Creating keys and its value inside a dictionary using for loop

Question

I want to create a dictionary in which each key will have names like doc1, doc2,....,doc2105 and it will store value from Title_Loans.documents[0],Title_Loans.documents[1],....,Title_Loans.documents[2104]. I am trying to run a for loop on length(Title_Loans.documents) inside a dictionary but it is showing error:

for i in range(len((Finance.documents)):
      ^
SyntaxError: invalid syntax

Below is the code I am running. Please suggest me how this can be done. Code: Sample:

docs = {
    'doc1': Title_Loans.documents[0],
    'doc2': Title_Loans.documents[1],
    'doc3': Title_Loans.documents[2],
    'doc4': Title_Loans.documents[3],
    'doc5': Title_Loans.documents[4]
}

Trying to run above code using for loop for large document size.

docs = {
for i in range(len((Finance.documents)):
    doc[i]: Finance.documents[i]
    }

You are mixing two syntaxes : normal for loop and dict comprehension (the latter being `docs = {i : Finance.documents[i] for i in range(len(Finance.documents))}` which you could more simply put : `docs = dict(enumerate(Finance.documents))` — Faibbus, May 24 '18 at 12:59

holdenweb · Accepted Answer · 2018-05-24T13:18:01.683

4

If you need a dictionary comprehension then you have to use comprehension syntax, not a statement (comprehensions are expressions):

docs = {"doc"+str(i): Finance.documents[i]
        for i in range(len(Finance.documents))}

This would, however, be much better written as

docs = {"doc"+str(i): documt for (i, documt) in enumerate(Finance.documents)}

I am unsure, though, why a dict that can be accessed with keys like "doc1", "doc2", etc. is better than a simple list, which can be accessed with integer keys.

edited May 24 '18 at 13:18

answered May 24 '18 at 12:58

holdenweb

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This is not working. Showing error: } ^ SyntaxError: invalid syntax – Ankita Patnaik May 24 '18 at 13:00
`doc[i]` is not what the user is expecting, her requirement is key name like `doc1`, `doc2` – akshat May 24 '18 at 13:11
To start with 'doc1' you would need `str(i+1)` – ap91484 May 24 '18 at 13:21
1

Actually I want to create a document-term matrix using different lists as separate documents and that's why I converted it to a dict. – Ankita Patnaik May 24 '18 at 13:22
Does this mean the terms are held in a separate list? – ap91484 May 24 '18 at 13:25

score 0 · Answer 2 · answered May 24 '18 at 12:59

0

Try:

for i in range(len(Finance.documents)):

for your invalid syntax error.

answered May 24 '18 at 12:59

Xantium

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score 0 · Answer 3 · answered May 24 '18 at 13:03

0

If you want your keys to take the form "doc(num)" then create a string doc_format = "doc{}"

then run:

docs = {doc_format.format(index+1): Finance.documents[index] for index in range(len(Finance.documents))}

answered May 24 '18 at 13:03

letroot

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Or enumerate over the list: `docs = { doc_format.format(index+1): f for index, f in enumerate(Finance.documents)}` – ap91484 May 24 '18 at 13:10

score 0 · Answer 4 · answered May 24 '18 at 13:03

You are not using the correct dict-comprehension syntax, it should be:

{key, value for key in your_iterable}

where, value can be some function of key or vice-versa

For your case:

docs = {"doc{}".format(i + 1): Finance.documents[i] for i in range(len(Finance.documents))}

score 0 · Answer 5 · answered May 24 '18 at 13:05

0

You could try this as well,

doc = {}
for i in range(len(Finance.documents)):
   doc[i] = Finance.documents[i]
print(doc)

answered May 24 '18 at 13:05

Narendra Prasath

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OP is getting syntax errot in `dict-comprehension`, your answer does not address that. – akshat May 24 '18 at 13:14
Are you iterating list right? or elaborate where error occurs? – Narendra Prasath May 24 '18 at 13:16

Creating keys and its value inside a dictionary using for loop

5 Answers5