Category: Python

Sometimes, we want to ignore the first line of data when processing CSV data with Python.

In this article, we’ll look at how to ignore the first line of data when processing CSV data with Python.

How to ignore the first line of data when processing CSV data with Python?

To ignore the first line of data when processing CSV data with Python, we can call next to skip to the next row.

For instance, if we have:

test.csv

col1,col2
1,2
3,4
5,6

Then we write:

import csv
with open('test.csv') as f:
    f_csv = csv.reader(f)
    headers = next(f_csv)
    for row in f_csv:
        print(row)

to open the test.csv with open.

Then we call csv.reader with f to read the file.

Next, we skip the first row by calling next with f_csv.

The first row’s data is returned with next and assigned to headers.

And finally, we loop through the rest of the rows with a for loop and print each row.

Therefore, we see:

['1', '2']
['3', '4']
['5', '6']

printed.

Conclusion

To ignore the first line of data when processing CSV data with Python, we can call next to skip to the next row.

Sometimes, we want to get number closest to a given value from a list of integers with Python.

In this article, we’ll look at how to get number closest to a given value from a list of integers with Python.

How to get number closest to a given value from a list of integers with Python?

To get number closest to a given value from a list of integers with Python, we can use the min function with the key parameter set to a function that returns the absolute difference between the value and the number in the list.

For instance, we write:

my_num = 100
l = [29, 58, 129, 487, 41]
closest = min(l, key=lambda x: abs(x - my_num))
print(closest)

We have my_num which is the number we want to get the closest value to from the list l.

To do that, we call min with l and key set to lambda x: abs(x - my_num)).

lambda x: abs(x - my_num)) returns the absolute difference between x which is an entry in l and my_num.

And then we assign the returned number to closest.

Therefore, closest is 129.

Conclusion

To get number closest to a given value from a list of integers with Python, we can use the min function with the key parameter set to a function that returns the absolute difference between the value and the number in the list.

Sometimes, we want to generate random numbers with a given (numerical) distribution with Python.

In this article, we’ll look at how to generate random numbers with a given (numerical) distribution with Python.

How to generate random numbers with a given (numerical) distribution with Python?

To generate random numbers with a given (numerical) distribution with Python, we can use the choice function from the random module.

For instance, we write:

from random import choices

population = [1, 2, 3, 4, 5, 6]
weights = [0.1, 0.05, 0.05, 0.2, 0.4, 0.2]
num = choices(population, weights)
print(num)

We call choices with the population list which we draw numbers from and the weights list which are numerical distribution of each value.

The returned number is assigned to num.

Conclusion

To generate random numbers with a given (numerical) distribution with Python, we can use the choice function from the random module.

Sometimes, we want to convert Python datetime to epoch with strftime.

In this article, we’ll look at how to convert Python datetime to epoch with strftime.

How to convert Python datetime to epoch with strftime?

To convert Python datetime to epoch with strftime, we can call the timestamp method.

For instance, we write:

import datetime

t = datetime.datetime(2020, 4, 1, 0, 0).timestamp()
print(t)

We call timestamp on the datetime object and assign the returned timestamp to t.

Therefore, t is 1585699200.0.

Conclusion

To convert Python datetime to epoch with strftime, we can call the timestamp method.

Sometimes, we want to replace multiple characters in a string with Python.

In this article, we’ll look at how to replace multiple characters in a string with Python.

How to replace multiple characters in a string with Python?

To replace multiple characters in a string with Python, we can chain the string replace method.

For instance, we write:

strs = "abc&def#ghi"
s = strs.replace('&', '\&').replace('#', '\#')
print(s)

We call strs.replace with '&' and '\&' to replace & and '\&'.

And then we call it again to replace '#' with '\#'.

Finally, we assign the returned string to s.

Therefore, s is 'abc\&def\#ghi'.

Conclusion

To replace multiple characters in a string with Python, we can chain the string replace method.