使用shell比较两个浮点数
【参考链接】http://stackoverflow.com/questions/35734666/floating-point-number-comparison-in-bash-script
【问题】
I tried to compare floating point number by -gt but it says that point expecting integer value. That means it can not handle floating point number . Then i tried the following code
我想用-gt比较两个浮点数大小，但屏幕却提示期望整数数值。
这就意味着-gt不能处理浮点数。接着我使用以下代码
chi_square=4
if [ "$chi_square>3.84" | bc ]
then
echo yes
else
echo no
fi
但屏幕却输出以下错误信息：
line 3: [: missing `]'
File ] is unavailable.
no
Here the no is echoed but it should be yes. I think that's because of the error it's showing. can anybody help me.
这里，执行结果本该是yes，此刻却提示no。我认为或许与提示的错误信息有关，谁能帮帮我呢？
【解决办法】
1.使用bc
要想使用bc的话请参考以下用法：
chi_square=4
if [[ $(bc -lexpr2
The result is 1 if expr1 is strictly greater than expr2.
2.使用awk
Just use awk instead
$ awk -v chi_square=4 'BEGIN{print (chi_square > 3.84 ? "yes" : "no")}'
yes
$ awk -v chi_square=3 'BEGIN{print (chi_square > 3.84 ? "yes" : "no")}'
no
或许，你并不喜欢使用三目运算，我也提供了使用shell变量来解决此问题。
$ chi_square=4
$ awk -v chi_square="$chi_square" 'BEGIN{
if (chi_square > 3.84) {
print "yes"
}
else {
print "no"
}
}'
yes
或
$ echo "$chi_square" |
awk '{
if ($0 > 3.84) {
print "yes"
}
else {
print "no"
}
}'
yes
或者
$ echo "$chi_square" | awk '{print ($0 > 3.84 ? "yes" : "no")}'
yes
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