Pipes实现LeetCode(195.第十行)

[LeetCode] 195.Tenth Line 第十行

How would you print just the 10th line of a file?

For example, assume that file.txt has the following content:

Line 1
Line 2
Line 3
Line 4
Line 5
Line 6
Line 7
Line 8
Line 9
Line 10

Your script should output the tenth line, which is:

Line 10

[show hint]

Hint:
1. If the file contains less than 10 lines, what should you output?
2. There's at least three different solutions. Try to explore all possibilities.

这道题让我们用Bash脚本来打印一个txt文件的第十行，可以用很多种方法来实现，我们先来看一种是用awk来实现的方法，awk是强大的文本分析工具，具有流控制、数学运算、进程控制、内置的变量和函数、循环和判断的功能。其中NR表示行数，$0表示当前记录，所以我们可以用if来判断行数为第十行时，将内容打印出来即可：

解法一：

awk '{if(NR == 10) print $0}' file.txt

我们也可以用更简洁的写法来打印出第十行如下：

解法二：

awk 'NR == 10' file.txt

我们也可以使用流编辑工具sed来做。-n默认表示打印所有行，p限定了具体打印的行数：

解法三：

sed -n 10p file.txt

我们也可以使用tail和head关键字来打印。其中head表示从头开始打印，tail表示从结尾开始打印，-你表示根据文件行数进行打印，一些区别与联系请见下列例子：

tail -n 3 file.txt: 打印file文件的最后三行内容　　　　　　

tail -n +3 file.txt： 从file文件第三行开始打印所有内容

head -n 3 file.txt： 打印file文件的前三行

head -n -3 file.txt： 打印file文件除了最后三行的所有内容

至于竖杠|为管道命令，用法: command 1 | command 2 他的功能是把第一个命令command1执行的结果作为command 2的输入传给command 2。了解了这些知识，那么下面一行命令就很好理解了，首先输入file文件从第十行开始的所有内容，然后将输出内容的第一行打印出来即为第十行：

解法四：

tail -n +10 file.txt | head -n 1

下面这种方法跟上面刚好相反，先输出file文件的前十行，然后从输出的第十行开始打印，那么也能正好打印第十行的内容：

解法五：

head -n 10 file.txt | tail -n +10

参考资料：

https://leetcode.com/discuss/29526/super-simple-solution

https://leetcode.com/discuss/29591/simple-solution-using-awk

到此这篇关于Pipes实现LeetCode(195.第十行)的文章就介绍到这了,更多相关Pipes实现第十行内容请搜索我们以前的文章或继续浏览下面的相关文章希望大家以后多多支持我们！

赞 (0)

相关推荐

  • SQL实现LeetCode(185.系里前三高薪水)

    [LeetCode] 185.Department Top Three Salaries 系里前三高薪水 The Employee table holds all employees. Every employee has an Id, and there is also a column for the department Id. +----+-------+--------+--------------+ | Id | Name  | Salary | DepartmentId | +--

  • C++实现LeetCode(188.买卖股票的最佳时间之四)

    [LeetCode] 188.Best Time to Buy and Sell Stock IV 买卖股票的最佳时间之四 Say you have an array for which the ith element is the price of a given stock on day i. Design an algorithm to find the maximum profit. You may complete at most k transactions. Note: You m

  • C++实现LeetCode(191.位1的个数)

    [LeetCode] 191.Number of 1 Bits 位1的个数 Write a function that takes an unsigned integer and returns the number of '1' bits it has (also known as the Hamming weight). For example, the 32-bit integer '11' has binary representation 00000000000000000000000

  • C++实现LeetCode(186.翻转字符串中的单词之二)

    [LeetCode] 186. Reverse Words in a String II 翻转字符串中的单词之二 Given an input string , reverse the string word by word.  Example: Input:  ["t","h","e"," ","s","k","y"," ","i&qu

  • C++实现LeetCode(557.翻转字符串中的单词之三)

    [LeetCode] 557.Reverse Words in a String III 翻转字符串中的单词之三 Given a string, you need to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order. Example 1: Input: "Let's take LeetCode conte

  • Pipes实现LeetCode(192.单词频率)

    [LeetCode] 192.Word Frequency 单词频率 Write a bash script to calculate the frequency of each word in a text file words.txt. For simplicity sake, you may assume: words.txt contains only lowercase characters and space ' ' characters. Each word must consis

  • C++实现LeetCode(309.买股票的最佳时间含冷冻期)

    [LeetCode] 309.Best Time to Buy and Sell Stock with Cooldown 买股票的最佳时间含冷冻期 Say you have an array for which the ith element is the price of a given stock on day i. Design an algorithm to find the maximum profit. You may complete as many transactions as

  • C++实现LeetCode(190.颠倒二进制位)

    [LeetCode] 190. Reverse Bits 颠倒二进制位 Reverse bits of a given 32 bits unsigned integer. Example 1: Input: 00000010100101000001111010011100 Output: 00111001011110000010100101000000 Explanation: The input binary string 00000010100101000001111010011100 re

  • Pipes实现LeetCode(195.第十行)

    [LeetCode] 195.Tenth Line 第十行 How would you print just the 10th line of a file? For example, assume that file.txt has the following content: Line 1 Line 2 Line 3 Line 4 Line 5 Line 6 Line 7 Line 8 Line 9 Line 10 Your script should output the tenth li

  • Pipes实现LeetCode(194.转置文件)

    [LeetCode] 194.Transpose File 转置文件 Given a text file file.txt, transpose its content. You may assume that each row has the same number of columns and each field is separated by the ' ' character. For example, if file.txt has the following content: na

  • Pipes实现LeetCode(193.验证电话号码)

    [LeetCode] 193.Valid Phone Numbers 验证电话号码 Given a text file file.txt that contains list of phone numbers (one per line), write a one liner bash script to print all valid phone numbers. You may assume that a valid phone number must appear in one of th

  • C++实现LeetCode(119.杨辉三角之二)

    C++实现LeetCode(119.杨辉三角之二)

    [LeetCode] 119. Pascal's Triangle II 杨辉三角之二 Given a non-negative index k where k ≤ 33, return the kth index row of the Pascal's triangle. Note that the row index starts from 0. In Pascal's triangle, each number is the sum of the two numbers directly

  • LeetCode -- Path Sum III分析及实现方法

    LeetCode -- Path Sum III分析及实现方法 题目描述: You are given a binary tree in which each node contains an integer value. Find the number of paths that sum to a given value. The path does not need to start or end at the root or a leaf, but it must go downwards

  • 基于Java实现杨辉三角 LeetCode Pascal's Triangle

    基于Java实现杨辉三角 LeetCode Pascal's Triangle

    Pascal's Triangle Given numRows, generate the first numRows of Pascal's triangle. For example, given numRows = 5, Return [ [1], [1,1], [1,2,1], [1,3,3,1], [1,4,6,4,1] ] 这道题比较简单, 杨辉三角, 可以用这一列的元素等于它头顶两元素的和来求. 数学扎实的人会看出, 其实每一列都是数学里的排列组合, 第4行, 可以用 C30 =

  • vscode中配置LeetCode插件的教程(愉快刷题)

    大家好,今早在B站看到up主的vscode里藏了leetcode插件,这才知道原来还有这款神器.但是没想到在用的时候遇到了一些麻烦,花了一点时间才解决.所以写这篇文章除了给大家安利这个好用的插件之外,也是为了帮助更多的同学避免踩坑. 简介vscode vscode在工业界鼎鼎大名,被誉为微软少有的拿得出手的精品(逃).原本是不想过多赘述的,但是鉴于许多粉丝还是正在上学的萌新,所以花点笔墨简单介绍一下. vscode是微软开发的编辑器,严格说起来它并不是一个IDE,只是一个编辑器.但是由于它支持嵌

  • vscode+leetcode环境配置方法

    前言 之前安装anaconda3的时候,选择了同时安装vscode,但从来没有正式去接触过它.最近,偶然想到看看leetcode,发现在vscode上搞leetcode很方便,于是就开始倒腾起来了. vscode配置 如何安装我就不详述了,win/ubuntu下的安装可参见我的博客: vscode+python+c++ 我现在的vscode的版本是:1.43.1 需要安装的插件有: anaconda extension pack: 支持非python官方的三方库code runner:F5快捷运

  • vscode配置leetcode插件并解决无法登录问题(图文详解)

    官方文档 https://github.com/LeetCode-OpenSource/vscode-leetcode/blob/master/docs/README_zh-CN.md 1.环境 window10 vscode 1.23.0+ Node.js 10+ 如果Node.js 没添加到环境变量需要手动添加,添加成功在cmd中输入node --version会显示:  2.配置 vscode安装leetcode插件: 安装完右侧会出现: 此时发现账号密码方式无法登录(本次教程都针对国际版

随机推荐