm new to making posts on here and am trying to include all relevant information... If anyone knows of a better way to do this aside from using github and code blocks, please do let me know.
Thanks in advance.

CS50 'DNA': Ways to speed up my Week 6 'dna.py' program?

So for this problem I had to create a program that takes in two arguments. A CSV database like this:
name,AGATC,AATG,TATC
Alice,2,8,3
Bob,4,1,5
Charlie,3,2,5
And a DNA sequence like this:
TAAAAGGTGAGTTAAATAGAATAGGTTAAAATTAAAGGAGATCAGATCAGATCAGATCTATCTATCTATCTATCTATCAGAAAAGAGTAAATAGTTAAAGAGTAAGATATTGAATTAATGGAAAATATTGTTGGGGAAAGGAGGGATAGAAGG
My program works by first getting the "Short Tandem Repeat" (STR) headers from the database (AGATC, etc.), then counting the highest number of times each STR repeats consecutively within the sequence. Finally, it compares these counted values to the values of each row in the database, printing out a name if a match is found, or "No match" otherwise.
The program works for sure, but is ridiculously slow whenever ran using the larger database provided, to the point where the terminal pauses for an entire minute before returning any output. And unfortunately this is causing the 'check50' marking system to time-out and return a negative result upon testing with this large database.
I'm presuming the slowdown is caused by the nested loops within the 'STR_count' function:
def STR_count(sequence, seq_len, STR_array, STR_array_len):
# Creates a list to store max recurrence values for each STR
STR_count_values = [0] * STR_array_len
# Temp value to store current count of STR recurrence
temp_value = 0
# Iterates over each STR in STR_array
for i in range(STR_array_len):
STR_len = len(STR_array[i])
# Iterates over each sequence element
for j in range(seq_len):
# Ensures it's still physically possible for STR to be present in sequence
while (seq_len - j >= STR_len):
# Gets sequence substring of length STR_len, starting from jth element
sub = sequence[j:(j + (STR_len))]
# Compares current substring to current STR
if (sub == STR_array[i]):
temp_value += 1
j += STR_len
else:
# Ensures current STR_count_value is highest
if (temp_value > STR_count_values[i]):
STR_count_values[i] = temp_value
# Resets temp_value to break count, and pushes j forward by 1
temp_value = 0
j += 1
i += 1
return STR_count_values
And the 'DNA_match' function:
# Searches database file for DNA matches
def DNA_match(STR_values, arg_database, STR_array_len):
with open(arg_database, 'r') as csv_database:
database = csv.reader(csv_database)
name_array = [] * (STR_array_len + 1)
next(database)
# Iterates over one row of database at a time
for row in database:
name_array.clear()
# Copies entire row into name_array list
for column in row:
name_array.append(column)
# Converts name_array number strings to actual ints
for i in range(STR_array_len):
name_array[i + 1] = int(name_array[i + 1])
# Checks if a row's STR values match the sequence's values, prints the row name if match is found
match = 0
for i in range(0, STR_array_len, + 1):
if (name_array[i + 1] == STR_values[i]):
match += 1
if (match == STR_array_len):
print(name_array[0])
exit()
print("No match")
exit()
However, I'm new to Python, and haven't really had to consider speed before, so I'm not sure how to improve upon this.
I'm not particularly looking for people to do my work for me, so I'm happy for any suggestions to be as vague as possible. And honestly, I'll value any feedback, including stylistic advice, as I can only imagine how disgusting this code looks to those more experienced.
Here's a link to the full program, if helpful.
Thanks :) x
Thanks for providing a link to the entire program. It seems needlessly complex, but I'd say it's just a lack of knowing what features are available to you. I think you've already identified the part of your code that's causing the slowness - I haven't profiled it or anything, but my first impulse would also be the three nested loops in STR_count.
Here's how I would write it, taking advantage of the Python standard library. Every entry in the database corresponds to one person, so that's what I'm calling them. people is a list of dictionaries, where each dictionary represents one line in the database. We get this for free by using csv.DictReader.
To find the matches in the sequence, for every short tandem repeat in the database, we create a regex pattern (the current short tandem repeat, repeated one or more times). If there is a match in the sequence, the total number of repetitions is equal to the length of the match divided by the length of the current tandem repeat. For example, if AGATCAGATCAGATC is present in the sequence, and the current tandem repeat is AGATC, then the number of repetitions will be len("AGATCAGATCAGATC") // len("AGATC") which is 15 // 5, which is 3.
count is just a dictionary that maps short tandem repeats to their corresponding number of repetitions in the sequence. Finally, we search for a person whose short tandem repeat counts match those of count exactly, and print their name. If no such person exists, we print "No match".
def main():
import argparse
from csv import DictReader
import re
parser = argparse.ArgumentParser()
parser.add_argument("database_filename")
parser.add_argument("sequence_filename")
args = parser.parse_args()
with open(args.database_filename, "r") as file:
reader = DictReader(file)
short_tandem_repeats = reader.fieldnames[1:]
people = list(reader)
with open(args.sequence_filename, "r") as file:
sequence = file.read().strip()
count = dict(zip(short_tandem_repeats, [0] * len(short_tandem_repeats)))
for short_tandem_repeat in short_tandem_repeats:
pattern = f"({short_tandem_repeat}){{1,}}"
match = re.search(pattern, sequence)
if match is None:
continue
count[short_tandem_repeat] = len(match.group()) // len(short_tandem_repeat)
try:
person = next(person for person in people if all(int(person[k]) == count[k] for k in short_tandem_repeats))
print(person["name"])
except StopIteration:
print("No match")
return 0
if __name__ == "__main__":
import sys
sys.exit(main())

Activity selection using Greedy Algorithm in Python

Given the problem, I have the following approach however, I am not able to to get all the test cases
Problem Statement: A club has planned to organize several event. The volunteers are given a list of activities and the starting time and ending time of those activities.
Write a python function that accepts the activity list, start_time list and finish_time list. The function should find out and return the list of maximum number of activities that can be performed by a single person.
Assume that a person can work only on a single activity at a time. If an activity performed by a person ends at x unit time then he/she can take up the next activity which is starting at any time greater than or equal to x+1.
def find_maximum_activities(activity_list,start_time_list, finish_time_list):
activities = list(zip(activity_list, start_time_list, finish_time_list))
activities.sort(key = lambda x: x[2])
finish = 0
result = []
for i in activities:
if finish <= i[1]:
result.append(i[0])
finish = i[2]
return result
activity_list=[1,2,3,4,5,6,7]
start_time_list=[1,4,2,3,6,8,6]
finish_time_list=[2,6,4,5,7,10,9]
result=find_maximum_activities(activity_list,start_time_list, finish_time_list)
print("The maximum set of activities that can be completed:",result)
You are missing to update the finish variable.
activities.sort(key=lambda x: x[1])
finish = -1
result = []
for i in activities:
if finish <= i[0]:
result.append(d[i])
finish = i[1]
Try the above snippet.
I don't believe this is a greedy problem.
IMO, it is a DP problem.
Given an Activity you should've computed the answer for each activity that starts after this activity.
So process the activities in decreasing order of start time.
Therefore answer for a given activity will be 1 + max(Answer for all activity that start after this ends).
Make max(Answer for all activity that start after this ends) an O(1) | O(log(n)) operation.

appending array breaks program

I am writing a program to analyze some of our invoice data. Basically,I need to take an array containing each individual invoice we sent out over the past year & break it down into twelve arrays which contains the invoices for that month using the dateSeperate() function, so that monthly_transactions[0] returns Januaries transactions, monthly_transactions[1] returns Februaries & so forth.
I've managed to get it working so that dateSeperate returns monthly_transactions[0] as the january transactions. However, once all of the January data is entered, I attempt to append the monthly_transactions array using line 44. However, this just causes the program to break & become unrepsonsive. The code still executes & doesnt return an error, but Python becomes unresponsive & I have to force quite out of it.
I've been writing the the global array monthly_transactions. dateSeperate runs fine as long as I don't include the last else statement. If I do that, monthly_transactions[0] returns an array containing all of the january invoices. the issue arises in my last else statement, which when added, causes Python to freeze.
Can anyone help me shed any light on this?
I have written a program that defines all of the arrays I'm going to be using (yes I know global arrays aren't good. I'm a marketer trying to learn programming so any input you could give me on how to improve this would be much appreciated
import csv
line_items = []
monthly_transactions = []
accounts_seperated = []
Then I import all of my data and place it into the line_items array
def csv_dict_reader(file_obj):
global board_info
reader = csv.DictReader(file_obj, delimiter=',')
for line in reader:
item = []
item.append(line["company id"])
item.append(line["user id"])
item.append(line["Amount"])
item.append(line["Transaction Date"])
item.append(line["FIrst Transaction"])
line_items.append(item)
if __name__ == "__main__":
with open("ChurnTest.csv") as f_obj:
csv_dict_reader(f_obj)
#formats the transacation date data to make it more readable
def dateFormat():
for i in range(len(line_items)):
ddmmyyyy =(line_items[i][3])
yyyymmdd = ddmmyyyy[6:] + "-"+ ddmmyyyy[:2] + "-" + ddmmyyyy[3:5]
line_items[i][3] = yyyymmdd
#Takes the line_items array and splits it into new array monthly_tranactions, where each value holds one month of data
def dateSeperate():
for i in range(len(line_items)):
#if there are no values in the monthly transactions, add the first line item
if len(monthly_transactions) == 0:
test = []
test.append(line_items[i])
monthly_transactions.append(test)
# check to see if the line items year & month match a value already in the monthly_transaction array.
else:
for j in range(len(monthly_transactions)):
line_year = line_items[i][3][:2]
line_month = line_items[i][3][3:5]
array_year = monthly_transactions[j][0][3][:2]
array_month = monthly_transactions[j][0][3][3:5]
#print(line_year, array_year, line_month, array_month)
#If it does, add that line item to that month
if line_year == array_year and line_month == array_month:
monthly_transactions[j].append(line_items[i])
#Otherwise, create a new sub array for that month
else:
monthly_transactions.append(line_items[i])
dateFormat()
dateSeperate()
print(monthly_transactions)
I would really, really appreciate any thoughts or feedback you guys could give me on this code.
Based on the comments on the OP, your csv_dict_reader function seems to do exactly what you want it to do, at least inasmuch as it appends data from its argument csv file to the top-level variable line_items. You said yourself that if you print out line_items, it shows the data that you want.
"But appending doesn't work." I take it you mean that appending the line_items to monthly_transactions isn't being done. The reason for that is that you didn't tell the program to do it! The appending that you're talking about is done as part of your dateSeparate function, however you still need to call the function.
I'm not sure exactly how you want to use your dateFormat and dateSeparate functions, but in order to use them, you need to include them in the main function somehow as calls, i.e. dateFormat() and dateSeparate().
EDIT: You've created the potential for an endless loop in the last else: section, which extends monthly_transactions by 1 if the line/array year/month aren't equal. This is problematic because it's within the loop for j in range(len(monthly_transactions)):. This loop will never get to the end if the length of monthly_transactions is increased by 1 every time through.

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