使用sprintf打印字符串值 [英] Using sprintf to print string value

问题描述

实际上，我在Gnuplot中遇到了这个问题.但是以一种简单的方式，问题是我想使用sprintf以字符串格式打印，即使字符串由数字和符号组成.像这样:

Actually, I get this problem in Gnuplot. But in a simple way, the problem is I want to use sprintf to print in string format, even though the string consists of numbers and symbol. Like this:

a = '12/7'

sprintf('%.f', a)

我能够在Gnuplot中运行它，但是它只显示符号"/"之前的数字.我希望输出应打印变量a的所有内容，即'12/7'.对这种情况有什么建议吗?

I am able to run it in Gnuplot, but it only shows numbers before symbol "/". I expect the output should print all the content of variable a which is '12/7'. Any suggestion for this case?

推荐答案

如果要引用gnuplot中的sprintf内置函数，则文档help sprintf表示:

If you are referring to the sprintf built-in function in gnuplot, the documentation help sprintf says:

sprintf("format",var1,var2,...)应用标准C语言格式 指定多个参数，并返回结果字符串.如果 您要使用gnuplot自己的格式说明符，必须改为 呼叫gprintf().有关sprintf格式说明符的信息， 请参阅标准的C语言文档或Unix sprintf手册 页面.

sprintf("format",var1,var2,...) applies standard C-language format specifiers to multiple arguments and returns the resulting string. If you want to use gnuplot's own format specifiers, you must instead call gprintf(). For information on sprintf format specifiers, please see standard C-language documentation or the unix sprintf man page.

在%f的Unix手册页中说(被截断):

In the Unix man page for %f says (truncated):

％f，％F-将double参数四舍五入并转换为十进制 符号 格式为[-] ddd.ddd，其中 小数点字符等于精度规格.

%f, %F -- The double argument is rounded and converted to decimal notation in the style [-]ddd.ddd, where the number of digits after the decimal-point character is equal to the precision specification.

因此，您需要使用其他格式说明符.如fedorqui所指出，适当的格式说明符是%s.

Hence, you need to use a different format specifier. As fedorqui pointed out the appropriate format specifier is %s.

我经常参考此链接中的表以查找适当的格式说明符(我发现C手册页有点长).

I often refer to the table in this link for looking up the appropriate format specifiers (I find the C man page a bit long).

将sprintf与文件中的字符串一起使用

Using sprintf with strings from files

为了使用sprintf格式化文件中的字符串，您需要指定文件中的列以从中提取字符串信息.这需要使用stringcolumn命令来完成，而不仅仅是使用$符号.

In order to use sprintf to format a string from a file, you need to specify the column in the file to extract the string information from. This needs to be done using the stringcolumn command instead of just using a $ sign.

例如，如果要包含文件中的数字，则可以使用以下命令:

For example, if you wanted to include a number from a file you might use a command like:

plot "data.dat" using 1:2:(sprintf('%f', $3)) with labels

但是对于字符串，您需要:

But for a string you need:

plot "data.dat" using 1:2:(sprintf('%s', stringcolumn(3))) with labels

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