45 — CSV: rows of data

A CSV file is plain text — one row per line, fields separated by commas; a small file only needs split(",").

#Steps

1. Create data.csv with one name,score row per line:

   Mina,90
   Yuna,70
   Sora,85
   Jun,75
   

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2. Read the file and cut it into rows: splitlines() splits the text into lines, and line.split(",") splits one row into fields:

   use file latest
   lines = file_read("data.csv").splitlines()
   parts = lines[0].split(",")
   show parts[0]
   show int(parts[1])
   

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3. Total the scores and divide by the row count for the average. Save it as scores.nme — it collects every row and writes a summary:

   # scores.nme — read a CSV, average the score column, write a summary.
   # Run: nme r scores
   
   use file latest
   
   raw = file_read("data.csv")
   lines = raw.splitlines()
   
   names = []
   scores = []
   for line in lines:
       parts = line.split(",")
       names.append(parts[0])
       scores.append(int(parts[1]))
   
   total = 0
   biggest = scores[0]
   for score in scores:
       total = total + score
       if score > biggest:
           biggest = score
   average = total / len(scores)
   
   show f"Read {len(lines)} rows from data.csv"
   for i in range(len(names)):
       show f"{names[i]}: {scores[i]}"
   show f"Total: {total}"
   show f"Average: {average}"
   show f"Highest: {biggest}"
   
   summary = f"rows,{len(lines)}\ntotal,{total}\naverage,{average}\nhighest,{biggest}\n"
   file_write("summary.csv", summary)
   show "Wrote summary.csv"
   

   copyrun it →

4. Run it next to data.csv, then look at the new summary.csv:

   nme r scores
   

   copy

   Read 4 rows from data.csv
   Mina: 90
   Yuna: 70
   Sora: 85
   Jun: 75
   Total: 320
   Average: 80.0
   Highest: 90
   Wrote summary.csv
   

   copy

   rows,4
   total,320
   average,80.0
   highest,90
   

   copy

#Try it yourself

Track the lowest score too — a lowest = scores[0] start, an if score < lowest check, and a lowest,<value> line in summary.

#What you learned

• file_read(...).splitlines() cuts a file into rows.
• line.split(",") splits a row into fields; parts[1] is the second field.
• int(parts[1]) turns text into a number before adding.
• file_write writes the summary back out as CSV.