Perl | tell()函数

原文:https://www.geeksforgeeks.org/perl-tell-function/

Perl 中的 tell()函数用于通过使用文件句柄获取文件中读取指针的位置。如果没有传递文件句柄，则返回最近访问的文件中的位置。

语法:告诉(文件句柄)

参数: 要访问文件的文件句柄:文件句柄。

返回:读指针的当前位置

例 1:

#!/usr/bin/perl 

# Opening a File in Read-only mode 
open(fh, "<", "Hello.txt"); 

$position = tell(fh);
print("Position of read pointer before reading: $position");

# Reading first 10 characters from the file
for($i = 0; $i < 10; $i++)
{
    $ch = getc(fh);
}

$position = tell(fh);

# Current position of the read pointer
print("\nCurrent Position: $position");

# Closing the File 
close(fh); 

输出:

例 2:

#!/usr/bin/perl 

# Opening a File in Read-only mode 
open(fh, "<", "Hello.txt"); 

$position = tell(fh);
print("Position of read pointer before reading: $position\n");

# Printing First 10 Characters
print("First ten characters are: ");

# Reading and printing first 
# 10 characters from the file
for($i = 0; $i < 10; $i++)
{
    $ch = getc(fh);
    print" $ch";
}

$position = tell(fh);

# Current position of the read pointer
print("\nCurrent Position: $position");

# Closing the File 
close(fh); 

输出:

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