Modifying List Input (1)

Reading Free-Format Data

Modifying List Input

You can make list input more versatile by using modified list input. There are two modifiers that can be used with list input.

The ampersand (&) modifier is used to read character values that contain embedded blanks.
The colon (:) modifier is used to read nonstandard data values and character values longer than eight characters, but without embedded blanks.

You can use modified list input to read the file shown below. This file contains the names of the ten largest U.S. cities ranked in order based on their 1986 estimated population figures.

Notice that some of the values for city names contain embedded blanks. Also, note that the values representing the population of each city are nonstandard numeric values (they contain commas).

Raw Data File Topten

1---+----10---+----20---+--
1 NEW YORK 7,262,700
2 LOS ANGELES 3,259,340
3 CHICAGO 3,009,530
4 HOUSTON 1,728,910
5 PHILADELPHIA 1,642,900
6 DETROIT 1,086,220
7 SAN DIEGO 1,015,190
8 DALLAS 1,003,520
9 SAN ANTONIO 914,350
10 PHOENIX 894,070

In the following sections you will learn how to use the ampersand (&) modifier to read the values for city (City). Then you will learn how the colon (:) modifier can be used to read the nonstandard numeric values representing population (Pop86).