将Perl转换为Python

这是一个非常直译的方法,只需要最少的明显样式更改(将所有代码放入一个函数中,尽可能使用字符串而不是重新操作)。

import re, fileinput

def main():
  for line in fileinput.input():
    process = False
    for nope in ('BEGIN TRANSACTION','COMMIT',
                 'sqlite_sequence','CREATE UNIQUE INDEX'):
      if nope in line: break
    else:
      process = True
    if not process: continue
    m = re.search('CREATE TABLE "([a-z_]*)"(.*)', line)
    if m:
      name, sub = m.groups()
      line = '''DROP TABLE IF EXISTS %(name)s;
CREATE TABLE IF NOT EXISTS %(name)s%(sub)s
'''
      line = line % dict(name=name, sub=sub)
    else:
      m = re.search('INSERT INTO "([a-z_]*)"(.*)', line)
      if m:
        line = 'INSERT INTO %s%s\n' % m.groups()
        line = line.replace('"', r'\"')
        line = line.replace('"', "'")
    line = re.sub(r"([^'])'t'(.)", r"\1THIS_IS_TRUE\2", line)
    line = line.replace('THIS_IS_TRUE', '1')
    line = re.sub(r"([^'])'f'(.)", r"\1THIS_IS_FALSE\2", line)
    line = line.replace('THIS_IS_FALSE', '0')
    line = line.replace('AUTOINCREMENT', 'AUTO_INCREMENT')
    print line,

main()

Alex Martelli's solution above

在使用正则表达式替换的行中,匹配组的插入必须是双转义的,或者替换字符串必须以r作为前缀,以将is标记为正则表达式:

line = re.sub(r"([^'])'t'(.)", "\\1THIS_IS_TRUE\\2", line)

或

line = re.sub(r"([^'])'f'(.)", r"\1THIS_IS_FALSE\2", line)

此外,打印前应添加此行:

line = line.replace('AUTOINCREMENT', 'AUTO_INCREMENT')

  sub = sub.replace('"','`')

以下是经过修改的完整脚本:

import re, fileinput

def main():
  for line in fileinput.input():
    process = False
    for nope in ('BEGIN TRANSACTION','COMMIT',
                 'sqlite_sequence','CREATE UNIQUE INDEX'):
      if nope in line: break
    else:
      process = True
    if not process: continue
    m = re.search('CREATE TABLE "([a-z_]*)"(.*)', line)
    if m:
      name, sub = m.groups()
      sub = sub.replace('"','`')
      line = '''DROP TABLE IF EXISTS %(name)s;
CREATE TABLE IF NOT EXISTS %(name)s%(sub)s
'''
      line = line % dict(name=name, sub=sub)
    else:
      m = re.search('INSERT INTO "([a-z_]*)"(.*)', line)
      if m:
        line = 'INSERT INTO %s%s\n' % m.groups()
        line = line.replace('"', r'\"')
        line = line.replace('"', "'")
    line = re.sub(r"([^'])'t'(.)", "\\1THIS_IS_TRUE\\2", line)
    line = line.replace('THIS_IS_TRUE', '1')
    line = re.sub(r"([^'])'f'(.)", "\\1THIS_IS_FALSE\\2", line)
    line = line.replace('THIS_IS_FALSE', '0')
    line = line.replace('AUTOINCREMENT', 'AUTO_INCREMENT')
    if re.search('^CREATE INDEX', line):
        line = line.replace('"','`')
    print line,

main()

这是一个稍微好一点的版本。

#! /usr/bin/perl
use strict;
use warnings;
use 5.010; # for s/\K//;

while( <> ){
  next if m'
    BEGIN TRANSACTION   |
    COMMIT              |
    sqlite_sequence     |
    CREATE UNIQUE INDEX
  'x;

  if( my($name,$sub) = m'CREATE TABLE \"([a-z_]*)\"(.*)' ){
    # remove "
    $sub =~ s/\"//g; #"
    $_ = "DROP TABLE IF EXISTS $name;\nCREATE TABLE IF NOT EXISTS $name$sub\n";

  }elsif( /INSERT INTO \"([a-z_]*)\"(.*)/ ){
    $_ = "INSERT INTO $1$2\n";

    # " => \"
    s/\"/\\\"/g; #"
    # " => '
    s/\"/\'/g; #"

  }else{
    # '' => \'
    s/\'\'/\\\'/g; #'
  }

  # 't' => 1
  s/[^\\']\K\'t\'/1/g; #'

  # 'f' => 0
  s/[^\\']\K\'f\'/0/g; #'

  s/AUTOINCREMENT/AUTO_INCREMENT/g;
  print;
}

PRAGMA foreign_keys=OFF;
BEGIN TRANSACTION;
CREATE TABLE Filename (
  FilenameId INTEGER,
  Name TEXT DEFAULT '',
  PRIMARY KEY(FilenameId) 
  );
INSERT INTO "Filename" VALUES(1,'');
INSERT INTO "Filename" VALUES(2,'bigfile1');
INSERT INTO "Filename" VALUES(3,'%gconf-tree.xml');

没有人能够将“table\u name”重新格式化为正确的mysql的“table\u name”。一些人搞乱了空字符串值。

<> 被称为菱形操作符。 s/// 是替换运算符,并且 // 是火柴接线员吗 m// .

基于 http://docs.python.org/dev/howto/regex.html

1. 代替 $line =~ /.*/ 具有 re.search(r".*", line)
2. $line !~ /.*/ 只是 !($line =~ /.*/) .
3. $line =~ s/.*/x/g line=re.sub(r".*", "x", line) .
4. 代替 $1 通过 $9 re.sub 具有 \1 通过 \9 分别地
5. 在子对象外部,保存返回值,即。 m=re.search() $1 返回值为 m.group(1)
6. 对于 "INSERT INTO $1$2\n" 具体来说,你可以这样做 "INSERT INTO %s%s\n" % (m.group(1), m.group(2)) .

真正的问题是您知道如何迁移数据库吗?所呈现的只是一个搜索和替换循环。