打印在python中出现搜索项的行

Question

我正在尝试让我的程序打印 Python 中出现搜索项的行。这是我目前的尝试：

search = input("Input your search term: ")  
found = 0
printline == False

with open ("search.txt", 'r') as data:
    for line in data: 
        if search.casefold() in line.casefold():
            found += line.casefold().count(search.casefold())  #adds the number of occurences within a line
            printline == True
        if printline == True:
            print(line)
        else: 
            printline == False

print("{} occurence(s) of the search item was/were found".format(found))

它一直说“打印线”未定义。我以为我在顶部定义了它。

更新：我将“printline”作为全局变量删除，并将其移至 for 循环的开头。现在代码打印每一行文本（不仅仅是包含搜索词的行）。这是我试图避免的，也是我想出“printline”变量开始的原因。

为了澄清，我试过了：

search = input("Input your search term: ")
found = 0


with open ("search.txt", 'r') as data:
    for line in data:
        if search.casefold() in line.casefold():
            found += line.casefold().count(search.casefold())  #adds the number of occurences within a line
            print(line)

print("{} occurence(s) of the search item was/were found".format(found)) 

我已经试过了：

search = input("Input your search term: ")
found = 0


with open ("search.txt", 'r') as data:
    for line in data:
        printline = False
        if search.casefold() in line.casefold():
            found += line.casefold().count(search.casefold())  #adds the number of occurences within a line
            printline = True
        if printline == True:
            print(line)
        else:
            printline = False

print("{} occurence(s) of the search item was/were found".format(found))

这两种方法最终都会吐出文本文件的每一行。有任何想法吗？感谢大家到目前为止的帮助。

Answer 1

您正在使用等价标记 (==) 来设置您的 printline 变量。

设置应该是“printline = False”，比较应该是“printline == False”

试试这个：

search = input("Input your search term: ")
found = 0
printline = False

with open ("search.txt", 'r') as data:
    for line in data:
        if search.casefold() in line.casefold():
            found += line.casefold().count(search.casefold())  #adds the number of occurences within a line
            printline = True
        if printline == True:
            print(line)
        else:
            printline = False

print("{} occurence(s) of the search item was/were found".format(found))

编辑：我们应该能够消除对 printline 变量的需求。

search = input("Input your search term: ")
found = 0

with open ("search.txt", 'r') as data:
    for line in data:
        if search.casefold() in line.casefold():
            found += line.casefold().count(search.casefold())  #adds the number of occurences within a line
            print(line) # This should only trigger if your if search.casefold() is in the line.casefold()

print("{} occurence(s) of the search item was/were found".format(found))