I'm working on a data frame taken from Adafruit IO and sadly some of my data is from a time when my project malfunctioned so some of the values are just equal NaN.
I tried to remove it by typing this code lines:
onlyValidData=temp_data.mask(temp_data['value'] =='NaN')
onlyValidData
This is data retreived from Adafruit IO Feed, getting analyzed by pandas, I tried using 'where' function too but it didn't work
my entire code is
import pandas as pd
temp_data = pd.read_json('https://io.adafruit.com/api/(...)')
light_data = pd.read_json('https://io.adafruit.com/api/(...)')
temp_data['created_at'] = pd.to_datetime(temp_data['created_at'], infer_datetime_format=True)
temp_data = temp_data.set_index('created_at')
light_data['created_at'] = pd.to_datetime(light_data['created_at'], infer_datetime_format=True)
light_data = light_data.set_index('created_at')
tempVals = pd.Series(temp_data['value'])
lightVals = pd.Series(light_data['value'])
onlyValidData=temp_data.mask(temp_data['value'] =='NaN')
onlyValidData
The output is all of my data for some reason, but it should be only the valid values.
Hey I think the issue here that you're looking for values equal to the string 'NaN', while actual NaN values aren't a string, or more specifically aren't anything.
Try using:
onlyValidData = temp_data.mask(temp_data['value'].isnull())
Edit: to remove rows rather than marking all values in that row as NaN:
onlyValidData = temp_data.dropna()
Related
I am trying to split the time_taken attribute (eg., 02h 10m) into only numbers using the below code.
I have checked earlier posts and this code seemed to work fine for some of you but it is not working for me.
t=pd.to_timedelta(df3['time_taken'])
df3['hours']=t.dt.components['hours']
df3['minutes']=t.dt.components['minutes']
df3.head()
I am getting the following error:
ValueError: invalid unit abbreviation: hm
I am unable to understand the error. Can anyone help me split the column into hours and mins? It would be of great help. Thanks in advance.
You can try this code. Since you mentioned that your time_taken attribute looks like this: 02h 10m. I have written an example code which you can try out.
import pandas as pd
# initializing example time data
time_taken = ['1h 10m', '2h 20m', '3h 30m', '4h 40m', '5h 50m']
#inserting the time data into a pandas DataFrame
data = pd.DataFrame(time_taken, columns = ['time_taken'])
# see how the data looks like
print(data)
# initializing "Hours" and "Minutes" columns"
# and assigning the value 0 to both for now.
data['Hours'] = 0
data['Minutes'] = 0
# when I ran this code, the data type for the elements
# in time_taken column was numpy.int64
# so we convert it into string type
data['time_taken'] = data['time_taken'].apply(str)
# loop through the elements to split into Hours and minutes
for i in range(len(data)):
temp = data.iat[i,0]
hours, minutes = temp.split() # use python .split() function for strings
data.iat[i,1] = hours.translate({ord('h'): None})
data.iat[i,2] = minutes.translate({ord('m'): None})
# the correct data is here
print(data)
I am a very beginner in programming and trying to learn to code. so please bear with my bad coding. I am using pandas to find a string from a column (Combinations column in the below code ) in the data frame and print the entire row containing the string . Find the code below. Basically I need to find all the instances where the string occurs , and print the entire row .find my code below . I am not able to figure out how to find that particular instance of the column and print it .
import pandas as pd
data = pd.read_csv("signallervalues.csv",index_col=False)
data.head()
data['col1'] = data['col1'].astype(str)
data['col2'] = data['col2'].astype(str)
data['col3'] = data['col3'].astype(str)
data['col4'] = data['col4'].astype(str)
data['col5']= data['col5'].astype(str)
data.head()
combinations= data['Col1']+data['col2'] + data['col3'] + data['col4'] + data['col5']
data['combinations']= combinations
print(data.head())
list_of_combinations = data['combinations'].to_list()
print(list_of_combinations)
for i in list_of_combinations:
if data['combinations'].str.contains(i).any():
print(i+ 'data occurs in row' )
# I need to print the row containing the string here
else:
print(i +'is occuring only once')
my data frame looks like this
import pandas as pd
data=pd.DataFrame()
# recreating your data (more or less)
data['signaller']= pd.Series(['ciao', 'ciao', 'ciao'])
data['col6']= pd.Series(['-1-11-11', '11', '-1-11-11'])
list_of_combinations=['11', '-1-11-11']
data.reset_index(inplace=True)
# group by the values of column 6 and counting how many times they occur
g=data.groupby('col6')['index']
count= pd.DataFrame(g.count())
count=count.rename(columns={'index':'occurences'})
count.reset_index(inplace=True)
# create a df that keeps only the rows in the list 'list_of_combinations'
count[~count['col6'].isin(list_of_combinations)== False]
My result
I am having a hard time summing two dates that are saved in two separate json files. I want to add set dates together which are saved in separate libraries.
The first file (A1.json) contains: {"expires": "2019-09-11"}
The second file (Whitelist.json) contains: {"expires": "0000-01-00"}
These dates are created by using tkcalendar and are later exported to these seperate files, the idea being that summing them lets me set a time date one month into the future. However, I can't seem to add them together without some form of an error.
I have tried converting the json files to strings in python and then adding them and also using the striptime command to sum the dates.
Here is the relevant chunk of the code:
{with open('A1.json') as f:
data=json.loads(f.read())
for material in data.items():
A1 = (format(material[1]['expires']))
with open('Whitelist.json') as f:
data=json.loads(f.read())
for material in data.items():
A2 = (format(material[1]['expires']))
print(A1+A2)}
When this is used, they just get pasted one after another. They don't get summed the way I need.
I also have tried the following code:
{t1 = dt.datetime.strptime('A1', '%d-%m-%Y')
t2 = dt.datetime.strptime('Whitelist', '%d-%m-%Y')
time_zero = dt.datetime.strptime('00:00:00', '%d/%m/%Y')
print((t1 - time_zero + Whitelist).time())}
However, this constantly gives out ValueError: time data does not match format '%y:%m:%d'.
What I expect is the sum of 2019-09-11 and 0000-01-00's result is 2019-10-11. However, the result is 2019-09-110000-01-00. Trying the strptime method gives out ValueErrors such as: ValueError: time data does not match format '%y:%m:%d'.
Thank you in advance, and I apologize if I did something wrong on my first post.
Use pandas:
the actual format of the json file isn't provided, so use something like the following to get the data into a DataFrame:
pd.read_json('A1.json', orient='records'): parameters will depend on the format of the file
json_normalize
d2 is not a proper datetime format so don't try to convert it.
the Code section below, will use a dict to set up the DataFrame for the example.
json files to DataFrames:
df1 = pd.read_json('A1.json', orient='records')
df2 = pd.read_json('Whitelist.json', orient='records')
df = pd.DataFrame()
df['expires'] = df1.expires
df['d2'] = df2.expires
Code:
import pandas as pd
df = pd.DataFrame({"expires": ["2019-09-11", "2019-10-11", "2019-11-11"],
"d2": ["0000-01-00", "0000-02-00", "0000-03-00"]})
Expand d2 using str.split:
df.expires = pd.to_datetime(df.expires)
df[['y', 'm', 'd']] = df.d2.str.split('-', expand=True)
Use pd.DateOffset:
df['expires_new'] = df[['expires', 'm']].apply(lambda x: x[0] + pd.DateOffset(months=int(x[1])), axis=1)
if d2 is expected to have more than just a new m or month value, the lambda expression can be changed to call a function that adjusts for y, m, and d values.
I have some very noisy (astronomy) data in csv format. Its shape is (815900,2) with 815k points giving information of what the mass of a disk is at a certain time. The fluctuations are pretty noticeable when you look at it close up. For example, here is an snippet of the data where the first column is time in seconds and the second is mass in kg:
40023700,2.40896E+028
40145700,2.44487E+028
40267700,2.44487E+028
40389700,2.44478E+028
40511600,1.535E+028
40633500,2.19067E+028
40755400,2.44496E+028
40877200,2.44489E+028
40999000,2.44489E+028
41120800,2.34767E+028
41242600,2.40936E+028
So it looks like there is a 1.53E+028 data point of noise, and also probably the 2.19E+028 and 2.35E+028 points.
To fix this, I am trying to set a Python script that will read in the csv data, then put some restriction on it so that if the mass is e.g. < 2.35E+028, it will remove the whole row and then create a new csv file with only the "good" data points:
40023700,2.40896E+028
40145700,2.44487E+028
40267700,2.44487E+028
40389700,2.44478E+028
40755400,2.44496E+028
40877200,2.44489E+028
40999000,2.44489E+028
41242600,2.40936E+028
Following this old question top answer by n8henrie, I so far have:
import pandas as pd
import csv
# Here are the locations of my csv file of my original data and an EMPTY csv file that will contain my good, noiseless set of data
originaldata = '/Users/myname/anaconda2/originaldata.csv'
gooddata = '/Users/myname/anaconda2/gooddata.csv'
# I use pandas to read in the original data because then I can separate the columns of time as 'T' and mass as 'M'
originaldata = pd.read_csv('originaldata.csv',delimiter=',',header=None,names=['t','m'])
# Numerical values of the mass values
M = originaldata['m'].values
# Now to put a restriction in
for row in M:
new_row = []
for column in row:
if column > 2.35E+028:
new_row.append(column)
csv.writer(open(newfile,'a')).writerow(new_row)
print('\n\n')
print('After:')
print(open(newfile).read())
However, when I run this, I get this error:
TypeError: 'numpy.float64' object is not iterable
I know the first column (time) is dtype int64 and the second column (mass) is dtype float64... but as a beginner, I'm still not quite sure what this error means or where I'm going wrong. Any help at all would be appreciated. Thank you very much in advance.
You can select rows by a boolean operation. Example:
import pandas as pd
from io import StringIO
data = StringIO('''\
40023700,2.40896E+028
40145700,2.44487E+028
40267700,2.44487E+028
40389700,2.44478E+028
40511600,1.535E+028
40633500,2.19067E+028
40755400,2.44496E+028
40877200,2.44489E+028
40999000,2.44489E+028
41120800,2.34767E+028
41242600,2.40936E+028
''')
df = pd.read_csv(data,names=['t','m'])
good = df[df.m > 2.35e+28]
out = StringIO()
good.to_csv(out,index=False,header=False)
print(out.getvalue())
Output:
40023700,2.40896e+28
40145700,2.44487e+28
40267700,2.44487e+28
40389700,2.44478e+28
40755400,2.44496e+28
40877200,2.44489e+28
40999000,2.44489e+28
41242600,2.40936e+28
This returns a column: M = originaldata['m'].values
So when you do for row in M:, you get only one value in row, so you can't iterate on it again.
I've pulled some stock data from Quandl for both Crude Oil prices (WTI) and Caterpillar (CAT) price. When I concatenate the two dataframes together I'm left with some NaNs. My ultimate goal is to run a .Pearsonr() to assess the correlation (along with p-values), however I can't get Pearsonr() to work because of all the Nan's. So I'm trying to clean them up. When I use the .fillNA() function it doesn't seem to be working. I've even tried .interpolate() as well as .dropna(). None of them appear to work. Here is my working code.
import Quandl
import pandas as pd
import numpy as np
#WTI Data#
WTI_daily = Quandl.get("DOE/RWTC", collapse="daily",trim_start="1986-10-10", trim_end="1986-10-15")
WTI_daily.columns = ['WTI']
#CAT Data
CAT_daily = Quandl.get("YAHOO/CAT.6", collapse = "daily",trim_start="1986-10-10", trim_end="1986-10-15")
CAT_daily.columns = ['CAT']
#Combine Data Frames
daily_price_df = pd.concat([CAT_daily, WTI_daily], axis=1)
print daily_price_df
#Verify they are dataFrames:
def really_a_df(var):
if isinstance(var, pd.DataFrame):
print "DATAFRAME SUCCESS"
else:
print "Wahh Wahh"
return 'done'
print really_a_df(daily_price_df)
#Fill NAs
#CAN'T GET THIS TO WORK!!
daily_price_df.fillna(method='pad', limit=8)
print daily_price_df
# Try to interpolate
#CAN'T GET THIS TO WORK!!
daily_price_df.interpolate()
print daily_price_df
#Drop NAs
#CAN'T GET THIS TO WORK!!
daily_price_df.dropna(axis=1)
print daily_price_df
For what it's worth I've managed to get the function working when I create a dataframe from scratch using this code:
import pandas as pd
import numpy as np
d = {'a' : 0., 'b' : 1., 'c' : 2.,'d':None,'e':6}
d_series = pd.Series(d, index=['a', 'b', 'c', 'd','e'])
d_df = pd.DataFrame(d_series)
d_df = d_df.fillna(method='pad')
print d_df
Initially I was thinking that perhaps my data wasn't in dataframe form, but I used a simple test to confirm they are in fact dataframe. The only conclusion I that remains (in my opinion) is that it is something about the structure of the Quandl dataframe, or possibly the TimeSeries nature. Please know I'm somewhat new to python so structure answers for a begginner/novice. Any help is much appreciated!
pot shot - have you just forgotten to assign or use the inplace flag.
daily_price_df = daily_price_df.fillna(method='pad', limit=8)
OR
daily_price_df.fillna(method='pad', limit=8, inplace=True)