index(sub [,start [,end]]) -> int Like S.find() but raise ValueError when the substring is not found. """ return 0 def isalnum(self): """ 是否是字母和数字 """ """ S.isalnum() -> bool Return True if all characters in S are alphanumeric and there is at least one character...
Starting from Python 3.X, list comprehensions also have their own scope.▶ Rounding like a banker *Let's implement a naive function to get the middle element of a list:def get_middle(some_list): mid_index = round(len(some_list) / 2) return some_list[mid_index - 1]Python...
4.字符串的查询操作 '''index()查找第一次出现的位置 抛异常rindex()查找最后一次次出现的位置 抛异常find()查找第一次出现的位置 不抛异常,返回值为-1rfind()查找最后一次出现的位置 抛异常'''s = 'hello,hello'print(s.index('o'))print(s.rindex('o'))print(s.find('lo'))print(s.find('ui'...
return -1 if not found 366 def rfind(s, *args): 367 """rfind(s, sub [,start [,end]]) -> int 368 369 Return the highest index in s where substring sub is found, 370 such that sub is contained within s[start,end]. Optional...
2. Get Substring of a String using Slicing Slicing is a built-in Python feature that allows you to extract a substring from a string by specifying its start and end indices. The resultingstringwill include all the characters from the start index up to, but not including, the end index. ...
julia> arr2 = [1,2,3,4,5] 5-element Vector{Int64}: 1 2 3 4 5 julia> arr2[0] # 索引第0个元素报错 ERROR: BoundsError: attempt to access 5-element Vector{Int64} at index [0] Stacktrace: [1] getindex(A::Vector{Int64}, i1::Int64) @ Base ./array.jl:924 [2] top-level ...
def rfind(self, sub, start=None, end=None): # real signature unknown; restored from __doc__ (返回字符串最后一次出现的位置(从右向左查询),如果没有匹配项则返回-1) """ S.rfind(sub[, start[, end]]) -> int Return the highest index in S where substring sub is found, such that sub...
ExampleIn this example, we are slicing the string text starting at index 20. Since the length of text is only 11 characters, there is no character at index 20. Instead of giving an error, Python returns an empty string.text = "Lorem Ipsum" substring = text[20:] print(substring) ...
Return the lowest index in S where substring sub is found, such that sub is contained within S[start:end]. Optional arguments start and end are interpreted as in slice notation. Return -1 on failure. S.find(sub[, start[, end]]) -> int ...
| index(...) | S.index(sub [,start [,end]])->int | | Like S.find() butraiseValueError when the substringisnotfound. | | isalnum(...) | S.isalnum()->bool | | ReturnTrueifallcharactersinS are alphanumeric |andthereisat least one characterinS,Falseotherwise. ...