striding through pandas dataframe - python

I have a Dataframe of the form
date_time uids
2018-10-16 23:00:00 1000,1321,7654,1321
2018-10-16 23:10:00 7654
2018-10-16 23:20:00 NaN
2018-10-16 23:30:00 7654,1000,7654,1321,1000
2018-10-16 23:40:00 691,3974,3974,323
2018-10-16 23:50:00 NaN
2018-10-17 00:00:00 NaN
2018-10-17 00:10:00 NaN
2018-10-17 00:20:00 27,33,3974,3974,7665,27
This is a very big data frame containing the 5 mins time interval and the number of appearances of ids during those time intervals.
I want to iterate over these DataFrame 6 rows at a time (corresponding to 1 hour) and create DataFrame containing the ID and the number of times each id appear during this time.
Expected output is one dataframe per hour information. For example, in the above case dataframe for the hour 23 - 00 will have this form
uid 1 2 3 4 5 6
1000 1 0 0 2 0 0
1321 2 0 0 1 0 0
and so on
How can I do this efficiently?

I don't have an exact solution but you could create a pivot table: ids on the index and datetimes on the columns. Then you just have to select the columns you want.
import pandas as pd
import numpy as np
df = pd.DataFrame(
{
"date_time": [
"2018-10-16 23:00:00",
"2018-10-16 23:10:00",
"2018-10-16 23:20:00",
"2018-10-16 23:30:00",
"2018-10-16 23:40:00",
"2018-10-16 23:50:00",
"2018-10-17 00:00:00",
"2018-10-17 00:10:00",
"2018-10-17 00:20:00",
],
"uids": [
"1000,1321,7654,1321",
"7654",
np.nan,
"7654,1000,7654,1321,1000",
"691,3974,3974,323",
np.nan,
np.nan,
np.nan,
"27,33,3974,3974,7665,27",
],
}
)
df["date_time"] = pd.to_datetime(df["date_time"])
df = (
df.set_index("date_time") #do not use set_index if date_time is current index
.loc[:, "uids"]
.str.extractall(r"(?P<uids>\d+)")
.droplevel(level=1)
) # separate all the ids
df["number"] = df.index.minute.astype(float) / 10 + 1 # get the number 1 to 6 depending on the minutes
df_pivot = df.pivot_table(
values="number",
index="uids",
columns=["date_time"],
) #dataframe with all the uids on the index and all the datetimes in columns.
You can apply this to the whole dataframe or just a subset containing 6 rows. Then you rename your columns.

You can use the function crosstab:
df['uids'] = df['uids'].str.split(',')
df = df.explode('uids')
df['date_time'] = df['date_time'].dt.minute.floordiv(10).add(1)
pd.crosstab(df['uids'], df['date_time'], dropna=False)
Output:
date_time 1 2 3 4 5 6
uids
1000 1 0 0 2 0 0
1321 2 0 0 1 0 0
27 0 0 2 0 0 0
323 0 0 0 0 1 0
33 0 0 1 0 0 0
3974 0 0 2 0 2 0
691 0 0 0 0 1 0
7654 1 1 0 2 0 0
7665 0 0 1 0 0 0

We can achieve this with extracting the minutes from your datetime column. Then using pivot_table to get your wide format:
df['date_time'] = pd.to_datetime(df['date_time'])
df['minute'] = df['date_time'].dt.minute // 10
piv = (df.assign(uids=df['uids'].str.split(','))
.explode('uids')
.pivot_table(index='uids', columns='minute', values='minute', aggfunc='size')
)
minute 0 1 2 3 4
uids
1000 1.0 NaN NaN 2.0 NaN
1321 2.0 NaN NaN 1.0 NaN
27 NaN NaN 2.0 NaN NaN
323 NaN NaN NaN NaN 1.0
33 NaN NaN 1.0 NaN NaN
3974 NaN NaN 2.0 NaN 2.0
691 NaN NaN NaN NaN 1.0
7654 1.0 1.0 NaN 2.0 NaN
7665 NaN NaN 1.0 NaN NaN

Related

Pandas DataFrame Change Values Based on Values in Different Rows

I have a DataFrame of store sales for 1115 stores with dates over about 2.5 years. The StateHoliday column is a categorical variable indicating the type of holiday it is. See the piece of the df below. As can be seen, b is the code for Easter. There are other codes for other holidays.
Piece of DF
My objective is to analyze sales before and during a holiday. The way I seek to do this is to change the value of the StateHoliday column to something unique for the few days before a particular holiday. For example, b is the code for Easter, so I could change the value to b- indicating that the day is shortly before Easter. The only way I can think to do this is to go through and manually change these values for certain dates. There aren't THAT many holidays, so it wouldn't be that hard to do. But still very annoying!
Tom, see if this works for you, if not please provide additional information:
In the file I have the following data:
Store,Sales,Date,StateHoliday
1,6729,2013-03-25,0
1,6686,2013-03-26,0
1,6660,2013-03-27,0
1,7285,2013-03-28,0
1,6729,2013-03-29,b
1115,10712,2015-07-01,0
1115,11110,2015-07-02,0
1115,10500,2015-07-03,0
1115,12000,2015-07-04,c
import pandas as pd
fname = r"D:\workspace\projects\misc\data\holiday_sales.csv"
df = pd.read_csv(fname)
df["Date"] = pd.to_datetime(df["Date"])
holidays = df[df["StateHoliday"]!="0"].copy(deep=True) # taking only holidays
dictDate2Holiday = dict(zip(holidays["Date"].tolist(), holidays["StateHoliday"].tolist()))
look_back = 2 # how many days back you want to go
holiday_look_back = []
# building a list of pairs (prev days, holiday code)
for dt, h in dictDate2Holiday.items():
prev = dt
holiday_look_back.append((prev, h))
for i in range(1, look_back+1):
prev = prev - pd.Timedelta(days=1)
holiday_look_back.append((prev, h))
dfHolidayLookBack = pd.DataFrame(holiday_look_back, columns=["Date", "StateHolidayNew"])
df = df.merge(dfHolidayLookBack, how="left", on="Date")
df["StateHolidayNew"].fillna("0", inplace=True)
print(df)
columns StateHolidayNew should have the info you need to start analyzing your data
Assuming you have a dataframe like this:
Store Sales Date StateHoliday
0 2 4205 2016-11-15 0
1 1 684 2016-07-13 0
2 2 8946 2017-04-15 0
3 1 6929 2017-02-02 0
4 2 8296 2017-10-30 b
5 1 8261 2015-10-05 0
6 2 3904 2016-08-22 0
7 1 2613 2017-12-30 0
8 2 1324 2016-08-23 0
9 1 6961 2015-11-11 0
10 2 15 2016-12-06 a
11 1 9107 2016-07-05 0
12 2 1138 2015-03-29 0
13 1 7590 2015-06-24 0
14 2 5172 2017-04-29 0
15 1 660 2016-06-21 0
16 2 2539 2017-04-25 0
What you can do is group the values between the different alphabets which represent the holidays and then groupby to find out the sales according to each group. An improvement to this would be to backfill the numbers before the groups, exp., groups=0.0 would become b_0 which would make it easier to understand the groups and what holiday they represent, but I am not sure how to do that.
df['StateHolidayBool'] = df['StateHoliday'].str.isalpha().fillna(False).replace({False: 0, True: 1})
df = df.assign(group = (df[~df['StateHolidayBool'].between(1,1)].index.to_series().diff() > 1).cumsum())
df = df.assign(groups = np.where(df.group.notna(), df.group, df.StateHoliday)).drop(['StateHolidayBool', 'group'], axis=1)
df[~df['groups'].str.isalpha().fillna(False)].groupby('groups').sum()
Output:
Store Sales
groups
0.0 6 20764
1.0 7 23063
2.0 9 26206
Final DataFrame:
Store Sales Date StateHoliday groups
0 2 4205 2016-11-15 0 0.0
1 1 684 2016-07-13 0 0.0
2 2 8946 2017-04-15 0 0.0
3 1 6929 2017-02-02 0 0.0
4 2 8296 2017-10-30 b b
5 1 8261 2015-10-05 0 1.0
6 2 3904 2016-08-22 0 1.0
7 1 2613 2017-12-30 0 1.0
8 2 1324 2016-08-23 0 1.0
9 1 6961 2015-11-11 0 1.0
10 2 15 2016-12-06 a a
11 1 9107 2016-07-05 0 2.0
12 2 1138 2015-03-29 0 2.0
13 1 7590 2015-06-24 0 2.0
14 2 5172 2017-04-29 0 2.0
15 1 660 2016-06-21 0 2.0
16 2 2539 2017-04-25 0 2.0

Combining two dataframes

I've tried merging two dataframes, but I can't seem to get it to work. Each time I merge, the rows where I expect values are all 0. Dataframe df1 already as some data in it, with some left blank. Dataframe df2 will populate those blank rows in df1 where column names match at each value in "TempBin" and each value in "Month" in df1.
EDIT:
Both dataframes are in a for loop. df1 acts as my "storage", df2 changes for each location iteration. So if df2 contained the results for LocationZP, I would also want that data inserted in the matching df1 rows. If I use df1 = df1.append(df2) in the for loop, all of the rows from df2 keep inserting at the very end of df1 for each iteration.
df1:
Month TempBin LocationAA LocationXA LocationZP
1 0 7 1 2
1 1 98 0 89
1 2 12 23 38
1 3 3 14 17
1 4 7 9 14
1 5 1 8 99
13 0 0 0 0
13 1 0 0 0
13 2 0 0 0
13 3 0 0 0
13 4 0 0 0
13 5 0 0 0
df2:
Month TempBin LocationAA
13 0 11
13 1 22
13 2 33
13 3 44
13 4 55
13 5 66
desired output in df1:
Month TempBin LocationAA LocationXA LocationZP
1 0 7 1 2
1 1 98 0 89
1 2 12 23 38
1 3 3 14 17
1 4 7 9 14
1 5 1 8 99
13 0 11 0 0
13 1 22 0 0
13 2 33 0 0
13 3 44 0 0
13 4 55 0 0
13 5 66 0 0
import pandas as pd
df1 = pd.DataFrame({'Month': [1]*6 + [13]*6,
'TempBin': [0,1,2,3,4,5]*2,
'LocationAA': [7,98,12,3,7,1,0,0,0,0,0,0],
'LocationXA': [1,0,23,14,9,8,0,0,0,0,0,0],
'LocationZP': [2,89,38,17,14,99,0,0,0,0,0,0]}
)
df2 = pd.DataFrame({'Month': [13]*6,
'TempBin': [0,1,2,3,4,5],
'LocationAA': [11,22,33,44,55,66]}
)
df1 = pd.merge(df1, df2, on=["Month","TempBin","LocationAA"], how="left")
result:
Month TempBin LocationAA LocationXA LocationZP
1 0 7.0 1.0 2.0
1 1 98.0 0.0 89.0
1 2 12.0 23.0 38.0
1 3 3.0 14.0 17.0
1 4 7.0 9.0 14.0
1 5 1.0 8.0 99.0
13 0 NaN NaN NaN
13 1 NaN NaN NaN
13 2 NaN NaN NaN
13 3 NaN NaN NaN
13 4 NaN NaN NaN
13 5 NaN NaN NaN
Here's some code that worked for me:
# Merge two df into one dataframe on the columns "TempBin" and "Month" filling nan values with 0.
import pandas as pd
df1 = pd.DataFrame({'Month': [1]*6 + [13]*6,
'TempBin': [0,1,2,3,4,5]*2,
'LocationAA': [7,98,12,3,7,1,0,0,0,0,0,0],
'LocationXA': [1,0,23,14,9,8,0,0,0,0,0,0],
'LocationZP': [2,89,38,17,14,99,0,0,0,0,0,0]}
)
df2 = pd.DataFrame({'Month': [13]*6,
'TempBin': [0,1,2,3,4,5],
'LocationAA': [11,22,33,44,55,66]})
df_merge = pd.merge(df1, df2, how='left',
left_on=['TempBin', 'Month'],
right_on=['TempBin', 'Month'])
df_merge.fillna(0, inplace=True)
# add column LocationAA and fill it with the not null value from column LocationAA_x and LocationAA_y
df_merge['LocationAA'] = df_merge.apply(lambda x: x['LocationAA_x'] if pd.isnull(x['LocationAA_y']) else x['LocationAA_y'], axis=1)
# remove column LocationAA_x and LocationAA_y
df_merge.drop(['LocationAA_x', 'LocationAA_y'], axis=1, inplace=True)
print(df_merge)
Output:
Month TempBin LocationXA LocationZP LocationAA
0 1 0 1.0 2.0 0.0
1 1 1 0.0 89.0 0.0
2 1 2 23.0 38.0 0.0
3 1 3 14.0 17.0 0.0
4 1 4 9.0 14.0 0.0
5 1 5 8.0 99.0 0.0
6 13 0 0.0 0.0 11.0
7 13 1 0.0 0.0 22.0
8 13 2 0.0 0.0 33.0
9 13 3 0.0 0.0 44.0
10 13 4 0.0 0.0 55.0
11 13 5 0.0 0.0 66.0
Let me know if there's something you don't understand in the comments :)
PS: Sorry for the extra comments. But I left them there for some more explanations.
You need to use append to get the desired output:
df1 = df1.append(df2)
and if you want to replace the Nulls to zeros add:
df1 = df1.fillna(0)
Here is another way using combine_first()
i = ['Month','TempBin']
df2.set_index(i).combine_first(df1.set_index(i)).reset_index()

plan shapes issue in dataframe concat

i'm trying to concat dataframe df
to dataframe df_train
in each iteration
since i do not know the categories of df in advance i'm having hard time achieving the desired result as shown below
I have tried many approaches including
df_train = pd.concat([df_train,df],axis=0,ignore_index=True,sort=False)
or
df_train = df_train.append(df,sort=False)
However i'm getting
ValueError: Plan shapes are not aligned
Not sure what i'm doing wrong. Any help would be much appreciated.
Update: This issue exist only when i convert my categorical data to numerical with
df = pd.get_dummies(df,prefix_sep='', prefix='')
however
df=pd.get_dummies(df) #does not pose same issue
reproducing your image data:
df = pd.DataFrame([
[1,0,23,0,0,1,0],
[1,1,65,0,1,0,1],
[4,2,34,1,0,0,0]
], columns=['Iteration', 'Player', 'Result', 'cat1', 'cat2', 'cat3', 'cat4'])
df_train = pd.DataFrame([
[2,54,0,0,0,1,0],
[2,87,1,0,1,0,1],
[2,78,2,1,0,0,0]
], columns=['Iteration','Result','Player', 'cat3', 'cat1', 'cat9', 'cat8'])
df.head()
Iteration Player Result cat1 cat2 cat3 cat4
0 1 0 23 0 0 1 0
1 1 1 65 0 1 0 1
2 4 2 34 1 0 0 0
df_train.head()
Result Player cat3 cat1 cat9 cat8
0 2 54 0 0 0 1 0
1 2 87 1 0 1 0 1
2 2 78 2 1 0 0 0
Now, apply the merge
df3 = df_train.merge(df, how = 'outer', on = ['Iteration','Player','Result'])
Out:
Iteration Player Result cat1 cat2 cat3 cat4 cat9 cat8
0 1 0 23 0 0.0 1 0.0 NaN NaN
1 1 1 65 0 1.0 0 1.0 NaN NaN
2 4 2 34 1 0.0 0 0.0 NaN NaN
3 2 0 54 0 NaN 0 NaN 1.0 0.0
4 2 1 87 1 NaN 0 NaN 0.0 1.0

Reindexing after a pivot in pandas

Consider the following dataset:
After running the code:
convert_dummy1 = convert_dummy.pivot(index='Product_Code', columns='Month', values='Sales').reset_index()
The data is in the right form, but my index column is named 'Month', and I cannot seem to remove this at all. I have tried codes such as the below, but it does not do anything.
del convert_dummy1.index.name
I can save the dataset to a csv, delete the ID column, and then read the csv - but there must be a more efficient way.
Dataset after reset_index():
convert_dummy1
Month Product_Code 0 1 2 3 4
0 10133.9 0 0 0 0 0
1 10146.9 120 80 60 0 100
convert_dummy1.index = pd.RangeIndex(len(convert_dummy1.index))
del convert_dummy1.columns.name
convert_dummy1
Product_Code 0 1 2 3 4
0 10133.9 0 0 0 0 0
1 10146.9 120 80 60 0 100
Since you pivot with columns="Month", each column in output corresponds to a month. If you decide to reset index after the pivot, you should check column names with convert_dummy1.columns.value which should return in your case :
array(['Product_Code', 1, 2, 3, 4, 5], dtype=object)
while convert_dummy1.columns.names should return:
FrozenList(['Month'])
So to rename Month, use rename_axis function:
convert_dummy1.rename_axis('index',axis=1)
Output:
index Product_Code 1 2 3 4 5
0 10133 NaN NaN NaN NaN 0.0
1 10234 NaN 0.0 NaN NaN NaN
2 10245 0.0 NaN NaN NaN NaN
3 10345 NaN NaN NaN 0.0 NaN
4 10987 NaN NaN 1.0 NaN NaN
If you wish to reproduce it, this is my code:
df1=pd.DataFrame({'Product_Code':[10133,10245,10234,10987,10345], 'Month': [1,2,3,4,5], 'Sales': [0,0,0,1,0]})
df2=df1.pivot_table(index='Product_Code', columns='Month', values='Sales').reset_index().rename_axis('index',axis=1)

Use Pandas dataframe to add lag feature from MultiIindex Series

I have a MultiIndex Series (3 indices) that looks like this:
Week ID_1 ID_2
3 26 1182 39.0
4767 42.0
31393 20.0
31690 42.0
32962 3.0
....................................
I also have a dataframe df which contains all the columns (and more) used for indices in the Series above, and I want to create a new column in my dataframe df that contains the value matching the ID_1 and ID_2 and the Week - 2 from the Series.
For example, for the row in dataframe that has ID_1 = 26, ID_2 = 1182 and Week = 3, I want to match the value in the Series indexed by ID_1 = 26, ID_2 = 1182 and Week = 1 (3-2) and put it on that row in a new column. Further, my Series might not necessarily have the value required by the dataframe, in which case I'd like to just have 0.
Right now, I am trying to do this by using:
[multiindex_series.get((x[1].get('week', 2) - 2, x[1].get('ID_1', 0), x[1].get('ID_2', 0))) for x in df.iterrows()]
This however is very slow and memory hungry and I was wondering what are some better ways to do this.
FWIW, the Series was created using
saved_groupby = df.groupby(['Week', 'ID_1', 'ID_2'])['Target'].median()
and I'm willing to do it a different way if better paths exist to create what I'm looking for.
Increase the Week by 2:
saved_groupby = df.groupby(['Week', 'ID_1', 'ID_2'])['Target'].median()
saved_groupby = saved_groupby.reset_index()
saved_groupby['Week'] = saved_groupby['Week'] + 2
and then merge df with saved_groupby:
result = pd.merge(df, saved_groupby, on=['Week', 'ID_1', 'ID_2'], how='left')
This will augment df with the target median from 2 weeks ago.
To make the median (target) saved_groupby column 0 when there is no match, use fillna to change NaNs to 0:
result['Median'] = result['Median'].fillna(0)
For example,
import numpy as np
import pandas as pd
np.random.seed(2016)
df = pd.DataFrame(np.random.randint(5, size=(20,5)),
columns=['Week', 'ID_1', 'ID_2', 'Target', 'Foo'])
saved_groupby = df.groupby(['Week', 'ID_1', 'ID_2'])['Target'].median()
saved_groupby = saved_groupby.reset_index()
saved_groupby['Week'] = saved_groupby['Week'] + 2
saved_groupby = saved_groupby.rename(columns={'Target':'Median'})
result = pd.merge(df, saved_groupby, on=['Week', 'ID_1', 'ID_2'], how='left')
result['Median'] = result['Median'].fillna(0)
print(result)
yields
Week ID_1 ID_2 Target Foo Median
0 3 2 3 4 2 0.0
1 3 3 0 3 4 0.0
2 4 3 0 1 2 0.0
3 3 4 1 1 1 0.0
4 2 4 2 0 3 2.0
5 1 0 1 4 4 0.0
6 2 3 4 0 0 0.0
7 4 0 0 2 3 0.0
8 3 4 3 2 2 0.0
9 2 2 4 0 1 0.0
10 2 0 4 4 2 0.0
11 1 1 3 0 0 0.0
12 0 1 0 2 0 0.0
13 4 0 4 0 3 4.0
14 1 2 1 3 1 0.0
15 3 0 1 3 4 2.0
16 0 4 2 2 4 0.0
17 1 1 4 4 2 0.0
18 4 1 0 3 0 0.0
19 1 0 1 0 0 0.0

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