CODEWITHSUNDEEP
pythoncsvpandasmatplotlib
rushan
rushan

Reputation: 221

How to plot CSV data

I have a python code in which I read a csv file using pandas and store date and time in one column Datetime. Now i want to plot Sensor Value on y-axis and datatime on x-axis. How can i achieve this? My code is below: 

import pandas as pd
import datetime
import csv
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
headers = ['Sensor Value','Date','Time']
df = pd.read_csv('C:/Users\Lala Rushan\Downloads\DataLog.CSV',parse_dates=     {"Datetime" : [1,2]},names=headers)
print (df)

Heres some rows from dataset: 

                      Datetime  Sensor Value
0     2017/02/17  19:06:17.188             2
1     2017/02/17  19:06:22.360            72
2     2017/02/17  19:06:27.348            72
3     2017/02/17  19:06:32.482            72
4     2017/02/17  19:06:37.515            74
5     2017/02/17  19:06:42.580            70
6     2017/02/17  19:06:47.660            72

Upvotes: 13

Views: 91679

Answers (3)

Roy
Roy

Reputation: 29

Updated solution for Python 3.9 with date in the format '2022-01-11 23:57' :

import pandas as pd
import matplotlib.pyplot as plt

df = pd.read_csv('data.csv')

df['Datetime'] = pd.to_datetime(df['Datetime'], format='%m/%d/%Y %H:%M')

# plot the dataframe directly
ax = df.plot(x='Datetime', y='Sensor Value')

# beautify the x-labels
ax.autofmt_xdate()

plt.show()

Or plot with pyplot directly

fig, ax = plt.subplots()

ax.plt('Datetime', 'Sensor Value', data=df)
ax.autofmt_xdate()

Upvotes: 1

PyUser2222
PyUser2222

Reputation: 1

To get this code to work on the machine I'm currently coding on (MacOS 10.14) with Python 2.7.16, I needed to declare the row of the CSV file that the headers are on. So this is a header=1 in the read_csv section, as is recommended on the official pandas read_csv page here .

My code is below:

import pandas as pd
from datetime import datetime
import csv
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
headers = ['sensor_data','Date']
df = pd.read_csv('output.csv',header=1,names=headers)

df['Date']= pd.to_datetime(df['Date'], format='%Y-%m-%d %H:%M:%S')

df['Date']= df['Date'].map(lambda x: datetime.strptime(str(x), '%Y-%m-%d %H:%M:%S'))

x = df['Date']
print(x)
y = df['sensor_data']

# plot
plt.plot(x,y)
# beautify the x-labels
plt.gcf().autofmt_xdate()

plt.show()

Upvotes: 0

Rohan
Rohan

Reputation: 5431

Make sure your date column is in datetime format and use plot() function in matplotlib. You could do something similar to this. Here x-value will be your date column and y value will be sensor value.

import pandas as pd
from datetime import datetime
import csv
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
headers = ['Sensor Value','Date','Time']
df = pd.read_csv('C:/Users\Lala Rushan\Downloads\DataLog.CSV',names=headers)
print (df)

df['Date'] = df['Date'].map(lambda x: datetime.strptime(str(x), '%Y/%m/%d %H:%M:%S.%f'))
x = df['Date']
y = df['Sensor Value']

# plot
plt.plot(x,y)
# beautify the x-labels
plt.gcf().autofmt_xdate()

plt.show()

enter image description here

Upvotes: 27

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