Develop Reference

Converting Datetimeindex of a dataframe to week numbers

I am very new to Python and cannot seem to solve the problem on my own. Currently I have a dataset which I already converted to a DataFrame using pandas which has a datetimeindex according to yyyy-mm-dd-HH-MM-SS with time stamps of minutes. The attached figure shows the already interpolated dataframe.
enter image description here
Now I want to convert the date/datetimeindex to week numbers to plot the corresponding HVAC Actual, Chiller power etc. to their week number. The index already was set to time but I got an error telling that 'Time' was not recognized in the columns. I tried to recall the index like in the code below and from there create a new column using dt.week
building_interpolated = building_interpolated.set_index('Time')
building_interpolated['Week number'] =
building_interpolated['Time'].dt.week
If I am correct this should create a new column called Week number with the week number in it. However, I still get an error telling that ['Time'] is not in the columns (see figure below)
enter image description here
Anyone who can help me?
Regards, nooby Boaz ;)

df.index = df.index.to_series().dt.isocalendar().week

Pandas Data frames and sorting values

I am having a difficult time with writing this hw assignment, and am not sure where I messed up. I have tried several things, and believe my issue lies in the sort_values or maybe in the groupby command.
The issue is that I want to only display graph data from the year 2007. (using pandas and plotly in jupyternotebook for my class). I have the graph I want mostly but cannot get it to display the data correctly. It simply isn't filtering out the years, or taking data from specific dates as requested.
import pandas as pd
import plotly.express as px
df = pd.read_csv('Data/Country_Data.csv')
print(df.shape)
df.head(2)
df_Q1 = df.query("year == '2007'")
print(df_Q1.shape)
df_Q1.head()
This is where the issue begins, because it prints a table with only header information. As in it prints all the column names, but none of the data for them, and then later on it displays a graph of what I assume is the most recent death data rather than the year 2007 as specified.

Why does not Seaborn Relplot print datetime value on x-axis?

I'm trying to solve a Kaggle Competition to get deeper into data science knowledge. I'm dealing with an issue with seaborn library. I'm trying to plot a distribution of a feature along the date but the relplot function is not able to print the datetime value. On the output, I see a big black box instead of values.
Here there is my code, for plotting:
rainfall_types = list(auser.loc[:,1:])
grid = sns.relplot(x='Date', y=rainfall_types[0], kind="line", data=auser);
grid.fig.autofmt_xdate()
Here there is the
Seaborn.relpot output and the head of my dataset

I found the error. Pratically, when you use pandas.read_csv(dataset), if your dataset contains datetime column they are parsed as object, but python read these values as 'str' (string). So when you are going to plot them, matplotlib is not able to show them correctly.
To avoid this behaviour, you should convert the datetime value into datetime object by using:
df = pandas.read_csv(dataset, parse_date='Column_Date')
In this way, we are going to indicate to pandas library that there is a date column identified by the key 'Column_Date' and it has to be converted into datetime object.
If you want, you could use the Column Date as index for your dataframe, to speed up the analyis along the time. To do it add argument index='Column_Date' at your read_csv.
I hope you will find it helpful.

How can I grab the date from the top of this csv?

Hi! I have this csv I'm trying to grab the date from using pandas. the date is located above the header in the picture above. I thought I could just grab row 3 but that doesn't seem to work. Here is my code. My goal is to convert that date into datetime so I can recognize what day I'm grabbing info from. The name of the csv unfortunately has the wrong date.
datetime_df = pd.read_csv(holdings_file)
print(datetime_df.row(3))
AttributeError: 'DataFrame' object has no attribute 'row'

To get a value at a certain cell in a dataframe, you need to use iat rather than row. Also, if you want that date, you want the 3rd column not the 3rd row.
datetime_df = pd.read_csv(holdings_file)
print(datetime_df.iat[0,3])

Exporting Pandas DataFrame cells directly to excel/csv (python)

I have a Pandas DataFrame that has sports records in it. All of them look like this: "1-2-0", "17-12-1", etc., for wins, losses and ties. When I export this the records come up in different date formats within Excel. Some will come up as "12-May", others as "9/5/2001", and others will come up as I want them to.
The DataFrame that I want to export is named 'x' and this is the command I'm currently using. I tried it without the date_format part and it gave the same response in Excel.
x.to_csv(r'C:\Users\B\Desktop\nba.csv', date_format = '%s')
Also tried using to_excel and I kept getting errors while trying to export. Any ideas? I was thinking I am doing the date_format part wrong, but don't know to transfer the string of text directly instead of it getting automatically switched to a string.
Thanks!

I don't think its a python issue, but Excel auto detecting dates in your data.
But, see below to convert your scores to strings.
Try this,
import pandas as pd
df = pd.DataFrame({"lakers" : ["10-0-1"],"celtics" : ["11-1-3"]})
print(df.head())
here is the dataframe with made up data.
lakers celtics
0 10-0-1 11-1-3
Convert to dataframe to string
df = df.astype(str)
and save the csv:
df.to_csv('nba.csv')
Opening in LibreOffice gives me to columns with scores (made up)
You might have a use Excel issue going on here. Inline with my comment below, you can change any column in Excel to lots of different formats. In this case I believe Excel is auto detecting date formatting, incorrectly. Select your columns of data, right click, select format and change to anything else, like 'General'.