【Python】Java转Python的一些水土不服

regular expression

java

String text = "你好啊，我的名字叫Ethan Hunt";
text = text.replaceAll("(.*?)([a-zA-Z]+)(.*?)", "$1<$2>$3");
System.out.println(text);

python

import re
text = '你好啊，我的名字叫Ethan Hunt'.decode('utf-8')
regex = re.sub(ur'(.*?)([a-z_A-Z]+)(.*?)', ur'\1<\2>\3', text)
print regex

你好啊，我的名字叫<Ethan> <Hunt>

import re
regex = re.compile(ur'(.*?)([a-z_A-Z]+)(.*?)')
for content in some_file:
content = regex.sub(ur'\1<\2>\3', content)

String.substring

text = 'Hello World'
print text[6:]

World

String.charAt

text = 'Hello World'
print text[1]

e

class toString

class Pair:
def __init__(self, a, b):
self.a = a
self.b = b

def __repr__(self):
return '<Pair a:%d b:%d>' % (self.a, self.b)

def __str__(self):
return 'str <Pair a:%d b:%d>' % (self.a, self.b)

p = Pair(1, 2)
print p
print repr(p)
print str(p)
lst = [p]
print lst

str <Pair a:1 b:2>
<Pair a:1 b:2>
str <Pair a:1 b:2>
[<Pair a:1 b:2>]

获取文件所在目录的上一级目录

import os
os.path.abspath(os.path.join(os.path.dirname(__file__),os.path.pardir))

编码问题：csv - CSV File Reading and Writing

import csv, codecs, cStringIO

class UTF8Recoder:
"""
Iterator that reads an encoded stream and reencodes the input to UTF-8
"""
def __init__(self, f, encoding):
self.reader = codecs.getreader(encoding)(f)

def __iter__(self):
return self

def next(self):
return self.reader.next().encode("utf-8")

class UnicodeReader:
"""
A CSV reader which will iterate over lines in the CSV file "f",
which is encoded in the given encoding.
"""

def __init__(self, f, dialect=csv.excel, encoding="utf-8", **kwds):
f = UTF8Recoder(f, encoding)
self.reader = csv.reader(f, dialect=dialect, **kwds)

def next(self):
row = self.reader.next()
return [unicode(s, "utf-8") for s in row]

def __iter__(self):
return self

class UnicodeWriter:
"""
A CSV writer which will write rows to CSV file "f",
which is encoded in the given encoding.
"""

def __init__(self, f, dialect=csv.excel, encoding="utf-8", **kwds):
# Redirect output to a queue
self.queue = cStringIO.StringIO()
self.writer = csv.writer(self.queue, dialect=dialect, **kwds)
self.stream = f
self.encoder = codecs.getincrementalencoder(encoding)()

def writerow(self, row):
self.writer.writerow([s.encode("utf-8") for s in row])
# Fetch UTF-8 output from the queue ...
data = self.queue.getvalue()
data = data.decode("utf-8")
# ... and reencode it into the target encoding
data = self.encoder.encode(data)
# write to the target stream
self.stream.write(data)
# empty queue
self.queue.truncate(0)

def writerows(self, rows):
for row in rows:
self.writerow(row)