使用列值以CSV格式执行每列数学

Question

我尝试使用PowerShell拾取CSV文件，从另一列中减去一列的值并将其放入第三列，然后将CSV打印到默认打印机。

除了数学之外我一切正常。它导入，设置我的标题和打印。但是，似乎没有执行我的merge来进行数学运算。它运行没有错误。

foreach

有人能告诉我为什么数学部分（$hhsignscsv = Import-Csv -Header ("PLU","Description","Quantity","Price","FreqShopType","FreqShopValue","FreqShopPrice","LabelFormat","LabelQTY","SizeMeasurement","Limit") -Path hhsignsmod.csv foreach ($hhsigns in $hhsignscsv) { $PLU = $hhsigns.PLU $Description = $hhsigns.Description $Quantity = $hhsigns.Quantity $Price = $hhsigns.Price $FreqShopType = $hhsigns.FreqShopType $FreqShopValue = $hhsigns.FreqShopValue $FreqShopPrice = $hhsigns.FreqShopPrice $LabelFormat = $hhsigns.LabelFormat $LabelQTY = $hhsigns.LabelQTY $SizeMeasurement = $hhsigns.SizeMeasurement $Limit = $hhsigns.Limit } foreach ($hhsigns in $hhsignscsv) { $FreqShopPrice = $Price - $FreqShopValue } Out-Printer -InputObject $hhsignscsv ）不会将这些值放入$FreqShopPrice = $Price - $FreqShopValue列吗？在调试或运行时，我没有遇到任何语法错误，但在打印输出时，$FreqShopPrice为空，而不是包含减法的值。

Answer 1

声明

$FreqShopPrice = $hhsigns.FreqShopPrice

将CSV字段FreqShopPrice的值复制到变量$FreqShopPrice。

声明

$FreqShopPrice = $Price - $FreqShopValue

使用变量$FreqShopPrice和$Price之间的差异更新变量$FreqShopValue。但是，由于您在当前循环之前在单独的循环中填充了这些变量，因此它们包含来自CSV的最后一条记录的值。

要实际更新CSV中的字段FreqShopPrice，您需要这样做：

foreach($hhsigns in $hhsignscsv) {
  $hhsigns.FreqShopPrice = $hhsigns.Price - $hhsigns.FreqShopValue
}

删除另一个循环。除了刻录CPU周期外，它没有用处。