Category: Python Answers

Sometimes, we want to count the frequency of the elements in an unordered list with Python.

In this article, we’ll look at how to count the frequency of the elements in an unordered list with Python.

How to count the frequency of the elements in an unordered list with Python?

To count the frequency of the elements in an unordered list with Python, we can use the collections.Counter class.

For instance, we write

import collections

a = [1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 4, 5, 5]
counter = collections.Counter(a)

to call Counter with a to return a dictionary with the values in a as keys and the count of each item in a as the values.

Conclusion

To count the frequency of the elements in an unordered list with Python, we can use the collections.Counter class.

Sometimes, we want to run a Python file in another Python file.

In this article, we’ll look at how to run a Python file in another Python file.

How to run a Python file in another Python file?

To run a Python file in another Python file, we can use the subprocess.call method.

For instance, we write

from subprocess import call

call(["python", "your_file.py"])

to call call with a list with the command and arguments to run the your_file.py Python script in the same directory as the current script.

Conclusion

To run a Python file in another Python file, we can use the subprocess.call method.

Sometimes, we want to convert a Unicode string that contains extra symbols to a string in Python.

In this article, we’ll look at how to convert a Unicode string that contains extra symbols to a string in Python.

How to convert a Unicode string that contains extra symbols to a string in Python?

To convert a Unicode string that contains extra symbols to a string in Python, we can use the encode methods.

For instance, we write

a = u"aaaàçççñññ"
b = a.encode("ascii", "ignore")

to call a.encode with 'ascii' and 'ignore' to encode the string a as an ASCII string.

And we call it with 'ignore' to discard any characters that aren’t in the ASCII character set.

Conclusion

To convert a Unicode string that contains extra symbols to a string in Python, we can use the encode methods.

Sometimes, we want to fix "datetime.datetime not JSON serializable" with Python.

In this article, we’ll look at how to fix "datetime.datetime not JSON serializable" with Python.

How to fix "datetime.datetime not JSON serializable" with Python?

To fix "datetime.datetime not JSON serializable" with Python, we can use the json.dumps method with the default argument set to str.

For instance, we write

s = json.dumps(my_dictionary, indent=4, sort_keys=True, default=str)

to serialize the my_dictionary dict to a JSON string by calling it with the default argument set to str.

This will convert anything that’s not serializable to a string, including datetime objects.

Conclusion

To fix "datetime.datetime not JSON serializable" with Python, we can use the json.dumps method with the default argument set to str.

Sometimes, we want to write a list to a file with Python.

In this article, we’ll look at how to write a list to a file with Python.

How to write a list to a file with Python?

To write a list to a file with Python, we can use a loop.

For instance, we write

with open("your_file.txt", "w") as f:
    for item in my_list:
        f.write("%s\n" % item)

to open your_file.txt with open with write permission.

Then we use a for loop to loop through my_list and write the item in the list to the file with f.write.

Conclusion

To write a list to a file with Python, we can use a loop.