CODEWITHSUNDEEP
python
Annie.hut
Annie.hut

Reputation: 17

How can you delete a value and not a key in a dictionary

so I have to delete 32.32 from the key 'breakfast blend' in my dictionary How can I remove a single value??

print(transaction_dic_11)
for k in list(transaction_dic_11):
    if transaction_dic_11[k] == 32.32:
        del transaction_dic_11[k]

Transaction_dic = {'Classic': [37.33, 46.75, 28.18, 33.35],
                   'breakfast blend':[32.32, 46.94, 26.91, 22.03], 
                   'rev it up': [45.82, 33.89]}`

I tried this code, but it won't delete the value and no changes occur.

Upvotes: 0

Views: 76

Answers (2)

Adon Bilivit
Adon Bilivit

Reputation: 27306

In this particular case you can simply do this:

Transaction_dic['breakfast blend'].remove(32.32)

However, floating point numbers are not always what they seem. You may have to look for values that are "close" to the value using some mechanism of tolerance you will need to devise.

Here's an example of how you might approach this:

def remove_if_near(_list, n, tolerance=0.000001):
    for i, x in enumerate(_list):
        if abs(x - n) < tolerance:
            _list.pop(i)
            break
    return _list

my_list = [1/3, 1/5, 1/9]
print(my_list)
print(remove_if_near(my_list, 0.333333))

Output:

[0.3333333333333333, 0.2, 0.1111111111111111]
[0.2, 0.1111111111111111]

Note:

If the list is sorted then this can be made more efficient. If not sorted then this will potentially be very inefficient for large lists

Upvotes: 0

Dorian Turba
Dorian Turba

Reputation: 3755

transaction_dic_11[k] == 32.32 is ALWAYS false

Because transaction_dic_11[k] value is a list, not a int.

for k in list(transaction_dic_11):
    print(transaction_dic_11[k])
    # [37.33, 46.75, 28.18, 33.35]
    # [32.32, 46.94, 26.91, 22.03]
    # [45.82, 33.89]
    # You can see that you have lists, not an int
    if transaction_dic_11[k] == 32.32:
        del transaction_dic_11[k]

Use in operator and .remove()

You need to detect if the value is IN the list, and remove it if necessary.

LBYL approach:

    if 32.32 in transaction_dic_11['breakfast blend']:
        transaction_dic_11['breakfast blend'].remove(32.32)

EAFP approach:

    try:
        transaction_dic_11['breakfast blend'].remove(32.32)
    except ValueError:
        pass

LBYL vs EAFP: Preventing or Handling Errors in Python

Upvotes: 1

Related Questions