Python -- Remove dictionary from multiple nested list of dictionary-CodePudding

I want to remove all of dict element in 'qas' list when its f1 is not 1.0.

Here is the list:

test_list = [
    {'paragraphs': [{
        'qas':[
            {'q':'abc','id':'123','a':['4','d'],'f1':1.0},
            {'q':'dsf','id':'343','a':['6','d'],'f1':0.5},
            {'q':'wre','id':'565','a':['4','u'],'f1':0.2}
        ]}
    ]},
    
    {'paragraphs': [{
        'qas':[
            {'q':'ujn','id':'874','a':['4','d'],'f1':1.0},
            {'q':'yht','id':'454','a':['5','d'],'f1':0.7},
            {'q':'nth','id':'676','a':['4','j'],'f1':0.4}
        ]}
    ]},
]

My expect result is:

test_list = [
    
    {'paragraphs': [{
        'qas':[
            {'q':'abc','id':'123','a':['4','d'],'f1':1.0}
        ]}
    ]},
    
    {'paragraphs': [{
        'qas':[
            {'q':'ujn','id':'874','a':['4','d'],'f1':1.0}
        ]}
    ]},
    
]

My current code:

for i in range(len(test_list)): 
    for j in range(len(test_list[i]['paragraphs'][0]['qas'])):
        if test_list[i]['paragraphs'][0]['qas'][j]['f1'] != 1:
            del test_list[i]['paragraphs'][0]['qas'][j]

However I got an index error:

      1 for i in range(len(test_list)):
      2     for j in range(len(test_list[i]['paragraphs'][0]['qas'])):
----> 3         if test_list[i]['paragraphs'][0]['qas'][j]['f1'] != 1:
      4             del test_list[i]['paragraphs'][0]['qas'][j]

IndexError: list index out of range

There are multiple layers of nested list and dict. Not sure how to solve this problem.

CodePudding user response：

IIUC, this can do the job.

for i in range(len(test_list)):
  test_list[i]["paragraphs"][0]["qas"] = test_list[i]["paragraphs"][0]["qas"][:1]

print(test_list)

Output -

[{'paragraphs': [{'qas': [{'a': ['4', 'd'],
      'f1': 1.0,
      'id': '123',
      'q': 'abc'}]}]},
 {'paragraphs': [{'qas': [{'a': ['4', 'd'],
      'f1': 1.0,
      'id': '874',
      'q': 'ujn'}]}]}]

CodePudding user response：

Tried this and it worked, but wanted to learn easier way to get this done.

import itertools

tmp = []
for i in range(len(test_list)): 
    for j in range(len(test_list[i]['paragraphs'][0]['qas'])):
        if test_list[i]['paragraphs'][0]['qas'][j]['f1'] != 1:
            tmp.append(False)
        else:
            tmp.append(True)        
    test_list[i]['paragraphs'][0]['qas'] = list(itertools.compress(test_list[i]['paragraphs'][0]['qas'],tmp))

CodePudding user response：

Code like this in Python will results in an index error，because del can change the length of the lst：

lst = [1,2,3,4]
for i in range(len(lst)):
    if lst[i] == 1:
        del lst[i]

If you want to filter the elements in the lst, you just need to do this:

lst = [i for i in lst if i==1]