In order to avoid thisTraceback Error, we can use the keywordinto check if a substring is contained in a string. In the case of Loops, it was used for iteration, whereas in this case it’s a conditional that can be eithertrueorfalse.It’ll be true if the substring is part of the ...
ValueError: substring not found >>> str.index("n") #同find类似,返回第一次匹配的索引值 4 >>> str.rindex("n") #返回最后一次匹配的索引值 11 >>> str.count('a') #字符串中匹配的次数 0 >>> str.count('n') #同上 2 >>> str.replace('EAR','ear') #匹配替换 'string learn' >...
rindex('o', 8)) # ValueError: substring not found 性质判断 可以通过字符串的startswith、endswith来判断字符串是否以某个字符串开头和结尾;还可以用is开头的方法判断字符串的特征,这些方法都返回布尔值,代码如下所示。 s1 = 'hello, world!' print(s1.startswith('He')) # False print(s1.startswith...
main_string ="I learned English and Python with ZHouluobo. You can do it too!" # Index 0 print(main_string[0]) # Index 1 print(main_string[1]) # Check if Index 1 is whitespace print(main_string[1].isspace) # Slicing 1 print(main_string[0:11]) # Slicing 2: print(main_string...
How to check if substring exists ? if "substring" in test_string: if s.startswith(("a", "b")): 6. Expressions — Python 3.7.2rc1 documentation - Membership test operations https://docs.python.org/3/reference/expressions.html#membership-test-details Built-in Types — Python 3.7.2rc1 ...
mapping Unicode ordinals to Unicode ordinals, strings, or None. If this operation raises LookupError, the character is left untouched. Characters mapped to None are deleted. 案例: 用字符的maketrans() 和 translate() 实现凯撒加密算法 string.ascii_letters ...
main_string="I learned English and Python with ZHouluobo. You can do it too!"# Index 0print(main_string[0])# Index 1print(main_string[1])# Check if Index 1 is whitespaceprint(main_string[1].isspace())# Slicing 1print(main_string[0:11])# Slicing 2:print(main_string[-18:])# ...
join(<coll_of_strings>) # Joins elements using string as a separator. <bool> = in <str> # Checks if string contains the substring. <bool> = <str>.startswith() # Pass tuple of strings for multiple options. <int> = <str>.find() # Returns start index of the first match or -...
if file_p.find('一直会被删除的') == 0 and os.path.exists(file_path): os.remove(file_p) 1. 2. if file_p.find('一直会被删除的') != -1 and os.path.exists(file_path): os.remove(file_p) 1. 2. 字符串开头、结尾 startswith() \endwith() ...
join(<coll_of_strings>) # Joins elements using string as separator. <bool> = in <str> # Checks if string contains a substring. <bool> = <str>.startswith() # Pass tuple of strings for multiple options. <bool> = <str>.endswith() # Pass tuple of strings for multiple options. <i...