Question

脚本 :

import re

matches = [ hello ,  hey ,  hi ,  hiya ]

def check_match(string):
    for item in matches:
        if re.search(item, string):
            print  Match found:   + string
        else:
            print  Match not found:   + string

check_match( hey )
check_match( hello there )
check_match( this should not match )
check_match( oh, hiya )

产出:

Match not found: hey
Match found: hey
Match not found: hey
Match not found: hey
Match found: hello there
Match not found: hello there
Match not found: hello there
Match not found: hello there
Match not found: this should not match
Match not found: this should not match
Match found: this should not match
Match not found: this should not match
Match not found: oh, hiya
Match not found: oh, hiya
Match found: oh, hiya
Match found: oh, hiya

有些事情我不明白。首先,每个字符串在这个输出中被搜索了四次,有些返回两个作为发现匹配,有些返回三个。我不确定导致这种情况的代码有什么问题,但有人能尝试看出什么问题吗?

预期产出如下:

Match found: hey
Match found: hello there
Match not found: this should not match
Match found: oh, hiya

Answer 1

它并非行为错误,而是你对 re.search(...) 的误解。

参见输出后的评论:

Match not found: hey                    # because  hello  is not in  hey 
Match found: hey                        # because  hey  is in  hey 
Match not found: hey                    # because  hi  is not in  hey 
Match not found: hey                    # because  hiya  is not in  hey 

Match found: hello there                # because  hello  is in  hello there 
Match not found: hello there            # because  hey  is not in  hello there 
Match not found: hello there            # because  hi  is not in  hello there 
Match not found: hello there            # because  hiya  is not in  hello there 

Match not found: this should not match  # because  hello  is not in  this should not match 
Match not found: this should not match  # because  hey  is not in  this should not match 
Match found: this should not match      # because  hi  is in  this should not match 
Match not found: this should not match  # because  hiya  is not in  this should not match 

Match not found: oh, hiya               # because  hello  is not in  oh, hiya 
Match not found: oh, hiya               # because  hey  is not in  oh, hiya 
Match found: oh, hiya                   # because  hi  is in  oh, hiya 
Match found: oh, hiya                   # because  hiya  is in  oh, hiya

如果您不想在输入 oh, hiya 时匹配模式 < hihi , 您应该围绕您的模式环绕单词边界 :



hi


它只会导致它匹配由其它字母包围的 hi  <%em> not  ( well hiya there  与模式 不符,但  wellhi there  将 ) 。

Answer 2

尝试这个 - 它更简洁, 它会显示多重匹配 :

import re

matches = [ hello ,  hey ,  hi ,  hiya ]

def check_match(string):
    results = [item for item in matches if re.search(r %s  % (item), string)]
    print  Found %s  % (results) if len(results) > 0 else "No match found"

check_match( hey )
check_match( hello there )
check_match( this should not match )
check_match( oh, hiya )
check_match( xxxxx xxx )
check_match( hello and hey )

给予 :

Found [ hey ]
Found [ hello ]
No match found
Found [ hiya ]
No match found
Found [ hello ,  hey ]

Answer 3

您为每组获得 4 个搜索和 4 个输出, 因为您正在通过一个阵列循环, 搜索并输出数组中每个元素的某个内容...

Answer 4

循环是检查每个匹配点的字符串, 打印出来是否为每个匹配点找到。您真正想要的是看到匹配点中是否有匹配点, 然后打印出一个“ 找到” 或“ 未找到 ” 。我其实不知道 python, 所以语法可能关闭。

for item in matches:
    if re.search(item, string):
    found = true
if found:
    print  Match found:   + string
else:
    print  Match not found:   + string

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