Question

好的我有这个文本文件结构

Customer ID: 1
Customer Name: John
Customer Sale: 5

假设我希望使用客户ID搜索此条目的文本文件并返回客户销售的内容：这是5

我有类似的东西

with open("sales.txt", "r") as salesFile:
        lines = salesFile.readlines()
        for line in lines:
            if (str(ID)) in line:
                return ????

不确定如何从我搜索

的两行中返回一个值

提前致谢

Answer 1

不需要分割线，那么file将是一个迭代器：你可以这样做：

def match_line(ID, f):
    with open(f) as file:
        for line in file:
            if str(ID) in line:
                for line2 in file:
                    if 'Sale' in line2:
                        return line2

用文件调用时

：

In [9]: match_line(1, 'sales.txt')
Out[9]: 'Customer Sale: 5\n'

这假设您想要带有字符串＆＃39; Sale＆＃39;在它上面，如果你想要之后的2行：

def match_line(ID, f):
    with open(f) as file:
        for line in file:
            if str(ID) in line:
               next(file)
               return next(file)

Answer 2

你想要接下来的两行，这就是匹配后的下两行

with open("a.txt") as sales:
    lines=sales.readlines()

    for i in range(len(lines)-1):
        if ("ID: "+str(5)) in lines[i]:
            print lines[i+1],lines[i+2]

<强> 输出：

Customer Name: John
Customer Sale: 5

使用枚举器：

with open("a.txt") as sales:
    lines=sales.readlines() 
         for i,a in enumerate(lines):
             if ("ID: "+str(5)) in a:
                 print lines[i+2]

<强>输出：

Customer Sale: 5

Answer 3

在这里你可以找到两个解决方案，第二个是pythonic。这两个函数都将Customer ID作为参数，第二个是客户ID行与要返回的所需行之间的偏移量，最后一个是输入文件。如果id不存在，则函数返回None。如果您不需要将偏移量传递给函数，则可以删除它并在函数内部声明

def get_id_details(c_id,offset,in_file):
    base_line = 'Customer ID: %s' % c_id
    find = False
    with open(in_file) as f:
        for line in f:
            if (base_line == line.rstrip('\r\n') and not find ):
                find = True
            if (find):
                offset -=1
            if offset ==-1:
                return line
    return None  

def get_id_details_2(c_id,offset,in_file):
    base_line = 'Customer ID: %s' % c_id
    with open(in_file) as f:
        for line in f:
            if (base_line == line.rstrip('\r\n')):
                try:
                    for _ in range(offset-1):
                        f.next()
                    return f.next()
                except StopIteration:
                    return None
print get_id_details(2,2,'in.txt')
// result is Customer Sale: 5
print get_id_details(8,6,'in.txt')
// result is None

print get_id_details_2(2,2,'in.txt')
// result is Customer Sale: 6
print get_id_details_2(5,2,'in.txt')
// result is None

输入文件

Customer ID: 1
Customer Name: John1
Customer Sale: 5
Customer ID: 2
Customer Name: John2
Customer Sale: 6
Customer ID: 4
Customer Name: John3
Customer Sale: 7
Customer ID: 3

在txt文件中搜索一个字符，并从其下面的一行返回一个字符

3 个答案: