CODEWITHSUNDEEP
pythonpython-3.x
Srikanth Gopalakrishnan
Srikanth Gopalakrishnan

Reputation: 844

Remove Objects Containing certain Data from a list

We are all well aware that we can insert a vast array of datatypes into a python list. For eg. a list of characters 

X=['a','b','c']

To remove 'c' all i have to do is

X.remove('c')

Now What I need is to remove an object containing a certain string.

class strng:
    ch = ''
    i = 0
X = [('a',0),('b',0),('c',0)]              #<---- Assume The class is stored like this although it will be actually stored as object references
Object = strng()
Object.ch = 'c'
Object.i = 1
X.remove('c')                    #<-------- Basically I want to remove the Object containing ch = 'c' only. 
                                 #           variable i does not play any role in the removal
print (X)

Ans I want:

[('a',0),('b',0)]                   #<---- Again Assume that it can output like this

Upvotes: 0

Views: 84

Answers (3)

napuzba
napuzba

Reputation: 6288

The following function will remove in place all the items for them condition is True:

def remove(list,condtion):
    ii = 0
    while ii < len(list):
        if condtion(list[ii]):
            list.pop(ii)
            continue        
        ii += 1

Here how you can use it:

class Thing:
    def __init__(self,ch,ii):
        self.ch = ch
        self.ii = ii
    def __repr__(self):
        return '({0},{1})'.format(self.ch,self.ii)

things = [ Thing('a',0), Thing('b',0) , Thing('a',1), Thing('b',1)]     
print('Before ==> {0}'.format(things))         # Before ==> [(a,0), (b,0), (a,1), (b,1)]
remove( things , lambda item : item.ch == 'b')
print('After  ==> {0}'.format(things))         # After  ==> [(a,0), (a,1)]

Upvotes: 1

Burhan Khalid
Burhan Khalid

Reputation: 174624

I think what you want is this:

>>> class MyObject:
...    def __init__(self, i, j):
...      self.i = i
...      self.j = j
...    def __repr__(self):
...       return '{} - {}'.format(self.i, self.j)
...
>>> x = [MyObject(1, 'c'), MyObject(2, 'd'), MyObject(3, 'e')]
>>> remove = 'c'
>>> [z for z in x if getattr(z, 'j') != remove]
[2 - d, 3 - e]

Upvotes: 1

Jossie Calderon
Jossie Calderon

Reputation: 1425

For the list

X = [('a',0),('b',0),('c',0)]

If you know that the first item of a tuple is always a string, and you want to remove that string if it has a distinct value, then use a list comprehension:

X = [('a',0),('b',0),('c',0)] 

X = [(i,j) for i, j in X if i != 'c']

print (X)

Outputs the following:

[('a', 0), ('b', 0)]

Upvotes: 0

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