我有这段代码，我得到(standard_in) 1: syntax error来自第三行的(standard_in) 1: syntax error ：
valueInFloat=printf "%.2g" $temp tempFloat=printf "%.1f" $value2 compare_result=`echo "$tempFloat < $valueInFloat" |bc -l` if [[ -z $compare_result ]] then ...我试图在bash进行浮点值比较。
请注意，如果我注释掉第三行并将compare_result=0 ，则错误消失。
I have this piece of code where I am getting (standard_in) 1: syntax error from the third line:
valueInFloat=printf "%.2g" $temp tempFloat=printf "%.1f" $value2 compare_result=`echo "$tempFloat < $valueInFloat" |bc -l` if [[ -z $compare_result ]] then ...I am trying to do float value comparison in bash.
Note that, if I comment out the third line and put compare_result=0, the error goes away.
最满意答案
在某些情况下， printf可以生成bc无法识别的浮点值。 具体来说，类似于：
pax> printf "%.2g\n" 42456456457357357 4.2e+16 pax> echo '4.2e+16 > 1.0' | bc -l (standard_in) 1: syntax error我建议你坚持使用%f变种。 它将始终根据ISO C标准生成[−]999.999格式， bc将毫无困难（除非您开始进入无穷大或NaN）。 %g变体生成该格式或%e格式[−]9.999e±99具体取决于请求的值和精度。
另外，你的测试是错误的。 如果字符串为空，则-z测试将为true，并且您的字符串将为1或0具体取决于比较结果。 一个更好的测试是（假设你想在测试结果为肯定时休息：
if [[ ${compare_result} -eq 1 ]]There are situations in which printf can generate floating point values that bc won't recognise. Specifically, something like:
pax> printf "%.2g\n" 42456456457357357 4.2e+16 pax> echo '4.2e+16 > 1.0' | bc -l (standard_in) 1: syntax errorI suggest you stick with the %f variant. It will always generate the form [−]999.999 as per the ISO C standard, which bc will have no trouble with (unless you start getting into infinities or NaNs). The %g variant generates either that format or the %e format [−]9.999e±99 depending on the value and precision requested.
In addition, your test is wrong. The -z test will be true if the string is empty, and your string will either be 1 or 0 depending on the result of the comparison. A better test would be (assuming you wanted to rest if the test was positive:
if [[ ${compare_result} -eq 1 ]]bash float比较和（standard_in）1：语法错误(bash float comparison and (standard_in) 1: syntax error)我有这段代码，我得到(standard_in) 1: syntax error来自第三行的(standard_in) 1: syntax error ：
valueInFloat=printf "%.2g" $temp tempFloat=printf "%.1f" $value2 compare_result=`echo "$tempFloat < $valueInFloat" |bc -l` if [[ -z $compare_result ]] then ...我试图在bash进行浮点值比较。
请注意，如果我注释掉第三行并将compare_result=0 ，则错误消失。
I have this piece of code where I am getting (standard_in) 1: syntax error from the third line:
valueInFloat=printf "%.2g" $temp tempFloat=printf "%.1f" $value2 compare_result=`echo "$tempFloat < $valueInFloat" |bc -l` if [[ -z $compare_result ]] then ...I am trying to do float value comparison in bash.
Note that, if I comment out the third line and put compare_result=0, the error goes away.
最满意答案
在某些情况下， printf可以生成bc无法识别的浮点值。 具体来说，类似于：
pax> printf "%.2g\n" 42456456457357357 4.2e+16 pax> echo '4.2e+16 > 1.0' | bc -l (standard_in) 1: syntax error我建议你坚持使用%f变种。 它将始终根据ISO C标准生成[−]999.999格式， bc将毫无困难（除非您开始进入无穷大或NaN）。 %g变体生成该格式或%e格式[−]9.999e±99具体取决于请求的值和精度。
另外，你的测试是错误的。 如果字符串为空，则-z测试将为true，并且您的字符串将为1或0具体取决于比较结果。 一个更好的测试是（假设你想在测试结果为肯定时休息：
if [[ ${compare_result} -eq 1 ]]There are situations in which printf can generate floating point values that bc won't recognise. Specifically, something like:
pax> printf "%.2g\n" 42456456457357357 4.2e+16 pax> echo '4.2e+16 > 1.0' | bc -l (standard_in) 1: syntax errorI suggest you stick with the %f variant. It will always generate the form [−]999.999 as per the ISO C standard, which bc will have no trouble with (unless you start getting into infinities or NaNs). The %g variant generates either that format or the %e format [−]9.999e±99 depending on the value and precision requested.
In addition, your test is wrong. The -z test will be true if the string is empty, and your string will either be 1 or 0 depending on the result of the comparison. A better test would be (assuming you wanted to rest if the test was positive:
if [[ ${compare_result} -eq 1 ]]
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