Author: John Au-Yeung

Sometimes, we want to set default form values with Python Django.

In this article, we’ll look at how to set default form values with Python Django.

How to set default form values with Python Django?

To set default form values with Python Django, we can set the initial argument of the form constructor to a dict with the initial values.

For instance, we write

form = JournalForm(initial={'tank': 123})

to create a JournalForm instance with the initial argument set to {'tank': 123} to set the field with name tank to initial value 123.

Conclusion

To set default form values with Python Django, we can set the initial argument of the form constructor to a dict with the initial values.

Sometimes, we want to find the intersection of multiple sets with Python.

In this article, we’ll look at how to find the intersection of multiple sets with Python.

How to find the intersection of multiple sets with Python?

To find the intersection of multiple sets with Python, we can use the set.intersection method.

For instance, we write

u = set.intersection(*setlist)

to call set.intersection with the sets in the setlist list as arguments.

We use * to get the sets in the list and use them as arguments.

Conclusion

To find the intersection of multiple sets with Python, we can use the set.intersection method.

Sometimes, we want to compare two NumPy arrays for equality, element-wise with Python.

In this article, we’ll look at how to compare two NumPy arrays for equality, element-wise with Python.

How to compare two NumPy arrays for equality, element-wise with Python?

To compare two NumPy arrays for equality, element-wise with Python, we can use the == operator and the all method.

For instance, we write

(A == B).all()

to compare NumPy arrays A and B with == for equality element-wise.

And then we call all to return True if all elements are equal in both arrays and False otherwise.

Conclusion

To compare two NumPy arrays for equality, element-wise with Python, we can use the == operator and the all method.

Sometimes, we want to access an arbitrary element in a dictionary in Python.

In this article, we’ll look at how to access an arbitrary element in a dictionary in Python.

How to access an arbitrary element in a dictionary in Python?

To access an arbitrary element in a dictionary in Python, we can use the values and next functions.

For instance, we write

v = next(iter(mydict.values()))

to get the values from the mydict dict with values.

Then we create an iterator from the the values list with iter.

And then we call next to return the next value returned by the iterator.

Conclusion

To access an arbitrary element in a dictionary in Python, we can use the values and next functions.

Sometimes, we want to use a dictionary to count the items in a list with Python.

In this article, we’ll look at how to use a dictionary to count the items in a list with Python.

How to use a dictionary to count the items in a list with Python?

To use a dictionary to count the items in a list with Python, we can use a for loop.

For instance, we write

counts = dict()
for i in items:
  counts[i] = counts.get(i, 0) + 1

to create a for loop that loops through the items list.

In it, we add an entry to the counts dict which is set to counts.get(i, 0) + 1 to set the count to 1 is the dict entry with key i` not yet exist.

Otherwise, we increment the existing value by 1.

Conclusion

To use a dictionary to count the items in a list with Python, we can use a for loop.