[JAVA] 10. Counting the number of lines

10. Counting the number of lines

Count the number of lines. Use the wc command for confirmation.

Go

package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	//Specify the read file
	name := "../hightemp.txt"
	line := 0

	//Open the file to read
	f, err := os.Open(name)
	if err != nil {
		fmt.Printf("os.Open: %#v\n",err)
		return
	}
	defer f.Close() //Crease at the end

	//Create a scanner library
	scanner := bufio.NewScanner(f)

	//Read one line of data
	for scanner.Scan() {
		line++;
	}

	//Check if there was an error
	if err = scanner.Err(); err != nil {
		fmt.Printf("scanner.Err: %#v\n",err)
		return
	}

	//Show number of lines
	fmt.Println("Line",line)
}

python

import sys

line = 0

#Open file
with open("../hightemp.txt", "r") as f:
    #Read line by line
    for data in f:
        #Add the number of lines
        line += 1

#Show number of lines
print("Line",line)

Javascript

//Module loading
var fs = require("fs");
var readline = require("readline");

var line = 0;

//Create a stream
var stream = fs.createReadStream("../hightemp.txt", "utf8");

//Pass Stream to readline
var reader = readline.createInterface({ input: stream });

//Row read callback
reader.on("line", (data) => {
    line = line + 1
});

//Close callback
reader.on("close", function () {
    console.log("Line",line);
});

Summary

Finally, we entered "Chapter 2: UNIX Command Basics"! !! ..

I heard that I entered Chapter 2, so I finally changed the Python version setting to 3.7. It's just an IDE setting ... Find out where the settings are ... Excuse me.

While checking each language to read the file. Go, Python didn't bother me so much, Javascirpt. Oh oh. Something interesting. Is it necessary to be careful about the way of thinking because it is asynchronous?

Supplement

The variable name was fname in Go language, but IDE (Golang) says typo ?. I wonder if I'm grateful. For the time being, change it to name and avoid it.

Top

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