linux shell（leetcode）

194 Transpose File（leetcode）

https://leetcode.com/problems/transpose-file/

解析参考：http://www.cnblogs.com/grandyang/p/5382166.html

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file.txt (2行3列)

name agealice 21ryan 30

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awk '{    for (i = 1; i <= NF; ++i) {        printf("%d ",i);    }}' file.txt

打印出 1 2 1 2 1 2
说明 执行了3次for，每次for 循环两次（NF表示列数，有两列）

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$1 可以打印第一列的值，$2可以打印第2列的值

用一个数组 s[1]存第一列，s[2]存第二列

awk '{    for (i = 1; i <= NF; ++i) {        if(NR == 1)                s[i] = $i;        else                s[i] = s[i] " " $i;    }}END{        for(i = 1; i <= NF; ++i)                printf("%s\n", s[i]);}' file.txt

实现转置 打印出
name alice ryan
age 21 30

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192 Word Frequency

https://leetcode.com/problems/word-frequency/

words.txt

the day is sunny the thethe sunny is is

output(sorted by descending frequency)

the 4is 3sunny 2day 1

ac

cat words.txt| tr -s ' ' '\n' | sort -r | uniq -c | sort -rn | awk '{print $2 " " $1}'

参考：
在线疯狂
http://bookshadow.com/weblog/2015/03/24/leetcode-word-frequency/

主要命令

tr / sed
sort
uniq
awk

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