"""A collection of string operations (most are no longer used). Warning: most of the code you see here isn't normally used nowadays. Beginning with Python 1.6, many of these functions are implemented as methods on the standard string object. They used to be implemented by a built-in module called strop, but strop is now obsolete itself. Public module variables: whitespace -- a string containing all characters considered whitespace lowercase -- a string containing all characters considered lowercase letters uppercase -- a string containing all characters considered uppercase letters letters -- a string containing all characters considered letters digits -- a string containing all characters considered decimal digits hexdigits -- a string containing all characters considered hexadecimal digits octdigits -- a string containing all characters considered octal digits punctuation -- a string containing all characters considered punctuation printable -- a string containing all characters considered printable """
# Case conversion helpers # Use str to convert Unicode literal in case of -U l = map(chr, xrange(256)) _idmap = str('').join(l) del l
# Functions which aren't available as string methods.
# Capitalize the words in a string, e.g. " aBc dEf " -> "Abc Def". defcapwords(s, sep=None): """capwords(s [,sep]) -> string 用split拆分参数转换为单词，利用capitalize使单词首字母大写，并且用join连接这些单词。 如果可选的第二个参数sep是缺省或无，以单个空格代替一串空白字符串， 开头和结尾的空格被删除，否则以sep为分隔符来分割和连接单词. 如string.capwords(" nice to meet you "),输出为：Nice To Meet You 如string.capwords(" niceto meet you ","e"),输出为： niceTo meeT you Split the argument into words using split, capitalize each word using capitalize, and join the capitalized words using join. If the optional second argument sep is absent or None, runs of whitespace characters are replaced by a single space and leading and trailing whitespace are removed, otherwise sep is used to split and join the words. """ return (sep or' ').join(x.capitalize() for x in s.split(sep))
# Construct a translation string _idmapL = None defmaketrans(fromstr, tostr): """maketrans(frm, to) -> string 返回一个转换表适用于string.translate使用（字符串长256字节）。字符串frm和to必须具有相同的长度 Return a translation table (a string of 256 bytes long) suitable for use in string.translate. The strings frm and to must be of the same length. """ if len(fromstr) != len(tostr): raise ValueError, "maketrans arguments must have same length" global _idmapL ifnot _idmapL: _idmapL = list(_idmap) L = _idmapL[:] fromstr = map(ord, fromstr) for i in range(len(fromstr)): L[fromstr[i]] = tostr[i] return''.join(L)
#################################################################### import re as _re
class_multimap: """Helper class for combining multiple mappings. Used by .{safe_,}substitute() to combine the mapping and keyword arguments. """ def__init__(self, primary, secondary): self._primary = primary self._secondary = secondary
# Search for $$, $identifier, ${identifier}, and any bare $'s
def_invalid(self, mo): i = mo.start('invalid') lines = self.template[:i].splitlines(True) ifnot lines: colno = 1 lineno = 1 else: colno = i - len(''.join(lines[:-1])) lineno = len(lines) raise ValueError('Invalid placeholder in string: line %d, col %d' % (lineno, colno))
defsubstitute(*args, **kws): ifnot args: raise TypeError("descriptor 'substitute' of 'Template' object " "needs an argument") self, args = args[0], args[1:] # allow the "self" keyword be passed if len(args) > 1: raise TypeError('Too many positional arguments') ifnot args: mapping = kws elif kws: mapping = _multimap(kws, args[0]) else: mapping = args[0] # Helper function for .sub() defconvert(mo): # Check the most common path first. named = mo.group('named') or mo.group('braced') if named isnotNone: val = mapping[named] # We use this idiom instead of str() because the latter will # fail if val is a Unicode containing non-ASCII characters. return'%s' % (val,) if mo.group('escaped') isnotNone: return self.delimiter if mo.group('invalid') isnotNone: self._invalid(mo) raise ValueError('Unrecognized named group in pattern', self.pattern) return self.pattern.sub(convert, self.template)
defsafe_substitute(*args, **kws): ifnot args: raise TypeError("descriptor 'safe_substitute' of 'Template' object " "needs an argument") self, args = args[0], args[1:] # allow the "self" keyword be passed if len(args) > 1: raise TypeError('Too many positional arguments') ifnot args: mapping = kws elif kws: mapping = _multimap(kws, args[0]) else: mapping = args[0] # Helper function for .sub() defconvert(mo): named = mo.group('named') or mo.group('braced') if named isnotNone: try: # We use this idiom instead of str() because the latter # will fail if val is a Unicode containing non-ASCII return'%s' % (mapping[named],) except KeyError: return mo.group() if mo.group('escaped') isnotNone: return self.delimiter if mo.group('invalid') isnotNone: return mo.group() raise ValueError('Unrecognized named group in pattern', self.pattern) return self.pattern.sub(convert, self.template)
#################################################################### # NOTE: Everything below here is deprecated. Use string methods instead. # This stuff will go away in Python 3.0.
# convert UPPER CASE letters to lower case deflower(s): """lower(s) -> string 返回字符串s转换为小写的副本。 Return a copy of the string s converted to lowercase. """ return s.lower()
# Convert lower case letters to UPPER CASE defupper(s): """upper(s) -> string 返回字符串s转换为大写的副本。 Return a copy of the string s converted to uppercase. """ return s.upper()
# Swap lower case letters and UPPER CASE defswapcase(s): """swapcase(s) -> string 返回的字符串s的副本,大写字符转换为小写，反之亦然。 Return a copy of the string s with upper case characters converted to lowercase and vice versa. """ return s.swapcase()
# Strip leading and trailing tabs and spaces defstrip(s, chars=None): """strip(s [,chars]) -> string 返回字符串s的副本，开头和结尾的空格去掉。 如果chars给出，删除s开头和结尾的chars字符串，如string.strip("as1asdgas","as"),输出为：1asdg Return a copy of the string s with leading and trailing whitespace removed. If chars is given and not None, remove characters in chars instead. If chars is unicode, S will be converted to unicode before stripping. """ return s.strip(chars)
# Strip leading tabs and spaces deflstrip(s, chars=None): """lstrip(s [,chars]) -> string 返回的字符串s的副本,开头空格删除。 如果字符给出，而不是None，删除s开头的chars字符串。如string.lstrip("as1asdgas","as"),输出为：1asdgas Return a copy of the string s with leading whitespace removed. If chars is given and not None, remove characters in chars instead. """ return s.lstrip(chars)
# Strip trailing tabs and spaces defrstrip(s, chars=None): """rstrip(s [,chars]) -> string 返回的字符串s的副本,结尾空格删除。 如果字符给出，而不是None，删除s结尾的chars字符串。如string.rstrip("as1asdgas","as"),输出为：as1asdg Return a copy of the string s with trailing whitespace removed. If chars is given and not None, remove characters in chars instead. """ return s.rstrip(chars)
# Split a string into a list of space/tab-separated words defsplit(s, sep=None, maxsplit=-1): """split(s [,sep [,maxsplit]]) -> list of strings 返回字符串s中单词的列表，用sep作为字符串的分隔符。如果maxsplit给出，分割在不超过第 maxsplit个分隔符的位置（结果至多为maxsplit+ 1个单词）。如果sep未指定或为None，以空白字符串作为分隔符。 如string.split("a ds sd"),输出为['a','ds','sd'] string.split("a ds sd",maxsplit=1),输出为['a','ds sd'] Return a list of the words in the string s, using sep as the delimiter string. If maxsplit is given, splits at no more than maxsplit places (resulting in at most maxsplit+1 words). If sep is not specified or is None, any whitespace string is a separator. (split and splitfields are synonymous) """ return s.split(sep, maxsplit) splitfields = split
# Split a string into a list of space/tab-separated words defrsplit(s, sep=None, maxsplit=-1): """rsplit(s [,sep [,maxsplit]]) -> list of strings 返回字符串s中单词的列表，用sep作为字符串的分隔符,分割符从字符串s尾部开始算起。如果maxsplit给出，分割在不超过第 maxsplit个分隔符的位置（结果至多为maxsplit+ 1个单词）。如果sep未指定或为None，以空白字符串作为分隔符。 如string.rsplit("a ds sd"),输出为['a','ds','sd'] string.rsplit("a ds sd",maxsplit=1),输出为['a ds','sd'] Return a list of the words in the string s, using sep as the delimiter string, starting at the end of the string and working to the front. If maxsplit is given, at most maxsplit splits are done. If sep is not specified or is None, any whitespace string is a separator. """ return s.rsplit(sep, maxsplit)
# Join fields with optional separator defjoin(words, sep = ' '): """join(list [,sep]) -> string 返回列表中的单词所组成字符串，以sep相串联。默认的分隔符是一个空格。 如string.join(["nice","to", "meet","you"])，输出为：nice to meet you Return a string composed of the words in list, with intervening occurrences of sep. The default separator is a single space. (joinfields and join are synonymous) """ return sep.join(words) joinfields = join
# Find substring, raise exception if not found defindex(s, *args): """index(s, sub [,start [,end]]) -> int 类似find，但是没有找到子串时引发ValueError错误。返回子串出现的首位置，否则报错。 如string.index("a sd fg a","a"),输出为：0 如string.index("a sd fg a fg","sdsdfg"[4:5]),输出为:5 Like find but raises ValueError when the substring is not found. """ return s.index(*args)
# Find last substring, raise exception if not found defrindex(s, *args): """rindex(s, sub [,start [,end]]) -> int 类似rfind，但是没有找到子串时引发ValueError错误。返回子串出现的最后位置，否则报错。 如string.rindex("a sd fg a","a"),输出为：8 如string.rindex("a sd fg a fg","sdsdfg"[4:5]),输出为:10 Like rfind but raises ValueError when the substring is not found. """ return s.rindex(*args)
# Count non-overlapping occurrences of substring defcount(s, *args): """count(s, sub[, start[,end]]) -> int 返回字符串s[start:end]中的子串sub出现的次数.可选参数start和end都解释为片符号。 如string.count("a sd fg a","a"),输出为2 如string.count("a sd fg a fg","sdsdfg"[2:3]),输出为:1 Return the number of occurrences of substring sub in string s[start:end]. Optional arguments start and end are interpreted as in slice notation. """ return s.count(*args)
# Find substring, return -1 if not found deffind(s, *args): """find(s, sub [,start [,end]]) -> int 返回子串出现的首位置，子串包含在s[start,end]中(即子串sub长度不超过s).可选参数start和end都解释为片符号。不存在是返回-1 如string.find("a sd fg a","a"),输出为：0 如string.find("a sd fg a fg","sdsdfg"[4:5]),输出为:5 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. """ return s.find(*args)
# Find last substring, return -1 if not found defrfind(s, *args): """rfind(s, sub [,start [,end]]) -> int 返回子串出现的最后位置，子串包含在s[start,end]中(即子串sub长度不超过s).可选参数start和end都解释为片符号。不存在是返回-1 如string.rfind("a sd fg a","a"),输出为：8 如string.rfind("a sd fg a fg","sdsdfg"[4:5]),输出为:10 Return the highest 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. """ return s.rfind(*args)
# for a bit of speed _float = float _int = int _long = long
# Convert string to float defatof(s): """atof(s) -> float Return the floating point number represented by the string s. """ return _float(s)
# Convert string to integer defatoi(s , base=10): """atoi(s [,base]) -> int Return the integer represented by the string s in the given base, which defaults to 10. The string s must consist of one or more digits, possibly preceded by a sign. If base is 0, it is chosen from the leading characters of s, 0 for octal, 0x or 0X for hexadecimal. If base is 16, a preceding 0x or 0X is accepted. """ return _int(s, base)
# Convert string to long integer defatol(s, base=10): """atol(s [,base]) -> long Return the long integer represented by the string s in the given base, which defaults to 10. The string s must consist of one or more digits, possibly preceded by a sign. If base is 0, it is chosen from the leading characters of s, 0 for octal, 0x or 0X for hexadecimal. If base is 16, a preceding 0x or 0X is accepted. A trailing L or l is not accepted, unless base is 0. """ return _long(s, base)
# Left-justify a string defljust(s, width, *args): """ljust(s, width[, fillchar]) -> string 返回s的左对齐的版本，在该场指定宽度，可以根据需要用空格填充。该字符串不会被截断。如果指定了fillchar,以此代替空格。 如string.ljust(" adf", 8,"s"),输出为： adfssss 如string.ljust(" adfsfsfsfa", 3,"s"),(体现出不被截断)输出为 adfsfsfsfa Return a left-justified version of s, in a field of the specified width, padded with spaces as needed. The string is never truncated. If specified the fillchar is used instead of spaces. """ return s.ljust(width, *args)
# Right-justify a string defrjust(s, width, *args): """rjust(s, width[, fillchar]) -> string 返回s的右对齐的版本，在该场指定宽度，可以根据需要用空格填充。该字符串不会被截断。如果指定了fillchar,以此代替空格。 如string.rjust(" adf", 8,"s"),输出为：ssss adf 如string.rjust(" adfsfsfsfa", 3,"s"),(体现出不被截断)输出为 adfsfsfsfa Return a right-justified version of s, in a field of the specified width, padded with spaces as needed. The string is never truncated. If specified the fillchar is used instead of spaces. """ return s.rjust(width, *args)
# Center a string defcenter(s, width, *args): """center(s, width[, fillchar]) -> string 返回s的中心对齐的版本，在该场指定宽度，可以根据需要用空格填充。该字符串不会被截断。如果指定了fillchar,以此代替空格。 如string.center(" adf", 9,"s"),输出为：sss adfss 如string.center(" adfsfsfsfa", 3,"s"),(体现出不被截断)输出为 adfsfsfsfa Return a center version of s, in a field of the specified width. padded with spaces as needed. The string is never truncated. If specified the fillchar is used instead of spaces. """ return s.center(width, *args)
# Zero-fill a number, e.g., (12, 3) --> '012' and (-3, 3) --> '-03' # Decadent feature: the argument may be a string or a number # (Use of this is deprecated; it should be a string as with ljust c.s.) defzfill(x, width): """zfill(x, width) -> string 在字符串x左边，填充0达到指定的宽度。该字符串x不会被截断。 如string.zfill(" adf", 9),输出为：00000 adf Pad a numeric string x with zeros on the left, to fill a field of the specified width. The string x is never truncated. """ ifnot isinstance(x, basestring): x = repr(x) return x.zfill(width)
# Expand tabs in a string. # Doesn't take non-printing chars into account, but does understand \n. defexpandtabs(s, tabsize=8): """expandtabs(s [,tabsize]) -> string 返回字符串s的副本，所有的制表符(tab)由适当数量的空格替代，取决于当前列和制表符大小（默认为8） Return a copy of the string s with all tab characters replaced by the appropriate number of spaces, depending on the current column, and the tabsize (default 8). """ return s.expandtabs(tabsize)
# Character translation through look-up table. deftranslate(s, table, deletions=""): """translate(s,table [,deletions]) -> string 返回字符串s的副本，可选参数deletions出现的所有字符被删除，剩下的字符通过给定的转换表来映射， 转换表必须是长度为256的字符串.deletions不允许Unicode字符串 如t=string.maketrans('abc','ABC'),string.translate("abc123",t,'12'),输出为：ABC3 Return a copy of the string s, where all characters occurring in the optional argument deletions are removed, and the remaining characters have been mapped through the given translation table, which must be a string of length 256. The deletions argument is not allowed for Unicode strings. """ if deletions or table isNone: return s.translate(table, deletions) else: # Add s[:0] so that if s is Unicode and table is an 8-bit string, # table is converted to Unicode. This means that table *cannot* # be a dictionary -- for that feature, use u.translate() directly. return s.translate(table + s[:0])
# Capitalize a string, e.g. "aBc dEf" -> "Abc def". defcapitalize(s): """capitalize(s) -> string 返回字符串s的副本，只有首字符大写 Return a copy of the string s with only its first character capitalized. """ return s.capitalize()
# Substring replacement (global) defreplace(s, old, new, maxreplace=-1): """replace (str, old, new[, maxreplace]) -> string 返回字符串str的副本，以子串new代替所有出现的子串old。如果可选参数maxreplace给出，只有第一个maxreplace出现的地方被替换 如string.replace("old ffa old fsda old", "old", "new",2),输出为：new ffa new fsda old Return a copy of string str with all occurrences of substring old replaced by new. If the optional argument maxreplace is given, only the first maxreplace occurrences are replaced. """ return s.replace(old, new, maxreplace)
# Try importing optional built-in module "strop" -- if it exists, # it redefines some string operations that are 100-1000 times faster. # It also defines values for whitespace, lowercase and uppercase # that match <ctype.h>'s definitions.
try: from strop import maketrans, lowercase, uppercase, whitespace letters = lowercase + uppercase except ImportError: pass# Use the original versions
######################################################################## # the Formatter class # see PEP 3101 for details and purpose of this class
# The hard parts are reused from the C implementation. They're exposed as "_" # prefixed methods of str and unicode.
# The overall parser is implemented in str._formatter_parser. # The field name parser is implemented in str._formatter_field_name_split
defvformat(self, format_string, args, kwargs): used_args = set() result = self._vformat(format_string, args, kwargs, used_args, 2) self.check_unused_args(used_args, args, kwargs) return result
def_vformat(self, format_string, args, kwargs, used_args, recursion_depth): if recursion_depth < 0: raise ValueError('Max string recursion exceeded') result = [] for literal_text, field_name, format_spec, conversion in \ self.parse(format_string):
# output the literal text if literal_text: result.append(literal_text)
# if there's a field, output it if field_name isnotNone: # this is some markup, find the object and do # the formatting
# given the field_name, find the object it references # and the argument it came from obj, arg_used = self.get_field(field_name, args, kwargs) used_args.add(arg_used)
# do any conversion on the resulting object obj = self.convert_field(obj, conversion)
# expand the format spec, if needed format_spec = self._vformat(format_spec, args, kwargs, used_args, recursion_depth-1)
# format the object and append to the result result.append(self.format_field(obj, format_spec))
defconvert_field(self, value, conversion): # do any conversion on the resulting object if conversion isNone: return value elif conversion == 's': return str(value) elif conversion == 'r': return repr(value) raise ValueError("Unknown conversion specifier {0!s}".format(conversion))
# returns an iterable that contains tuples of the form: # (literal_text, field_name, format_spec, conversion) # literal_text can be zero length # field_name can be None, in which case there's no # object to format and output # if field_name is not None, it is looked up, formatted # with format_spec and conversion and then used defparse(self, format_string): return format_string._formatter_parser()
# given a field_name, find the object it references. # field_name: the field being looked up, e.g. "0.name" # or "lookup[3]" # used_args: a set of which args have been used # args, kwargs: as passed in to vformat defget_field(self, field_name, args, kwargs): first, rest = field_name._formatter_field_name_split()
obj = self.get_value(first, args, kwargs)
# loop through the rest of the field_name, doing # getattr or getitem as needed for is_attr, i in rest: if is_attr: obj = getattr(obj, i) else: obj = obj[i]