I want to write a function that creates a data frame from an already existing dataframe and then concatenate them all into one dataframe but am struggling finding a way to make a unique dataframe each time the function is called. I believe I need to make a dictionary and then add the new code to the dictionary but im struggling finding a way to save the dataframe under a unique ID each time the function is called. Here is some code:
def week1_function(data, conca_data):
#Grabbing the string of column name
pd_variable = data.loc[0,'YR']
#Using this for the week string
wk_variable = '1x'
#Slicing the period from the column name of year period
pd_slice = pd_variable[-2:]
#Slicing the year from the year period
yr_variable = pd_variable[0:4]
data['YR'] = yr_variable
data['WK_PD'] = wk_variable + pd_slice
data = data[['LOCATION','YR', 'WK_PD', 'WK1_SHIP_CASE']]
concadate = data
def week2_function(data, new_df):
#Grabbing the string of column name
pd_variable = data.loc[0,'YR']
#Using this for the week string
wk_variable = '2x'
#Slicing the period from the column name of year period
pd_slice = pd_variable[-2:]
#Slicing the year from the year period
yr_variable = pd_variable[0:4]
data['YR'] = yr_variable
data['WK_PD'] = wk_variable + pd_slice
data = data[['LOCATION','YR', 'WK_PD', 'WK2_SHIP_CASE']]
new_df = data
Each time I call these on the massive dataset for each site, is there a way to save it under a unique dataframe name so I can eventually concatenate them all when their under the same new table format that I now created?
On Pandas 1.3.4 and Python 3.9.
So I'm having issues filtering for a partial piece of the string. The "Date" column is listed in the format of MM/DD/YYYY HH:MM:SS A/PM where the most recent one is on top. If the date is single digit (example: November 3rd), it does not have the 0 such that it is 11/3 instead of 11/03. Basically I'm looking to go look at column named "Date" and have python read parts of the string to filter for only today.
This is what the original csv looks like. This is what I want to do to the file. Basically looking for a specific date but not any time of that date and implement the =RIGHT() formula. However this is what I end up with with the following code.
from datetime import date
import pandas as pd
df = pd.read_csv(r'file.csv', dtype=str)
today = date.today()
d1 = today.strftime("%m/%#d/%Y") # to find out what today is
df = pd.DataFrame(df, columns=['New Phone', 'Phone number', 'Date'])
df['New Phone'] = df['Phone number'].str[-10:]
df_today = df['Date'].str.contains(f'{d1}',case=False, na=False)
df_today.to_csv(r'file.csv', index=False)
This line is wrong:
df_today = df['Date'].str.contains(f'{d1}',case=False, na=False)
All you're doing there is creating a mask; essentially what that is is just a Pandas series, containg True or False in each row, according to the condition you created the mask in. The spreadsheet get's only FALSE as you showed because non of the items in the Date contain the string that the variable d1 holds...
Instead, try this:
from datetime import date
import pandas as pd
# Load the CSV file, and change around the columns
df = pd.DataFrame(pd.read_csv(r'file.csv', dtype=str), columns=['New Phone', 'Phone number', 'Date'])
# Take the last ten chars of each phone number
df['New Phone'] = df['Phone number'].str[-10:]
# Convert each date string to a pd.Timestamp, removing the time
df['Date'] = pd.to_datetime(df['Date'].str.split(r'\s+', n=1).str[0])
# Get the phone numbers that are from today
df_today = df[df['Date'] == date.today().strftime('%m/%d/%Y')]
# Write the result to the CSV file
df_today.to_csv(r'file.csv', index=False)
I am working on a personal project collecting the data on Covid-19 cases. The data set only shows the total number of Covid-19 cases per state cumulatively. I would like to add a column that contains the new cases added that day. This is what I have so far:
import pandas as pd
from datetime import date
from datetime import timedelta
import numpy as np
#read the CSV from github
hist_US_State = pd.read_csv("https://raw.githubusercontent.com/nytimes/covid-19-data/master/us-states.csv")
#some code to get yesterday's date and the day before which is needed later.
today = date.today()
yesterday = today - timedelta(days = 1)
yesterday = str(yesterday)
day_before_yesterday = today - timedelta(days = 2)
day_before_yesterday = str(day_before_yesterday)
#Extracting yesterday's and the day before cases and combine them in one dataframe
yesterday_cases = hist_US_State[hist_US_State["date"] == yesterday]
day_before_yesterday_cases = hist_US_State[hist_US_State["date"] == day_before_yesterday]
total_cases = pd.DataFrame()
total_cases = day_before_yesterday_cases.append(yesterday_cases)
#Adding a new column called "new_cases" and this is where I get into trouble.
total_cases["new_cases"] = yesterday_cases["cases"] - day_before_yesterday_cases["cases"]
Can you please point out what I am doing wrong?
Because you defined total_cases as a concatenation (via append) of yesterday_cases and day_before_yesterday_cases, its number of rows is equal to the sum of the other two dataframes. It looks like yesterday_cases and day_before_yesterday_cases both have 55 rows, and so total_cases has 110 rows. Thus your last line is trying to assign 55 values to a series of 110 values.
You may either want to reshape your data so that each date is its own column, or work in arrays of dataframes.
I am fairly new to python and coding in general.
I have a big data file that provides daily data for the period 2011-2018 for a number of stock tickers (300~).
The data is a .csv file with circa 150k rows and looks as follows (short example):
Date,Symbol,ShortExemptVolume,ShortVolume,TotalVolume
20110103,AAWW,0.0,28369,78113.0
20110103,AMD,0.0,3183556,8095093.0
20110103,AMRS,0.0,14196,18811.0
20110103,ARAY,0.0,31685,77976.0
20110103,ARCC,0.0,177208,423768.0
20110103,ASCMA,0.0,3930,26527.0
20110103,ATI,0.0,193772,301287.0
20110103,ATSG,0.0,23659,72965.0
20110103,AVID,0.0,7211,18896.0
20110103,BMRN,0.0,21740,213974.0
20110103,CAMP,0.0,2000,11401.0
20110103,CIEN,0.0,625165,1309490.0
20110103,COWN,0.0,3195,24293.0
20110103,CSV,0.0,6133,25394.0
I have a function that allows me to filter for a specific symbol and get 10 observations before and after a specified date (could be any date between 2011 and 2018).
import pandas as pd
from datetime import datetime
import urllib
import datetime
def get_data(issue_date, stock_ticker):
df = pd.read_csv (r'D:\Project\Data\Short_Interest\exampledata.csv')
df['Date'] = pd.to_datetime(df['Date'], format="%Y%m%d")
d = df
df = pd.DataFrame(d)
short = df.loc[df.Symbol.eq(stock_ticker)]
# get the index of the row of interest
ix = short[short.Date.eq(issue_date)].index[0]
# get the item row for that row's index
iloc_ix = short.index.get_loc(ix)
# get the +/-1 iloc rows (+2 because that is how slices work), basically +1 and -1 trading days
short_data = short.iloc[iloc_ix-10: iloc_ix+11]
return [short_data]
I want to create a script that iterates a list of 'issue_dates' and 'stock_tickers'. The list (a .csv) looks as following:
ARAY,07/08/2017
ARAY,24/04/2014
ACETQ,16/11/2015
ACETQ,16/11/2015
NVLNA,15/08/2014
ATSG,29/09/2017
ATI,24/05/2016
MDRX,18/06/2013
MDRX,18/06/2013
AMAGX,10/05/2017
AMAGX,14/02/2014
AMD,14/09/2016
To break down my problem and question I would like to know how to do the following:
First, how do I load the inputs?
Second, how do I call the function on each input?
And last, how do I accumulate all the function returns in one dataframe?
To load the inputs and call the function for each row; iterate over the csv file and pass each row's values to the function and accumulate the resulting Seriesin a list.
I modified your function a bit: removed the DataFrame creation so it is only done once and added a try/except block to account for missing dates or tickers (your example data didn't match up too well). The dates in the second csv look like they are day/month/year so I converted them for that format.
import pandas as pd
import datetime, csv
def get_data(df, issue_date, stock_ticker):
'''Return a Series for the ticker centered on the issue date.
'''
short = df.loc[df.Symbol.eq(stock_ticker)]
# get the index of the row of interest
try:
ix = short[short.Date.eq(issue_date)].index[0]
# get the item row for that row's index
iloc_ix = short.index.get_loc(ix)
# get the +/-1 iloc rows (+2 because that is how slices work), basically +1 and -1 trading days
short_data = short.iloc[iloc_ix-10: iloc_ix+11]
except IndexError:
msg = f'no data for {stock_ticker} on {issue_date}'
#log.info(msg)
print(msg)
short_data = None
return short_data
df = pd.read_csv (datafile)
df['Date'] = pd.to_datetime(df['Date'], format="%Y%m%d")
results = []
with open('issues.csv') as issues:
for ticker,date in csv.reader(issues):
day,month,year = map(int,date.split('/'))
# dt = datetime.datetime.strptime(date, r'%d/%m/%Y')
date = datetime.date(year,month,day)
s = get_data(df,date,ticker)
results.append(s)
# print(s)
Creating a single DataFrame or table for all that info may be problematic especially since the date ranges are all different. Probably should ask a separate question regarding that. Its mcve should probably just include a few minimal Pandas Series with a couple of different date ranges and tickers.
I have a lisit of DataFrames that come from the census api, i had stored each year pull into a list.
So at the end of my for loop i have a list with dataframes per year and a list of years to go along side the for loop.
The problem i am having is merging all the DataFrames in the list while also taging them with a list of years.
So i have tried using the reduce function, but it looks like it only taking 2 of the 6 Dataframes i have.
concat just adds them to the dataframe with out tagging or changing anything
# Dependencies
import pandas as pd
import requests
import json
import pprint
import requests
from census import Census
from us import states
# Census
from config import (api_key, gkey)
year = 2012
c = Census(api_key, year)
for length in range(6):
c = Census(api_key, year)
data = c.acs5.get(('NAME', "B25077_001E","B25064_001E",
"B15003_022E","B19013_001E"),
{'for': 'zip code tabulation area:*'})
data_df = pd.DataFrame(data)
data_df = data_df.rename(columns={"NAME": "Name",
"zip code tabulation area": "Zipcode",
"B25077_001E":"Median Home Value",
"B25064_001E":"Median Rent",
"B15003_022E":"Bachelor Degrees",
"B19013_001E":"Median Income"})
data_df = data_df.astype({'Zipcode':'int64'})
filtervalue = data_df['Median Home Value']>0
filtervalue2 = data_df['Median Rent']>0
filtervalue3 = data_df['Median Income']>0
cleandata = data_df[filtervalue][filtervalue2][filtervalue3]
cleandata = cleandata.dropna()
yearlst.append(year)
datalst.append(cleandata)
year += 1
so this generates the two seperate list one with the year and other with dataframe.
So my output came out to either one Dataframe with missing Dataframe entries or it just concatinated all without changing columns.
what im looking for is how to merge all within a list, but datalst[0] to be tagged with yearlst[0] when merging if at all possible
No need for year list, simply assign year column to data frame. Plus avoid incrementing year and have it the iterator column. In fact, consider chaining your process:
for year in range(2012, 2019):
c = Census(api_key, year)
data = c.acs5.get(('NAME', "B25077_001E","B25064_001E", "B15003_022E","B19013_001E"),
{'for': 'zip code tabulation area:*'})
cleandata = (pd.DataFrame(data)
.rename(columns={"NAME": "Name",
"zip code tabulation area": "Zipcode",
"B25077_001E": "Median_Home_Value",
"B25064_001E": "Median_Rent",
"B15003_022E": "Bachelor_Degrees",
"B19013_001E": "Median_Income"})
.astype({'Zipcode':'int64'})
.query('(Median_Home_Value > 0) & (Median_Rent > 0) & (Median_Income > 0)')
.dropna()
.assign(year_column = year)
)
datalst.append(cleandata)
final_data = pd.concat(datalst, ignore_index = True)