Category: Python

Sometimes, we want to find all occurrences of an element in a list with Python.

In this article, we’ll look at how to find all occurrences of an element in a list with Python.

How to find all occurrences of an element in a list with Python?

To find all occurrences of an element in a list with Python, we can use list comprehension.

For instance, we write:

l = [1, 2, 3, 4, 3, 2, 5, 6, 7]
indexes = [i for i, val in enumerate(l) if val == 3]
print(indexes)

We use enumerate to return an iterator with the tuples for the index and value of each l array entry.

Then we get the i index of each entry if their value is 3 by using the condition val == 3.

And then we assign the array of indexes of the l array where its values is 3 to indexes.

Therefore, indexes is [2, 4].

Conclusion

To find all occurrences of an element in a list with Python, we can use list comprehension.

Sometimes, we want to copy a dictionary and only edit the copy with Python.

In this article, we’ll look at how to copy a dictionary and only edit the copy with Python.

How to copy a dictionary and only edit the copy with Python?

To copy a dictionary and only edit the copy with Python, we can use the dict function or the dictionary’s copy method.

For instance, we write:

dict1 = {'a': 1, 'b': 2}

c1 = dict(dict1)
c2 = dict1.copy()

print(c1)
print(c2)

to call dict with dict1 to return a copy of dict1.

Likewise, we call dict1.copy to return a copy of dict1.

Therefore, c1 and c2 are both {'a': 1, 'b': 2}.

Conclusion

To copy a dictionary and only edit the copy with Python, we can use the dict function or the dictionary’s copy method.

Sometimes, we want to strip punctuation from a string with Python.

In this article, we’ll look at how to strip punctuation from a string with Python.

How to strip punctuation from a string with Python?

To strip punctuation from a string with Python, we can use the string’s translate method.

For instance, we can write:

import string

s = 'hello world!!!'
new_s = s.translate(str.maketrans('', '', string.punctuation))
print(new_s)

to call s.translate with str.maketrans('', '', string.punctuation) to return a new string without the punctuation characters in it.

Then we assign that to new_s.

Therefore, new_s is 'hello world'.

Conclusion

To strip punctuation from a string with Python, we can use the string’s translate method.

Sometimes, we want to get the full path of the current file’s directory with Python.

In this article, we’ll look at how to get the full path of the current file’s directory with Python.

How to get the full path of the current file’s directory with Python?

To get the full path of the current file’s directory with Python, we can use the pathlib module.

For instance, we write:

import pathlib

curr_path = pathlib.Path(__file__).parent.resolve()
print(curr_path)

We use the pathlib.Path constructor with __file__ to create a Path instance from the current script file.

Then we call parent.resolve to return the current path of the file and assign that to curr_path.

Therefore, curr_path is something like '/home/runner/GrandPoorField'.

Conclusion

To get the full path of the current file’s directory with Python, we can use the pathlib module.

Sometimes, we want to get file creation and modification date and times in Python.

In this article, we’ll look at how to get file creation and modification date and times in Python.

How to get file creation and modification date and times in Python?

To get file creation and modification date and times in Python, we can use the os.path.getctime and os.path.getmtime methods respectively.

For instance, we write:

import os.path, time

file = './bar.txt'
print("last modified: %s" % time.ctime(os.path.getmtime(file)))
print("created: %s" % time.ctime(os.path.getctime(file)))

We call time.ctime with os.path.getmtime to convert the Unix timestamp of the modification date and time of the file to a human readable date and time string.

Likewise, we call time.ctime with os.path.getctime to convert the Unix timestamp of the creation date and time of the file to a human readable date and time string.

Therefore, we should see something like:

last modified: Sun Oct 17 17:45:30 2021
created: Sun Oct 17 17:50:44 2021

printed from the print calls.

Conclusion

To get file creation and modification date and times in Python, we can use the os.path.getctime and os.path.getmtime methods respectively.