01-11-2019
awk works in a way that it reads one input record (one line by default), executes the entire script on that line, and the proceeds to the next record.
In command 1, for every single input line you are summing up all fields in that line into a scalar variable, and then print (and reset) that variable.
In command 2, in lieu of using a scalar variable, you are using an array (indicated by the square brackets) indexed by the field No. to sum up the respective fields' values for ALL input lines, and print the sums in the END section.
See the difference now? Good reading is man awk.
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Hello,
I am trying to use AWK to print only the first field of numerous text files, and then overwrite these files. They are of the format 1*2,3,4,5. I have tried the following code (using tcsh):
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Hey,
I know this is a stupid question, but it doesn't work.
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I have two files which I would like to compare and then manipulate in a way.
File1:
pictures.txt 1.1 1.3
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Hello,
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AABBCC
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FALEF
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Here's my code:
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BEGIN
-------- <some code here>
END{
----------<some code here>
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{
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}
-----
}
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LEARN ABOUT OPENDARWIN
foreach
foreach(n) Tcl Built-In Commands foreach(n)
__________________________________________________________________________________________________________________________________________________
NAME
foreach - Iterate over all elements in one or more lists
SYNOPSIS
foreach varname list body
foreach varlist1 list1 ?varlist2 list2 ...? body
_________________________________________________________________
DESCRIPTION
The foreach command implements a loop where the loop variable(s) take on values from one or more lists. In the simplest case there is one
loop variable, varname, and one list, list, that is a list of values to assign to varname. The body argument is a Tcl script. For each
element of list (in order from first to last), foreach assigns the contents of the element to varname as if the lindex command had been
used to extract the element, then calls the Tcl interpreter to execute body.
In the general case there can be more than one value list (e.g., list1 and list2), and each value list can be associated with a list of
loop variables (e.g., varlist1 and varlist2). During each iteration of the loop the variables of each varlist are assigned consecutive
values from the corresponding list. Values in each list are used in order from first to last, and each value is used exactly once. The
total number of loop iterations is large enough to use up all the values from all the value lists. If a value list does not contain enough
elements for each of its loop variables in each iteration, empty values are used for the missing elements.
The break and continue statements may be invoked inside body, with the same effect as in the for command. Foreach returns an empty string.
EXAMPLES
The following loop uses i and j as loop variables to iterate over pairs of elements of a single list. set x {} foreach {i j} {a b c d e f}
{
lappend x $j $i } # The value of x is "b a d c f e" # There are 3 iterations of the loop.
The next loop uses i and j to iterate over two lists in parallel. set x {} foreach i {a b c} j {d e f g} {
lappend x $i $j } # The value of x is "a d b e c f {} g" # There are 4 iterations of the loop.
The two forms are combined in the following example. set x {} foreach i {a b c} {j k} {d e f g} {
lappend x $i $j $k } # The value of x is "a d e b f g c {} {}" # There are 3 iterations of the loop.
SEE ALSO
for(n), while(n), break(n), continue(n)
KEYWORDS
foreach, iteration, list, looping
Tcl foreach(n)