You want to read a file and count how many lines contain the word 'error'. Which code correctly uses File.open with a block to do this?

hard📝 Application Q8 of 15

Ruby - File IO

You want to read a file and count how many lines contain the word 'error'. Which code correctly uses File.open with a block to do this?

Acount = 0 File.open('log.txt', 'r') do |f| f.each_line { |line| count += 1 if line.include?('error') } end puts count

Bcount = 0 f = File.open('log.txt', 'r') f.each_line { |line| count += 1 if line.include?('error') } f.close puts count

Ccount = 0 File.open('log.txt', 'w') do |f| f.each_line { |line| count += 1 if line.include?('error') } end puts count

Dcount = 0 File.open('log.txt') { |f| f.read.each { |c| count += 1 if c == 'error' } } puts count

Step-by-Step Solution

Solution:

Step 1: Use File.open with block and read mode
count = 0 File.open('log.txt', 'r') do |f| f.each_line { |line| count += 1 if line.include?('error') } end puts count opens the file in read mode 'r' with a block, which auto-closes the file.
Step 2: Count lines containing 'error'
Inside the block, it iterates each line and increments count if 'error' is found.
Final Answer:
count = 0 File.open('log.txt', 'r') do |f| f.each_line { |line| count += 1 if line.include?('error') } end puts count -> Option A
Quick Check:
File.open with block + read mode + line iteration = A [OK]

Quick Trick: Use File.open with block and 'r' mode to read safely [OK]

Common Mistakes:

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