How to find the first decimal number in a string ?

5883 · 08-08-2013, 05:02 PM

looking for a simple 1 line solution,

e.g.
tmpfs 200 5 195 2% /tmp

it should return 200.

thanks !

danielbmartin · 08-08-2013, 05:24 PM

This is one way ...

With this InFile ...

Code:

tmpfs 200 5 195 2% /tmp
151 367 how now brown cow
ab98def four five six 789 happy

... this awk ...

Code:

awk '{for (j=1;j<=NF;j++) if ($j+0==$j) {print $j; break}}' $InFile >$OutFile

... produced this OutFile ...

Code:

200
151
789

Daniel B. Martin

PTrenholme · 08-08-2013, 06:18 PM

Note that Mr. Martin's solution will pick out the first field that parses to any valid number, not just integer numbers.

Code:

$ cat inFile 
tmpfs 200 5 195 2% /tmp
151 367 how now brown cow
ab98def four five six 789 happy
1e5 7 19
one two 3.14159 e
1.4test 2.4

$ awk '{for (j=1;j<=NF;j++) if ($j+0==$j) {print $j; break}}' inFile
200
151
789
1e5
3.14159
2.4

danielbmartin · 08-08-2013, 06:48 PM

Quote:

Originally Posted by PTrenholme

Note that Mr. Martin's solution will pick out the first field that parses to any valid number, not just integer numbers.

Quite right. OP asked for "the first decimal number." The definition of decimal number includes 200, 151, 789, 1e5, 3.14159, 2.4, and many others.

Daniel B. Martin