51 lines
975 B
Java
51 lines
975 B
Java
// strings/JGrep.java
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// A very simple version of the "grep" program.
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// {Args: JGrep.java 'void|int|String'}
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import java.util.regex.*;
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import onjava.*;
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public class JGrep {
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public static void main(String[] args) throws Exception {
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if(args.length < 2) {
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System.out.println("Usage: java JGrep file regex");
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System.exit(0);
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}
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Pattern p = Pattern.compile(args[1]);
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// Iterate through the lines of the input file:
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int index = 0;
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Matcher m = p.matcher("");
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for(String line : new TextFile(args[0])) {
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m.reset(line);
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while(m.find())
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System.out.println(index++ + ": " +
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m.group() + ": " + m.start());
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}
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}
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}
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/* Output:
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0: 'void: 21
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1: int: 27
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2: String': 31
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3: int: 19
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4: int: 4
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5: int: 21
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6: 'void: 3
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7: int: 3
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8: String': 3
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9: int: 3
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10: int: 3
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11: int: 3
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12: 'void: 3
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13: int: 3
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14: String': 3
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15: int: 3
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16: int: 4
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17: int: 4
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18: 'void: 4
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19: int: 4
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20: String': 4
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21: int: 4
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22: int: 4
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23: int: 4
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*/
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