You have a CSV file with columns 'id', 'name', and 'score'. You want to read it using csv.DictReader and create a dictionary mapping each 'id' to the 'score' as an integer. Which code snippet correctly does this?
Awith open('data.csv') as f:
reader = csv.DictReader(f)
result = {int(row['id']): row['score'] for row in reader}
Bwith open('data.csv') as f:
reader = csv.DictReader(f)
result = {row['id']: int(row['score']) for row in reader}
Cwith open('data.csv') as f:
reader = csv.reader(f)
result = {row['id']: int(row['score']) for row in reader}
Dwith open('data.csv') as f:
reader = csv.DictReader(f)
result = {row['score']: int(row['id']) for row in reader}
Step-by-Step Solution
Solution:
Step 1: Use DictReader to access columns by name
Only csv.DictReader allows accessing 'id' and 'score' by keys.
Step 2: Create dictionary with 'id' as key and integer 'score' as value
with open('data.csv') as f:
reader = csv.DictReader(f)
result = {row['id']: int(row['score']) for row in reader} correctly converts 'score' to int and uses 'id' as key.
Final Answer:
with open('data.csv') as f:
reader = csv.DictReader(f)
result = {row['id']: int(row['score']) for row in reader} -> Option B
Quick Check:
DictReader + dict comprehension + int conversion [OK]
Quick Trick:Use DictReader and dict comprehension with int() conversion [OK]
Common Mistakes:
Using csv.reader instead of DictReader
Swapping keys and values in dictionary
Not converting score to int
Converting id to int instead of score
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