使用正则表达式验证数值范围

Question

我的输入数字是一个int。但输入数字必须在-2055到2055之间，我想通过使用正则表达式来检查。

那么无论如何要写一个正则表达式来检查一个数字是否在（-2055,2055）中？

使用if语句检查数字是否在范围内更容易。但我正在写一个解释器，所以我应该用正则表达式来检查输入数字

Answer 1

使用正则表达式验证数值范围

要明确：当一个简单的if语句就足够了

if(num < -2055  ||  num > 2055)  {
   throw  new IllegalArgumentException("num (" + num + ") must be between -2055 and 2055");
}

建议不要使用正则表达式来验证数值范围。

此外，由于正则表达式分析字符串，因此必须先将数字转换为字符串，然后才能对其进行测试。一个例外是当数字恰好是一个字符串时，例如从控制台获取用户输入时。

（为确保字符串是一个开头的数字，您可以使用org.apache.commons.lang3.math.NumberUtils#isNumber(s)）

尽管如此，弄清楚如何用正则表达式验证数字范围是有趣且有益的。

（此答案中的链接来自Stack Overflow Regular Expressions FAQ。）

一个数字范围

规则：一个数字必须正好15。

最简单的范围。与此匹配的正则表达式是

\b15\b

Word boundaries是必要的，以避免匹配15内的8215242。

两个数字范围

规则：该号码必须介于15和16之间。以下是三种可能的正则表达式：

\b(15|16)\b
\b1(5|6)\b
\b1[5-6]\b

（这些组是“或”-ing所必需的，但它们可以是non-capturing：\b(?:15|16)\b）

数字范围“镜像”在零附近

规则：号码必须介于-12和12之间。

以下为0至12的正则表达式，仅为正数：

\b(\d|1[0-2])\b

免间隔：

\b(         //The beginning of a word (or number), followed by either
   \d       //   Any digit 0 through 9
|           //Or
   1[0-2]   //   A 1 followed by any digit between 0 and 2.
)\b         //The end of a word

让这项工作既有消极也有积极，就像在开头添加optional短划线一样简单：

-?\b(\d|1[0-2])\b

（假设破折号前面没有不合适的字符。）

要禁止负数，需要negative lookbehind：

(?<!-)\b(\d|1[0-2])\b

将看外观放在一边会导致11中的-11匹配。 （这篇文章中的第一个例子应该添加这个。）

注意：\d与[0-9]

为了兼容所有正则表达式，所有\d-s should be changed to [0-9]。例如，.NET将非ASCII数字（例如不同语言的数字）视为\d的合法值。除了在最后一个示例中，为简洁起见，它保留为\d。

（感谢@TimPietzcker）

三位数，除第一位数以外的所有数字均为零

规则：必须介于0和400之间。

可能的正则表达式：

(?<!-)\b([1-3]?\d{1,2}|400)\b

自由空间：

   (?<!-)          //Something not preceded by a dash
   \b(             //Word-start, followed by either
      [1-3]?       //   No digit, or the digit 1, 2, or 3
         \d{1,2}   //   Followed by one or two digits (between 0 and 9)
   |               //Or
      400          //   The number 400
   )\b             //Word-end

永远不会被使用的另一种可能性：

\b(0|1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31|32|33|34|35|36|37|38|39|40|41|42|43|44|45|46|47|48|49|50|51|52|53|54|55|56|57|58|59|60|61|62|63|64|65|66|67|68|69|70|71|72|73|74|75|76|77|78|79|80|81|82|83|84|85|86|87|88|89|90|91|92|93|94|95|96|97|98|99|100|101|102|103|104|105|106|107|108|109|110|111|112|113|114|115|116|117|118|119|120|121|122|123|124|125|126|127|128|129|130|131|132|133|134|135|136|137|138|139|140|141|142|143|144|145|146|147|148|149|150|151|152|153|154|155|156|157|158|159|160|161|162|163|164|165|166|167|168|169|170|171|172|173|174|175|176|177|178|179|180|181|182|183|184|185|186|187|188|189|190|191|192|193|194|195|196|197|198|199|200|201|202|203|204|205|206|207|208|209|210|211|212|213|214|215|216|217|218|219|220|221|222|223|224|225|226|227|228|229|230|231|232|233|234|235|236|237|238|239|240|241|242|243|244|245|246|247|248|249|250|251|252|253|254|255|256|257|258|259|260|261|262|263|264|265|266|267|268|269|270|271|272|273|274|275|276|277|278|279|280|281|282|283|284|285|286|287|288|289|290|291|292|293|294|295|296|297|298|299|300|301|302|303|304|305|306|307|308|309|310|311|312|313|314|315|316|317|318|319|320|321|322|323|324|325|326|327|328|329|330|331|332|333|334|335|336|337|338|339|340|341|342|343|344|345|346|347|348|349|350|351|352|353|354|355|356|357|358|359|360|361|362|363|364|365|366|367|368|369|370|371|372|373|374|375|376|377|378|379|380|381|382|383|384|385|386|387|388|389|390|391|392|393|394|395|396|397|398|399|400)\b

最后的例子：四个数字，零附近镜像，不以零结尾。

规则：必须介于-2055和2055之间

这是来自堆栈溢出的question。

正则表达式：

(-?\b(?:20(?:5[0-5]|[0-4][0-9])|1[0-9]{3}|[1-9][0-9]{0,2}|(?<!-)0+))\b

Debuggex Demo

免间隔：

(             //Capture group for the entire number
   -?\b             //Optional dash, followed by a word (number) boundary
   (?:20            //Followed by "20", which is followed by one of 
         (?:5[0-5]        //50 through 55
           |                  //or
         [0-4][0-9])      //00 through 49
      |                                         //or
         1[0-9]{3}        //a one followed by any three digits
      |                                         //or
         [1-9][0-9]{0,2}  //1-9 followed by 0 through 2 of any digit
      |                                         //or
         (?<!-)0+         //one-or-more zeros *not* preceded by a dash
   )                 //end "or" non-capture group
)\b            //End number capture group, followed by a word-bound

（感谢PlasmaPower和Casimir et Hippolyte提供调试帮助。）

最后的注释

根据您的身份capturing，可能应将所有子组划分为非捕获组。例如，这：

(-?\b(?:20(?:5[0-5]|[0-4][0-9])|1?[0-9]{1,3})\b)

而不是：

-?\b(20(5[0-5]|[0-4][0-9])|1?[0-9]{1,3})\b

示例Java实现

  import  java.util.Scanner;
  import  java.util.regex.Matcher;
  import  java.util.regex.Pattern;
  import  org.apache.commons.lang.math.NumberUtils;
/**
  <P>Confirm a user-input number is a valid number by reading a string an testing it is numeric before converting it to an it--this loops until a valid number is provided.</P>

  <P>{@code java UserInputNumInRangeWRegex}</P>
 **/
public class UserInputNumInRangeWRegex  {
  public static final void main(String[] ignored)  {

     int num = -1;
     boolean isNum = false;

     int iRangeMax = 2055;

     //"": Dummy string, to reuse matcher
     Matcher mtchrNumNegThrPos = Pattern.compile("(-?\\b(?:20(?:5[0-5]|[0-4][0-9])|1[0-9]{3}|[1-9][0-9]{0,2}|(?<!-)0+))\\b").matcher("");

     do  {
        System.out.print("Enter a number between -" + iRangeMax + " and " + iRangeMax + ": ");
        String strInput = (new Scanner(System.in)).next();
        if(!NumberUtils.isNumber(strInput))  {
           System.out.println("Not a number. Try again.");
        }  else if(!mtchrNumNegThrPos.reset(strInput).matches())  {
           System.out.println("Not in range. Try again.");
        }  else  {
           //Safe to convert
           num = Integer.parseInt(strInput);
           isNum = true;
        }
     }  while(!isNum);

     System.out.println("Number: " + num);
  }

}

输出

[C:\java_code\]java UserInputNumInRangeWRegex
Enter a number between -2055 and 2055: tuhet
Not a number. Try again.
Enter a number between -2055 and 2055: 283837483
Not in range. Try again.
Enter a number between -2055 and 2055: -200000
Not in range. Try again.
Enter a number between -2055 and 2055: -300
Number: -300

此stackoverflow问题的原始答案

这是一个符合您要求的严肃答案。它类似于@ PlasmaPower的回答。

(-?\b(?:20(?:5[0-5]|[0-4][0-9])|1[0-9]{3}|[1-9][0-9]{0,2}|(?<!-)0+))\b

Debuggex Demo

Answer 2

不要使用它，但这有效。 ：）

\b(-2055|-2054|-2053|-2052|-2051|-2050|-2049|-2048|-2047|-2046|-2045|-2044|-2043|-2042|-2041|-2040|-2039|-2038|-2037|-2036|-2035|-2034|-2033|-2032|-2031|-2030|-2029|-2028|-2027|-2026|-2025|-2024|-2023|-2022|-2021|-2020|-2019|-2018|-2017|-2016|-2015|-2014|-2013|-2012|-2011|-2010|-2009|-2008|-2007|-2006|-2005|-2004|-2003|-2002|-2001|-2000|-1999|-1998|-1997|-1996|-1995|-1994|-1993|-1992|-1991|-1990|-1989|-1988|-1987|-1986|-1985|-1984|-1983|-1982|-1981|-1980|-1979|-1978|-1977|-1976|-1975|-1974|-1973|-1972|-1971|-1970|-1969|-1968|-1967|-1966|-1965|-1964|-1963|-1962|-1961|-1960|-1959|-1958|-1957|-1956|-1955|-1954|-1953|-1952|-1951|-1950|-1949|-1948|-1947|-1946|-1945|-1944|-1943|-1942|-1941|-1940|-1939|-1938|-1937|-1936|-1935|-1934|-1933|-1932|-1931|-1930|-1929|-1928|-1927|-1926|-1925|-1924|-1923|-1922|-1921|-1920|-1919|-1918|-1917|-1916|-1915|-1914|-1913|-1912|-1911|-1910|-1909|-1908|-1907|-1906|-1905|-1904|-1903|-1902|-1901|-1900|-1899|-1898|-1897|-1896|-1895|-1894|-1893|-1892|-1891|-1890|-1889|-1888|-1887|-1886|-1885|-1884|-1883|-1882|-1881|-1880|-1879|-1878|-1877|-1876|-1875|-1874|-1873|-1872|-1871|-1870|-1869|-1868|-1867|-1866|-1865|-1864|-1863|-1862|-1861|-1860|-1859|-1858|-1857|-1856|-1855|-1854|-1853|-1852|-1851|-1850|-1849|-1848|-1847|-1846|-1845|-1844|-1843|-1842|-1841|-1840|-1839|-1838|-1837|-1836|-1835|-1834|-1833|-1832|-1831|-1830|-1829|-1828|-1827|-1826|-1825|-1824|-1823|-1822|-1821|-1820|-1819|-1818|-1817|-1816|-1815|-1814|-1813|-1812|-1811|-1810|-1809|-1808|-1807|-1806|-1805|-1804|-1803|-1802|-1801|-1800|-1799|-1798|-1797|-1796|-1795|-1794|-1793|-1792|-1791|-1790|-1789|-1788|-1787|-1786|-1785|-1784|-1783|-1782|-1781|-1780|-1779|-1778|-1777|-1776|-1775|-1774|-1773|-1772|-1771|-1770|-1769|-1768|-1767|-1766|-1765|-1764|-1763|-1762|-1761|-1760|-1759|-1758|-1757|-1756|-1755|-1754|-1753|-1752|-1751|-1750|-1749|-1748|-1747|-1746|-1745|-1744|-1743|-1742|-1741|-1740|-1739|-1738|-1737|-1736|-1735|-1734|-1733|-1732|-1731|-1730|-1729|-1728|-1727|-1726|-1725|-1724|-1723|-1722|-1721|-1720|-1719|-1718|-1717|-1716|-1715|-1714|-1713|-1712|-1711|-1710|-1709|-1708|-1707|-1706|-1705|-1704|-1703|-1702|-1701|-1700|-1699|-1698|-1697|-1696|-1695|-1694|-1693|-1692|-1691|-1690|-1689|-1688|-1687|-1686|-1685|-1684|-1683|-1682|-1681|-1680|-1679|-1678|-1677|-1676|-1675|-1674|-1673|-1672|-1671|-1670|-1669|-1668|-1667|-1666|-1665|-1664|-1663|-1662|-1661|-1660|-1659|-1658|-1657|-1656|-1655|-1654|-1653|-1652|-1651|-1650|-1649|-1648|-1647|-1646|-1645|-1644|-1643|-1642|-1641|-1640|-1639|-1638|-1637|-1636|-1635|-1634|-1633|-1632|-1631|-1630|-1629|-1628|-1627|-1626|-1625|-1624|-1623|-1622|-1621|-1620|-1619|-1618|-1617|-1616|-1615|-1614|-1613|-1612|-1611|-1610|-1609|-1608|-1607|-1606|-1605|-1604|-1603|-1602|-1601|-1600|-1599|-1598|-1597|-1596|-1595|-1594|-1593|-1592|-1591|-1590|-1589|-1588|-1587|-1586|-1585|-1584|-1583|-1582|-1581|-1580|-1579|-1578|-1577|-1576|-1575|-1574|-1573|-1572|-1571|-1570|-1569|-1568|-1567|-1566|-1565|-1564|-1563|-1562|-1561|-1560|-1559|-1558|-1557|-1556|-1555|-1554|-1553|-1552|-1551|-1550|-1549|-1548|-1547|-1546|-1545|-1544|-1543|-1542|-1541|-1540|-1539|-1538|-1537|-1536|-1535|-1534|-1533|-1532|-1531|-1530|-1529|-1528|-1527|-1526|-1525|-1524|-1523|-1522|-1521|-1520|-1519|-1518|-1517|-1516|-1515|-1514|-1513|-1512|-1511|-1510|-1509|-1508|-1507|-1506|-1505|-1504|-1503|-1502|-1501|-1500|-1499|-1498|-1497|-1496|-1495|-1494|-1493|-1492|-1491|-1490|-1489|-1488|-1487|-1486|-1485|-1484|-1483|-1482|-1481|-1480|-1479|-1478|-1477|-1476|-1475|-1474|-1473|-1472|-1471|-1470|-1469|-1468|-1467|-1466|-1465|-1464|-1463|-1462|-1461|-1460|-1459|-1458|-1457|-1456|-1455|-1454|-1453|-1452|-1451|-1450|-1449|-1448|-1447|-1446|-1445|-1444|-1443|-1442|-1441|-1440|-1439|-1438|-1437|-1436|-1435|-1434|-1433|-1432|-1431|-1430|-1429|-1428|-1427|-1426|-1425|-1424|-1423|-1422|-1421|-1420|-1419|-1418|-1417|-1416|-1415|-1414|-1413|-1412|-1411|-1410|-1409|-1408|-1407|-1406|-1405|-1404|-1403|-1402|-1401|-1400|-1399|-1398|-1397|-1396|-1395|-1394|-1393|-1392|-1391|-1390|-1389|-1388|-1387|-1386|-1385|-1384|-1383|-1382|-1381|-1380|-1379|-1378|-1377|-1376|-1375|-1374|-1373|-1372|-1371|-1370|-1369|-1368|-1367|-1366|-1365|-1364|-1363|-1362|-1361|-1360|-1359|-1358|-1357|-1356|-1355|-1354|-1353|-1352|-1351|-1350|-1349|-1348|-1347|-1346|-1345|-1344|-1343|-1342|-1341|-1340|-1339|-1338|-1337|-1336|-1335|-1334|-1333|-1332|-1331|-1330|-1329|-1328|-1327|-1326|-1325|-1324|-1323|-1322|-1321|-1320|-1319|-1318|-1317|-1316|-1315|-1314|-1313|-1312|-1311|-1310|-1309|-1308|-1307|-1306|-1305|-1304|-1303|-1302|-1301|-1300|-1299|-1298|-1297|-1296|-1295|-1294|-1293|-1292|-1291|-1290|-1289|-1288|-1287|-1286|-1285|-1284|-1283|-1282|-1281|-1280|-1279|-1278|-1277|-1276|-1275|-1274|-1273|-1272|-1271|-1270|-1269|-1268|-1267|-1266|-1265|-1264|-1263|-1262|-1261|-1260|-1259|-1258|-1257|-1256|-1255|-1254|-1253|-1252|-1251|-1250|-1249|-1248|-1247|-1246|-1245|-1244|-1243|-1242|-1241|-1240|-1239|-1238|-1237|-1236|-1235|-1234|-1233|-1232|-1231|-1230|-1229|-1228|-1227|-1226|-1225|-1224|-1223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Answer 3

分析问题

如果你＆＃34;必须＆＃34;使用正则表达式，通过分析已接受的排列来解决问题。

＆＃34;范围从-2055到2055＆＃34;可表示为：

• 可选 -
• 可选前导零
• 后跟0到2055之间的数字

＆＃34; 0到2055之间的数字＆＃34;可以是有限数量的特定排列之一：

• 一位数（0-9）
• 两位数（10-99）
• 三位数（100-999）
• 以1（1000-1999）
开头的四位数字
• 以20（2000-204 * 9）
开头的四位数字
• 以205（2050-2055 *）
开头的四位数字

请注意，出于此正则表达式的目的，没有必要区分范围＆＃34; 0-9＆＃34;和＆＃34; 1-9＆＃34;，只有最后两个范围对接受的数字/字符范围有任何限制（用星号表示）。

编写组件正则表达式

上述每个组成部分都易于单独表达为正则表达式：

• -
• 0 *
  • [0-9]
  • [0-9] [0-9]
  • [0-9] [0-9] [0-9]
  • 1 [0-9] [0-9] [0-9]
  • 20 [0-4] [0-9]
  • 205 [0-5]

将表达式放在一起

整场比赛的相关表达式为：

-?0*([0-9]|[0-9][0-9]|[0-9][0-9][0-9]|1[0-9][0-9][0-9]|20[0-4][0-9]|205[0-5])

或稍微简洁一点：

-?0*([0-9]{1,3}|1[0-9]{3}|20[0-4][0-9]|205[0-5])

假设输入仅包含＆＃34;数字＆＃34;没有别的，因此最终的正则表达式是：

^-?0*([0-9]{1,3}|1[0-9]{3}|20[0-4][0-9]|205[0-5])$

如果需要允许前导加号，则变为：

^[-+]?0*([0-9]{1,3}|1[0-9]{3}|20[0-4][0-9]|205[0-5])$

Here's a js fiddle展示了最后一个正则表达式传递的内容和失败的内容。

Answer 4

答案很多，但是没有人在评论中读到（或关心）OPs方面的问题？

  

我正在OCaml中编写一个解释器....如何验证输入   在不使用正则表达式的范围内的数字？ - Trung Nguyen 3月2日   在17:30

正如许多答案 - 正确地 - 指出使用正则表达式对于这种情况来说是可怕的，让我们考虑OCaml中的其他方法！我使用OCaml已经有一段时间了，但是通过查找一些结构，我能够将它们组合在一起：

let isInRange i = 
    not(i < -2055 or i > 2055);;

let isIntAndInRange s = 
    try
    let i = int_of_string s in
    not(i < -2055 or i > 2055)
    with Failure "int_of_string" -> false;;

let () = print_string "type a number: " in
let s = read_line () in
isIntAndInRange s

如果有任何不明之处，请阅读其语法type conversion functions和exception handling以及input-output functions。

用户输入部分仅用于演示。在那里使用read_int函数可能更方便。但处理异常的基本概念保持不变。

Answer 5

为什么只使用Regex检查一个数字？

int n = -2000;

if(n >= -2055 && n <= 2055)
//Do something
else
//Do something else

Answer 6

作为aliteralmind提供的伟大表达的另一种方法，这里有一个更长但有趣的方法，以便看到另一种方法可能看起来像（以及什么不该做）。

这是一项有趣的练习，因为你可以想到两种不同的方法：粗略地说，你可以：

1. 继续匹配4-char数字，然后是3-char数字等
2. 或继续匹配千位数字，然后是数百位数字等。

不试试，你怎么知道哪个最好？事实证明，第一种方法（aliteralmind的回答）更为经济。

降低，我在PHP语言中包含一系列测试，以防您或其他人想检查输出。

下面，我将在＆＃34;自由间隔模式＆＃34;中为您提供正则表达式，它允许在正则表达式中进行注释，以便您可以轻松了解它的作用。然而，并非所有的正则表达式引擎都支持自由间隔模式，所以在我们开始讨论有趣的部分之前，这里的正则表达式是一个单行程序。

请注意，您的问题提到了从-2055到2055的数字。我认为您希望匹配＆＃34;正常数字＆＃34;，没有前导零。这意味着正则表达式将匹配999而不是0999.如果你想要领先零，请告诉我，这是一个非常容易的调整。

此外，如果您在utf-8模式下进行匹配，则\d应替换为[0-9]。这是更常见的形式。

正则表达式作为单一航线

^(?!-0$)-?(?:(?=\d{4}$)[12])?(?:(?=\d{3}$)(?:(?:(?<=^)|(?<=^-)|(?<=1)|(?<=-1))\d|(?:(?<=2)|(?<=-2))0))?(?:(?=\d{2}$)(?:(?:(?<=^)|(?<=^-)|(?<=^\d)|(?<=^-\d)|(?<=^\d{2})(?<!20)|(?<=^-\d{2})(?<!-20))\d|(?:(?<=20)|(?<=-20))[0-5]))?(?:(?=\d$)(?:(?:(?<=^)|(?<=^-)|(?<=^\d)|(?<=^-\d)|(?<=^\d{2})|(?<=^-\d{2})|(?<=^\d{3})(?<!205)|(?<=^-\d{3})(?<!-205))\d|(?:(?<=205)|(?<=-205))[0-5]))$

自由间隔模式下的正则表达式

(?x)                # free-spacing mode
^                   # anchor at beginning of string.
(?!-0$)-?           # optional minus sign, but not for -0

(?:                 # OPTIONAL THOUSANDS DIGIT
(?=\d{4}$)[12]      # assert that the number is 4-digit long, match 1 or 2
)?                  # end optional thousands digit


(?:                 # OPTIONAL HUNDREDS DIGIT
(?=\d{3}$)          # assert that there are three digits left
(?:                 # non-capturing group
  (?:(?<=^)|(?<=^-)|(?<=1)|(?<=-1))\d    # if preceding chars are 1, -1 or head of string: value can be any digit
  |                      # or
  (?:(?<=2)|(?<=-2))0                # if preceding chars are 2 or -2: value must be 0
)                   # close non-capturing group
)?                  # end optional hundreds digits

(?:             # OPTIONAL TENS DIGIT
(?=\d{2}$)      # assert that there are two digits left
(?:             # start non-capturing group

                # if preceding char is head of string, single digit,
                # or two digits that are not 20
                # (with or without a minus)
                # value can be any digit
  (?:(?<=^)|(?<=^-)|(?<=^\d)|(?<=^-\d)|
     (?<=^\d{2})(?<!20)|(?<=^-\d{2})(?<!-20))\d  
|               # or
(?:(?<=20)|(?<=-20))[0-5]  # if preceding chars are 20 or -20: value can be from 0 to 5

)               # end non-capturing group
)?              # close optional tens digits

(?:             # FINAL DIGIT (non optional)
(?=\d$)         # assert that there is only one digit left
(?:             # start non-capturing group

                # if preceding char is head of string, single digit, 
                # two digits, or three digits that are not 205
                # (with or without a minus)
                # value can be any digit
  (?:(?<=^)|(?<=^-)|(?<=^\d)|(?<=^-\d)|
      (?<=^\d{2})|(?<=^-\d{2})|
      (?<=^\d{3})(?<!205)|(?<=^-\d{3})(?<!-205))
      \d
  |             # or
  (?:(?<=205)|(?<=-205))[0-5] # if preceding chars are 205 or -205: value can be from 0 to 5
)               # end non-capturing group
)               # end final digit
$

系列测试

这些测试尝试匹配-100000到100000之间的数字。它们产生以下输出：

Successful test: matches from -2055 to 2055
Successful test: NO matches from -100000 to -2056
Successful test: NO matches from 2056 to 100000

以下是代码：

<?php
$regex="~^(?!-0$)-?(?:(?=\d{4}$)[12])?(?:(?=\d{3}$)(?:(?:(?<=^)|(?<=^-)|(?<=1)|(?<=-1))\d|(?:(?<=2)|(?<=-2))0))?(?:(?=\d{2}$)(?:(?:(?<=20)|(?<=-20))[0-5]|(?:(?<=^)|(?<=^-)|(?<=^\d)|(?<=^-\d)|(?<=^\d{2})(?<!20)|(?<=^-\d{2})(?<!-20))\d))?(?:(?=\d$)(?:(?:(?<=205)|(?<=-205))[0-5]|(?:(?<=^)|(?<=^-)|(?<=^\d)|(?<=^-\d)|(?<=^\d{2})|(?<=^-\d{2})|(?<=^\d{3})(?<!205)|(?<=^-\d{3})(?<!-205))\d))$~";

// Test 1
$success="Successful test: matches from -2055 to 2055";
for($i=-2055;$i<=2055;$i++) {
$chari = sprintf("%d",$i);
if (! preg_match($regex,$chari)) {
    $success="Failed test: matches from -2055 to 2055";
    echo $chari.": No Match!<br />";
    }
}
echo $success."<br />";

// Test 2
$success="Successful test: NO matches from -100000 to -2056";
for($i=-100000;$i<=-2056;$i++) {
$chari = sprintf("%d",$i);
if (preg_match($regex,$chari)) {
    $success="Failed test: NO matches from -100000 to -2056";
    echo $chari.": Match!<br />";
    }
}
echo $success."<br />";

// Test 3
$success="Successful test: NO matches from 2056 to 100000";
for($i=2056;$i<=100000;$i++) {
$chari = sprintf("%d",$i);
if (preg_match($regex,$chari)) {
    $success="Failed test: NO matches from 2056 to 100000";
    echo $chari.": Match!<br />";
    }
}
echo $success."<br />";

?>

速度测试

这是我的简单速度测试的输出，匹配从-1M到+ 1M。正如Casimir指出的那样，如果aliteralmind的表达被锚定，而不是更慢，那么它会更快25％！

zx81: 3.796217918396
aliteralmind: 3.9922280311584
difference: 5.1632998151294 percent longer

这是测试代码：

$regex="~(?x)^(?!-0$)-?(?:(?=\d{4}$)[12])?(?:(?=\d{3}$)(?:(?:(?<=^)|(?<=^-)|(?<=1)|(?<=-1))\d|(?:(?<=2)|(?<=-2))0))?(?:(?=\d{2}$)(?:(?:(?<=^)|(?<=^-)|(?<=^\d)|(?<=^-\d)|(?<=^\d{2})(?<!20)|(?<=^-\d{2})(?<!-20))\d|(?:(?<=20)|(?<=-20))[0-5]))?(?:(?=\d$)(?:(?:(?<=^)|(?<=^-)|(?<=^\d)|(?<=^-\d)|(?<=^\d{2})|(?<=^-\d{2})|(?<=^\d{3})(?<!205)|(?<=^-\d{3})(?<!-205))\d|(?:(?<=205)|(?<=-205))[0-5]))$~";

$regex2 = "~(-?\b(?:20(?:5[0-5]|[0-4][0-9])|1[0-9]{3}|[1-9][0-9]{0,2}|(?<!-)0+))\b~";

$start=microtime(TRUE);
for ($i=-1000000;$i<1000000;$i++) preg_match($regex,$i);
$zxend=microtime(TRUE);
for ($i=-1000000;$i<1000000;$i++) preg_match($regex2,$i);
$alitend=microtime(TRUE);
$zx81 = $zxend-$start;
$alit = $alitend-$zxend;
$diff = 100*($alit-$zx81)/$zx81;
echo "zx81: ".$zx81."<br />";
echo "aliteralmind: ".$alit."<br />";
echo "difference: ".$diff." percent longer<br />";

Answer 7

试试这个：

\-?\b0*(205[0-5]|20[0-4]\d|1?\d{3}|\d{1,2})\b

Answer 8

查看这个为数字范围生成正则表达式的优秀工具：

http://gamon.webfactional.com/regexnumericrangegenerator/

对于OP请求的范围，它会生成：-?([0-9]{1,3}|1[0-9]{3}|20[0-4][0-9]|205[0-5])

Answer 9

尝试非常简单的正则表达式。

^([-0][0-1][0-9][0-9][0-9])$|^([-0]20[0-4][0-9])$|^([-0]205[0-5])$

视觉表现

非常简单易懂。

• 第1组[-0][0-1][0-9][0-9][0-9]将涵盖 [ - 1999,1999] 值
• 第2组[-0]20[0-4][0-9]将涵盖 [ - 2000，-2049] 和 [2000,2049] 值
• 第3组[-0]205[0-5]将涵盖 [ - 2050，-2055] 和 [2050,2055] 值

  

String.format("%05d", number)在这里做得很好吗？

示例代码:(读取内联注释以获得更清晰。）

int[] numbers = new int[] { -10002, -3000, -2056, -2055, -2000, -1999, -20, 
                            -1,  0, 1, 260, 1999, 2000, 2046, 2055, 2056, 2955, 
                             3000, 10002, 123456 };

//valid range -2055 to 2055 inclusive

Pattern p = Pattern.compile("^([-0][0-1][0-9][0-9][0-9])$|^([-0]20[0-4][0-9])$|^([-0]205[0-5])$");

for (int number : numbers) {
    String string = String.format("%05d", number);
    Matcher m = p.matcher(string);

    if (m.find()) {
        System.out.println(number + " is in range.");
    } else {
        System.out.println(number + " is not in range.");
    }
}

输出：

-10002 is not in range.
-3000 is not in range.
-2056 is not in range.
-2055 is in range.
-2000 is in range.
-1999 is in range.
-20 is in range.
-1 is in range.
0 is in range.
1 is in range.
260 is in range.
1999 is in range.
2000 is in range.
2046 is in range.
2055 is in range.
2056 is not in range.
2955 is not in range.
3000 is not in range.
10002 is not in range.
123456 is not in range.

Answer 10

试试这个：

^-?0*(1?[0-9]{1,3}|20[0-4][0-9]|205[0-5])$

括号前的正则表达式与可选的-和任何前导0匹配。

括号中的第一部分（1?[0-9]{1,3}）匹配0-1999。

括号中的第二部分（20[0-4][0-9]）符合2000-2049。

括号中的第三部分（205[0-5]）与2050-2055匹配。

Answer 11

又一个 -

 #  ^-?0*(?:20(?:[0-4][0-9]|5[0-5])|[0-9]{1,3})$

 ^ 
 -?
 0*
 (?:
      20
      (?:
           [0-4] [0-9] 
        |  
           5 [0-5] 
      )
   |  
      [0-9]{1,3} 
 )
 $