在另一個用戶定義的函數中調用用戶定義的函數時發生Nameerror

Question

我需要編寫一個程序來打開和讀取文件，並包含單獨的用戶定義函數來計算文件中的行數和單詞數，例如linecount（），wordcount（）等。 我起草了以下代碼，但始終收到名稱錯誤，提示“未定義全局名稱'f'”。 f是應由openfile（）函數返回的文件句柄。 有什么建議嗎？

#open and read file
def openfile():
    import string
    name = raw_input ("enter file name: ")
    f = open (name)

# Calculates the number of paragraphs within the file 
def linecount():
    openfile()
    lines = 0
    for line in f:
        lines = lines + 1
    return lines

#call function that counts lines
linecount()

Answer 1

因為f是openfile中的局部變量

def openfile():
    import string
    name = raw_input ("enter file name: ")
    return open (name)

# Calculates the number of paragraphs within the file 
def linecount():
    f = openfile()
    lines = 0
    for line in f:
        lines = lines + 1
    return lines

甚至更短

def file_line_count():
    file_name = raw_input("enter file name: ")
    with open(file_name, 'r') as f:
        return sum(1 for line in f)