Perl | eof–文件结束函数
函数的作用是检查是否达到了文件的结尾。如果达到了 EOF，或者文件句柄没有打开，并且在所有其他情况下都没有定义，则返回 1。
语法: eof(文件句柄)
参数: 文件句柄:用于打开文件
如果达到电渗流，则返回: 1
病例:
-
eof(FileHandle) : Passing FileHandle to eof() function. If File is empty then it returns 1 otherwise undef. Example:
```perl
!/usr/bin/perl
Opening Hello.txt file
open(fh,"<Hello.txt");
Checking if File is Empty or not
if(eof(fh)) # Returns 1 if file is empty # i.e. EOF encountered at the beginning { print("End Of File\n"); }
Closing the File
close(fh);
Checking if File is closed or not
using eof() function
if(eof(fh)) # fh is a closed file # and hence, eof returns 1 { print("File is closed"); } ```
输出:
- 如果 Hello.txt 为空:
- 如果 ex1.txt 不为空:
- eof() : The eof with empty parentheses refers to pseudo file formed from the files passed as command line arguments and is accessed via the ‘<>’ operator. eof() checks for the end of the last file of all the files passed as arguments in the command line.
Example:
```perl
!/usr/bin/perl
opens filehandle for files passed as arguments
while(<>) { # checks for eof of the last file passed as argument if(eof()) # It returns 1 if End Of the File is reached. { print "$_"; print("\nEnd Of File Reached"); }
else # prints each fileread of the File { print "$_"; } } ```
输出:
- 如果 Hello.txt 为空:
-
eof : eof with no parentheses checks for the End Of File of the last file read.
Example:
```perl
!/usr/bin/perl
opening Hello.plx
if(!open(fh, "<Hello.txt")) { print("File Not Found"); exit; }
if(eof fh) { print("Empty File"); exit; }
check for End Of File of last file read i.e. fh
if(not eof) # Returns 1 since eof is not reached { print("End Of File Not Reached"); }
Empty while loop to reach to the End Of File
while(
) { }; check for End Of File of last file read i.e. fh
if(eof) # Returns 1 since eof is reached { print("\nEnd Of File Reached"); } ```
输出:
