Python3 file.readline()方法

readline()方法從檔案中讀取一個完整的行。結尾的換行符也保持在字串中。如果引數 size 存在且非負，這是一個最大位元組數，包括結尾的換行和不完整的行可能被返回。

當遇到EOF，一個空字串立即被返回。

語法

下面是 readline()方法的語法-

fileObject.readline( size );

引數

size -- 這是從檔案中讀取的位元組數。

返回值

此方法從檔案中返回讀取的行。

範例

下面的例子顯示 readline() 方法的使用。

Assuming that 'foo.txt' file contains following text:
This is 1st line
This is 2nd line
This is 3rd line
This is 4th line
This is 5th line

#!/usr/bin/python3

# Open a file
fo = open("foo.txt", "r+")
print ("Name of the file: ", fo.name)

line = fo.readline()
print ("Read Line: %s" % (line))

line = fo.readline(5)
print ("Read Line: %s" % (line))

# Close opened file
fo.close()

當我們執行上面的程式，會產生以下結果 -

Name of the file:  foo.txt
Read Line: This is 1st line

Read Line: This