Powershell Count行非常大的文件 [英] Powershell Count lines extremely large file

问题描述

我有一个大小为 250 GB 的超大文本文件，是供应商提供给我们的.他们还为我们提供了一个控制文件，该文件应该包含大文件中的行数.有时会出现不匹配.如何计算 Powershell 中的行数?我试过这个命令，运行了半个多小时，还没完成.

I have a extremely large text file of size 250 GB that's given to us by a vendor. They also give us a control file that is supposed to have the number of lines in the large file. Sometimes there is a mismatch. How do I count lines in Powershell? I tried this command and it ran for more than half hour and was not done yet.

Get-content C:\test.txt | Measure-Object –Line

(gc C:\test.txt | Measure-object | select count).count

感谢任何帮助谢谢先生

推荐答案

如果性能很重要，请避免使用 cmdlet 和管道；使用 switch -File:

If performance matters, avoid the use of cmdlets and the pipeline; use switch -File:

$count = 0
switch -File C:\test.txt { default { ++$count } }

switch -File 枚举指定文件的行；条件 default 匹配任何行.

switch -File enumerates the lines of the specified file; condition default matches any line.

为了感受性能差异:

# Create a sample file with 100,000 lines.
1..1e5 > tmp.txt
# Warm up the file cache
foreach ($line in [IO.File]::ReadLines("$pwd/tmp.txt")) { }

(Measure-Command { (Get-Content tmp.txt | Measure-Object).Count }).TotalSeconds

(Measure-Command { $count = 0; switch -File tmp.txt { default { ++$count } } }).TotalSeconds

来自我的 Windows 10/PSv5.1 机器的示例结果:

Sample results from my Windows 10 / PSv5.1 machine:

1.3081307  # Get-Content + Measure-Object
0.1097513  # switch -File

也就是说，在我的机器上，switch -File 命令快了大约 12 倍.

That is, on my machine the switch -File command was about 12 times faster.

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