主页 / coding / 问题 / 78551072
Accepted
Gery
Asked: 2024-05-30 01:19:49 +0800 CST

比较两个文件后添加列

  • 772

我有一个包含 >19 000 行的文件，其结构如下：

$ head -10 a_vt
9999.77,-83.03,-7.71771771772,276.97,-7.71771771772
9999.48,-83.57,-7.23723723724,276.43,-7.23723723724
9999.08,-83.99,-7.2972972973,276.01,-7.2972972973
9998.75,-81.71,-6.996996997,278.29,-6.996996997
9998.75,-81.65,-6.996996997,278.35,-6.996996997
9998.69,-80.87,-8.7987987988,279.13,-8.7987987988
9998.34,-81.05,-8.43843843844,278.95,-8.43843843844
9997.89,-83.99,-6.21621621622,276.01,-6.21621621622
9997.77,-77.27,-16.1261261261,282.73,-16.1261261261
9997.54,-82.43,-4.29429429429,277.57,-4.29429429429
...
...

并使用这种类型的文件（即通常具有可变行数的文件）：

$ cat b_vm
22850,39.78686TN,39.78686TN,-75.6259,-14.9867,284.374,-14.9867
22901.9,9.90099TN,9.90099TN,-75.649,-14.9636,284.351,-14.9636
27742.2,160.0TN,160.0TN,-75.5999,-14.9922,284.4,-14.9922
22901.9,110.0TN,110.0TN,-75.6648,-14.9526,284.335,-14.9526
9998.69,110.0TN,110.0TN,-75.6551,-14.9496,284.345,-14.9496
9998.34,100.0TN,100.0TN,-75.62949999999998,-14.9573,284.37,-14.9573
27742.2,90.0TN,90.0TN,-75.60129999999998,-14.9973,284.399,-14.9973
27685.3,90.0TN,90.0TN,-75.6024,-14.9626,284.398,-14.9626
27742.2,80.0TN,80.0TN,-75.6014,-15.0006,284.399,-15.0006
22901.9,80.0TN,80.0TN,-75.6597,-14.9626,284.34,-14.9626

匹配第一列的值后，将 19k 行文件过滤掉，以获得：

$ awk 'NR==FNR { a[$1]; next }( ($1 in a) ) { print }' FS="," b_vm a_vt 
9998.69,-80.87,-8.7987987988,279.13,-8.7987987988
9998.34,-81.05,-8.43843843844,278.95,-8.43843843844

我不是awk这里的专家，但我知道这个单行 awk 调用允许在比较两个文件中第一列的值后从缓存中获取值。问题是打印第二列b_vmt以及如下：

9998.69,-80.87,-8.7987987988,279.13,-8.7987987988,**110.0TN**
9998.34,-81.05,-8.43843843844,278.95,-8.43843843844,**100.0TN**

任何提示都非常受欢迎，

bash

2 个回答

  1. Best Answer

    你可以使用这个awk：

    awk -F, 'NR==FNR { a[$1] = $2; next } $1 in a {print $0 "," a[$1]}' b_vm a_vt

9998.69,-80.87,-8.7987987988,279.13,-8.7987987988,110.0TN
9998.34,-81.05,-8.43843843844,278.95,-8.43843843844,100.0TN

    这里按索引a[$1] = $2存储$2在数组中。在第二遍中，我们打印文件中完整记录后的存储值。a$1a[$1]a_vt

    • 2

  2. 了解这一单行 awk 调用允许从缓存中获取值

    这不是真的。处理第一个文件时，对于您正在执行的每一行

    { a[$1]; next }

    第一部分仅引用元素，该元素可能尚不存在。来自（GNU Awk 用户指南

    对不存在元素的引用会自动创建该数组元素，并将空字符串作为其值。

    因此，执行此操作后，每个键的值a都是空字符串。

    • 1

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