Perl中的log()函数返回传递给它的值的自然对数。如果调用时未传递值,则返回$_。 log()函数可用于使用以下公式查找任何底数的对数:
用法: log(value)
参数:
value:要计算的日志数
返回:
标量上下文中的浮点数
范例1:
#!/usr/bin/perl -w
# Calculating log of base 10
# using log function
print "log10(2): ", log10(2), "\n";
print "log10(7): ", log10(7), "\n";
print "log10(9): ", log10(9), "\n";
# Function for log10 calculator
sub log10
{
my $n = shift;
# using pre-defined log function
return log($n) / log(10);
}
输出:
log10(2): 0.301029995663981 log10(7): 0.845098040014257 log10(9): 0.954242509439325
范例2:
#!/usr/bin/perl -w
# Calculating log of different
# base using log function
print "log3(2): ", log3(2), "\n";
print "log5(7): ", log5(7), "\n";
print "log2(9): ", log2(9), "\n";
# Function for log3 calculator
sub log3
{
my $n = shift;
# using pre-defined log function
return log($n) / log(3);
}
# Function for log5 calculator
sub log5
{
my $n = shift;
# using pre-defined log function
return log($n) / log(5);
}
# Function for log2 calculator
sub log2
{
my $n = shift;
# using pre-defined log function
return log($n) / log(2);
}
输出:
log3(2): 0.630929753571457 log5(7): 1.20906195512217 log2(9): 3.16992500144231
相关用法
- Perl cos()用法及代码示例
- Perl ord()用法及代码示例
- Perl oct()用法及代码示例
- Perl abs()用法及代码示例
- Perl chr()用法及代码示例
- Perl int()用法及代码示例
- Perl sin()用法及代码示例
- Perl exp用法及代码示例
- Perl tell()用法及代码示例
- Perl each()用法及代码示例
- Perl uc()用法及代码示例
- Perl hex用法及代码示例
- Perl reverse()用法及代码示例
- Perl index()用法及代码示例
- Perl glob()用法及代码示例
注:本文由纯净天空筛选整理自Code_Mech大神的英文原创作品 Perl | log() Function。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。