cfloop: looping over a list, a file, or an array
Looping over a list steps through elements contained in any of these entities:
- A variable
- A value that is returned from an expression
- An array
- A file
Looping over a file does not open the entire file in memory.
<cfloop
index = "index name"
array = "array"
characters = "number of characters"
delimiters = "item delimiter"
file = "absolute path and filename">
list = "list items"
...
</cfloop>
cfabort, cfbreak, cfexecute, cfexit, cfif, cflocation, cfswitch, cfthrow, cftry; "cfloop and cfbreak" in the ColdFusion Developer's Guide
ColdFusion 8: Added the characters, file, and array attributes.
|
Attribute |
Req/Opt |
Default |
Description |
|---|---|---|---|
|
index |
Required |
|
In a list loop, the variable to receive the next list element. |
|
list |
Required unless you specify a filename in the file attribute |
|
A list, variable, or filename; contains a list. |
|
array |
Optional |
|
An array. |
|
characters |
Optional |
|
The number of characters to read during each iteration of the loop from the file specified in the file attribute. If the value of the characters attribute is more than the number of characters in the file, ColdFusion uses the number of characters in the file. |
|
delimiters |
Optional |
|
Characters that separate items in list. |
|
file |
Optional |
|
The absolute path and filename of the text file to read, one line at a time. This is helpful when reading large text files, because you can reuse the value of the index variable, which contains the current line of the file. When the loop completes, ColdFusion closes the file. |
This loop displays four names:
<cfloop index = "ListElement" list = "John,Paul,George,Ringo">
<cfoutput>#ListElement#</cfoutput><br>
</cfloop>
You can put more than one character in the delimiters attribute, in any order. For example, this loop processes commas, colons, and slashes as list delimiters:
<cfloop index = "ListElement" list = "John/Paul,George::Ringo" delimiters = ",:/">
<cfoutput>#ListElement#</cfoutput><br>
</cfloop>
ColdFusion skips the second and subsequent consecutive delimiters between list elements. Thus, in the example, the two colons between "George" and "Ringo" are processed as one delimiter.
To loop over each line of a file, use the tag as follows:
<cfloop file="c:\temp\simplefile.txt" index="line">
<cfoutput>#line#</cfoutput><br>
</cfloop>
To read a specified number of characters from a text file during each iteration of the loop, use the tag as follows:
<cfloop file="c:\temp\simplefile.txt" index="chars" characters="12">
<cfoutput>#chars#</cfoutput><br>
</cfloop>
When you read the following text file, ColdFusion reads 12 characters during each iteration of the loop; the result appears as follows:
|
Text file |
Result |
|---|---|
|
This is line 1. This is line 2. This is line 3. This is line 4. This is line 5. This is line 6. This is line 7. This is line 8. This is line 9. This is line 10. This is line 11. |
This is line 1. This is line 2. Th is is line 3 . This is l ine 4. This is line 5. This is lin e 6. This i s line 7. T his is line 8. This is line 9. Thi s is line 10 . This is l ine 11. |
To loop over an array, you can do the following:
<cfset x = ["mars","earth", "venus", "jupiter"]>
<cfloop array=#x# index="name">
<cfoutput>#name#</cfoutput><br>
</cfloop>