Perl Language Learning 0512

#!/usr/bin/perl-w
@lines = ' Perdoc-u-fatan2 '; Don't confuse anti-quotes with single quotes
foreach (@lines)
{
s/\w< (^>}+) >/\U$1/g;
Print
#print "Hello, world!\n"
}


Scalar is the simplest data type in Perl.
For most scalars, it is either a number or a sequence of characters.

You can manipulate the scalar with an operator, and the resulting result is usually a scalar. Scalars can be stored in scalar variables,
These locations can also be read from and written to files and devices.

Inside Perl, the numbers are always saved and calculated by the requirement of double-precision floating-point numbers.
That is, there is no integer value inside perl---The integer constants used in the program are converted to the equivalent floating-point values.

Floating Point Direct quantity
Refers to the wording of a number in the Perl source code. The direct amount is not the result of the operation, nor is it the result of the action, it is
Type the data in the program source code directly.

2**3 represents 2 of the 3-time side, with a result of 8

A string is usually made up of alphanumeric letters, numbers, and punctuation marks, which range from 32 to 126 of ASCII encoding.


"Fred" x 3 #得到 "fredfredfred"
"Barney" x (4+1) #得 "Barneybarneybarneybarneybarney"
5 x 4.8 #本质上就是 "5" x 4, so "5555"
The number of repetitions (right operand) is rounded before use (4.8 becomes 4). The number of repetitions is less than 1 o'clock, resulting in a zero length
An empty string.

Operators that operate on numbers (such as multiplication) if you encounter operands of type string, Perl automatically converts the string to
The equivalent decimal floating-point number to perform the operation. The result of "12" * "3" is 36
The non-numeric part of the string is skipped, and "12fred34" * "3" will get 36.

P52