如何检查数组中的任何字符串是否存在于另一个字符串中?
例如:
a = ['a', 'b', 'c']
s = "a123"
if a in s:
print("some of the strings found in s")
else:
print("no strings found in s")
我如何替换如果a在s:行得到适当的结果?
如何检查数组中的任何字符串是否存在于另一个字符串中?
例如:
a = ['a', 'b', 'c']
s = "a123"
if a in s:
print("some of the strings found in s")
else:
print("no strings found in s")
我如何替换如果a在s:行得到适当的结果?
你可以使用任何:
a_string = "A string is more than its parts!"
matches = ["more", "wholesome", "milk"]
if any([x in a_string for x in matches]):
类似地,要检查是否找到列表中的所有字符串,请使用all而不是any。
的元素上进行迭代。
a = ['a', 'b', 'c']
str = "a123"
found_a_string = False
for item in a:
if item in str:
found_a_string = True
if found_a_string:
print "found a match"
else:
print "no match found"
a = ['a', 'b', 'c']
str = "a123"
a_match = [True for match in a if match in str]
if True in a_match:
print "some of the strings found in str"
else:
print "no strings found in str"
如果a或str中的字符串变长,您应该小心。简单的解决方案是O(S*(A^2)),其中S是str的长度,A是A中所有字符串长度的总和。要获得更快的解决方案,请查看用于字符串匹配的Aho-Corasick算法,该算法在线性时间O(S+A)内运行。
为了增加regex的多样性:
import re
if any(re.findall(r'a|b|c', str, re.IGNORECASE)):
print 'possible matches thanks to regex'
else:
print 'no matches'
或者如果你的列表太长- any(re.findall(r'|'.join(a), str, re.IGNORECASE))
如果你想要的只是True或False, any()是目前为止最好的方法,但如果你想知道具体匹配哪个字符串/字符串,你可以使用一些东西。
如果你想要第一个匹配(默认为False):
match = next((x for x in a if x in str), False)
如果你想获得所有匹配项(包括重复项):
matches = [x for x in a if x in str]
如果你想获得所有非重复的匹配(不考虑顺序):
matches = {x for x in a if x in str}
如果你想按正确的顺序获得所有非重复的匹配项:
matches = []
for x in a:
if x in str and x not in matches:
matches.append(x)
这取决于上下文 假设你想检查单个文字(任何单个单词a,e,w,..等)就足够了
original_word ="hackerearcth"
for 'h' in original_word:
print("YES")
如果你想检查original_word中的任何一个字符: 利用
if any(your_required in yourinput for your_required in original_word ):
如果您想要original_word中的所有输入,请使用所有输入 简单的
original_word = ['h', 'a', 'c', 'k', 'e', 'r', 'e', 'a', 'r', 't', 'h']
yourinput = str(input()).lower()
if all(requested_word in yourinput for requested_word in original_word):
print("yes")
为了降低复杂度,jbernadas已经提到了aho - corasick -算法。
下面是在Python中使用它的一种方法:
从这里下载aho_corasick.py 将它放在与Python主文件相同的目录中,并将其命名为aho_corasick.py 用以下代码尝试该算法: 导入aho_corasick #(字符串,关键字) Print (aho_corasick(string, ["keyword1", "keyword2"]))
注意,搜索是区分大小写的
flog = open('test.txt', 'r')
flogLines = flog.readlines()
strlist = ['SUCCESS', 'Done','SUCCESSFUL']
res = False
for line in flogLines:
for fstr in strlist:
if line.find(fstr) != -1:
print('found')
res = True
if res:
print('res true')
else:
print('res false')
为了提高速度,我会使用这样的函数:
def check_string(string, substring_list):
for substring in substring_list:
if substring in string:
return True
return False
data = "firstName and favoriteFood"
mandatory_fields = ['firstName', 'lastName', 'age']
# for each
for field in mandatory_fields:
if field not in data:
print("Error, missing req field {0}".format(field));
# still fine, multiple if statements
if ('firstName' not in data or
'lastName' not in data or
'age' not in data):
print("Error, missing a req field");
# not very readable, list comprehension
missing_fields = [x for x in mandatory_fields if x not in data]
if (len(missing_fields)>0):
print("Error, missing fields {0}".format(", ".join(missing_fields)));
只是关于如何在String中获得所有列表元素的更多信息
a = ['a', 'b', 'c']
str = "a123"
list(filter(lambda x: x in str, a))
一个惊人的快速方法是使用set:
a = ['a', 'b', 'c']
str = "a123"
if set(a) & set(str):
print("some of the strings found in str")
else:
print("no strings found in str")
如果a不包含任何多字符值(在这种情况下使用上面列出的any),则此方法有效。如果是这样,将a指定为字符串会更简单:a = 'abc'。
这是set的另一个解。使用set.intersection。对于一行代码。
subset = {"some" ,"words"}
text = "some words to be searched here"
if len(subset & set(text.split())) == len(subset):
print("All values present in text")
if subset & set(text.split()):
print("Atleast one values present in text")
python文档中推荐的regex模块支持这一点
words = {'he', 'or', 'low'}
p = regex.compile(r"\L<name>", name=words)
m = p.findall('helloworld')
print(m)
输出:
['he', 'low', 'or']
实现的一些细节:link
在另一个字符串列表中查找多个字符串的一种紧凑方法是使用set.intersection。这比大型集或列表中的列表理解执行得快得多。
>>> astring = ['abc','def','ghi','jkl','mno']
>>> bstring = ['def', 'jkl']
>>> a_set = set(astring) # convert list to set
>>> b_set = set(bstring)
>>> matches = a_set.intersection(b_set)
>>> matches
{'def', 'jkl'}
>>> list(matches) # if you want a list instead of a set
['def', 'jkl']
>>>
如果您想要单词的精确匹配,那么可以考虑对目标字符串进行单词标记。我使用nltk推荐的word_tokenize:
from nltk.tokenize import word_tokenize
下面是接受答案的标记化字符串:
a_string = "A string is more than its parts!"
tokens = word_tokenize(a_string)
tokens
Out[46]: ['A', 'string', 'is', 'more', 'than', 'its', 'parts', '!']
接受的答案修改如下:
matches_1 = ["more", "wholesome", "milk"]
[x in tokens for x in matches_1]
Out[42]: [True, False, False]
在公认的答案中,单词“more”仍然是匹配的。但是,如果“mo”成为匹配字符串,接受的答案仍然找到匹配。这是我不希望看到的行为。
matches_2 = ["mo", "wholesome", "milk"]
[x in a_string for x in matches_1]
Out[43]: [True, False, False]
使用单词标记化,“mo”不再匹配:
[x in tokens for x in matches_2]
Out[44]: [False, False, False]
这是我想要的附加行为。这个答案也回答了这里的重复问题。