gnuplot 5中的时间/日期处理 [英] Time / date handling in gnuplot 5

问题描述

我有以下数据集

0   22/01   5:40.416    07/01   5:59.149
1   29/01   5:49.765    14/01   5:59.036
2   05/02   5:45.675    21/01   5:52.160
3   12/02   5:44.241    28/01   5:55.160
4   19/02   5:49.330    04/02   5:44.065
5   26/02   5:48.044    11/02   5:34.803

，我想将第3列绘制为2的函数(也将5绘制为4的函数，但这不是问题).格式为日/月和分钟:seconds.xxx.

and I want to plot column 3 as a function of 2 (and also 5 as a function of 4 but that is not the problem). The format are day/month and minutes:seconds.xxx.

在gnuplot 4.6中，通过为x和y设置不同的时间格式来指示如何读取这两列是很简单的.一个有效的最小脚本是:

In gnuplot 4.6 it was somewhat straightforward to indicate how to read both columns by setting distinct time formats for x and y. A minimal script that worked is:

set xdata time
set timefmt x "%d/%m"
set format x "%b"

set ydata time
set timefmt y "%M:%S"
set format y "%M:%S"

plot 'data.dat' using 2:3

我最近升级到gnuplot 5，命令set timefmt x "%d/%m"(及其等效的y)现在出现错误.看来您再也不能放置x或y了，并且整个脚本只能使用一个timefmt.

I recently upgraded to gnuplot 5 and the command set timefmt x "%d/%m" (and its y equivalent) now give an error. It seems that you cannot put x or y anymore, and you can only use a single timefmt for the whole script.

发行说明指出

使用时间格式生成轴刻度标签现在由 set {xy}tics time而不是set {xy}data time.因此，先验 不需要调用set xdata time或set timefmt x 输入或输出.这些较旧的命令仍然有效，但是 不推荐使用.

Use of time formats to generate axis tick labels is now controlled by set {xy}tics time rather than by set {xy}data time. Thus prior calls to set xdata time or set timefmt x are unnecessary for either input or output. These older commands still work, but are deprecated.

我有两个问题.首先，尽管显示旧命令仍然有效"，但在set timefmt x "%d/%m"上还是出现错误.其次，也是最重要的一点，我无法弄清楚如何教gnuplot如何使用新命令读取我的x和y列.

I have two issues. First, despite the indication that "older commands still work", I get an error on set timefmt x "%d/%m". Second, and most important, I couldn't figure out how to teach gnuplot how to read my x and y columns using the new commands.

注意:我从2011年开始看到此问题，但是我感觉不太优雅，我想将文件保留为当前格式.

Note: I have seen this question from 2011 but I don't find it elegant and I want to keep the files with the present format.

推荐答案

他们对这个新版本所做的改进实际上使其更加灵活.您可以为每个特定的时间列指定一种格式，而不是指定默认的时间格式然后要求您的列适合该格式.这样，您不必保持一致，只要您指定每列的格式即可.您还可以将时间格式用于 x 或 y 轴.

The improvement they made with this new version actually makes it more flexible. Rather than specify a default time format and then require your columns to fit that format, you can specify a format for each particular time column. This way you don't have to be consistent, as long as you specify each column's format. You can also use a time format for more than an x or y axis.

您引用的发行说明中提到了您问题的解决方案，但是并不能很好地解释它.使用timecolumn(N,"timeformat")函数，如下所示:

The solution to your question is mentioned in the release notes you quoted, but it doesn't explain it well. Use the timecolumn(N,"timeformat") function, like the following:

set xtics time
set format x "%b"

set ytics time
set format y "%M:%S"

plot 'data.dat' using (timecolumn(2, "%d/%m")):(timecolumn(3, "%M:%S"))

set timefmt行已被此新的两个参数timefunction()代替，它使您可以为using子句中的每一列指定格式.注意timecolumn()周围的().这意味着您可以(如果需要)使用时间值进行一些数学运算.根据相同的 5.0发行说明:

The set timefmt lines have been replaced by this new two-argument timefunction(), which allows you to specify the format for each column in the using clause. Notice the () around the timecolumn(). This means that you could (if you wanted) do some math with the time value. According to the same 5.0 release notes:

时间坐标在内部存储为相对于标准unix纪元1970年1月1日的秒数. gnuplot的早期版本内部使用了不同的纪元(2000年1月1日).此更改解决了外部生成以秒为单位的时间时引入的不一致问题.可以使用命令print strftime("%F",0)确定特定gnuplot安装所使用的纪元约定.现在，时间已存储到至少毫秒精度.

Time coordinates are stored internally as the number of seconds relative to the standard unix epoch 1-Jan-1970. Earlier versions of gnuplot used a different epoch internally (1-Jan-2000). This change resolves inconsistencies introduced when time in seconds was generated externally. The epoch convention used by a particular gnuplot installation can be determined using the command print strftime("%F",0). Time is now stored to at least millisecond precision.

注意对set xtics time的更改. xtics的输出格式与您的示例相同，并且不同于timecolumn()的第二个参数给出的输入格式.您似乎比以前具有更大的灵活性，但是语法已更改.

Notice the change to set xtics time. The output format for the xtics is the same as in your example, and is different from the input format given by the second argument to timecolumn(). You seem to have more flexibility than before, but the syntax has changed.

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