Conditionals in awk

Fatipati

3/3/24, 5:28 PM

In bash I can do the shortcut condition for an if statement

  (( globrl == 1 )) && var=val

Is there something equivalent in awk, without having to use a direct if condition ?

118

1 + 5

awk

Raffa

3/3/24, 5:32 PM

Yes `echo "2 3" | awk '($2 == 3) {print $2}'` or as compact as `echo "2 3" | awk '$2==3{print $2}'` ... Can be also something like `echo "2 3" | awk '/3/{print $1}'`

Fatipati

3/3/24, 5:34 PM

Ok, so I can use `globrl == 1 { var = val }` then

Raffa

3/3/24, 5:36 PM

Yep ........... The whole concept of `awk` processing is a set of conditions and actions.

Fatipati

3/3/24, 5:38 PM

I like it.......

Fatipati

3/3/24, 6:27 PM

A top level construct ? Can it be used inside an awk function, testing a local variable?

Score:1

Ubuntu

Raffa

3/3/24, 5:44 PM

Yes, ...

# If the second field is "3" print it
$ echo "2 3" | awk '{if ($2 == 3) print $2}'
3

# If the second field is "3" print it
$ echo "2 3" | awk '($2 == 3) {print $2}'
3

# If the second field is "3" print it
$ echo "2 3" | awk '$2==3{print $2}'
3

# If a match for "3" is in a line print the first field of this line
$ echo "2 3" | awk '/3/{print $1}'
2

# If the second field is "3" assign the value of "4" to the variable var then print it
$ echo "2 3" | awk '$2==3{var=4; print var}'
4

# If the second field is "3" assign the value of "yes" to the variable var or otherwise assign "no" to it and print it
$ echo "2 3" | awk 'var = $2 == 3 ? "yes" : "no" {print var}'
yes

# If the second field is "2" assign the value of "yes" to the variable var or otherwise assign "no" to it and print it
$ echo "2 3" | awk 'var=$2==2?"yes":"no"{print var}'
no

# Same as the above but utilizing the conditional expression with the ternary operator ‘?:’  in a function
$ echo "2 3" | awk 'function myfunc(field){var = field == 2 ? "yes" : "no"}; myfunc($2); {print var}'
no

+ 3

Fatipati

3/3/24, 7:03 PM

Could these commands be used inside an awk function?

Raffa

3/3/24, 7:06 PM

@Backy No, ... Functions have `{...}` as main grouping constructs ... Conditions and actions inside them can be in the form `if (...) ...`

Raffa

3/3/24, 8:08 PM

@Backy You can however utilize a conditional expression using the ternary operator `?:` in a function ... I have added an example for this one to the answer.

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