bash: iterate over list of floating numbers

Question

In bash script, I want to iterate over a list of values that I want to pass as parameters to a script in python. It turns out that $d and $minFreq aren't floats when passed to the python script. Why does this happen?

for d in {0.01, 0.05, 0.1} do for i in {1..3} do someString=`python scrpt1.py -f myfile --delta $d --counter $i| tail -1` for minFreq in {0.01, 0.02} do for bValue in {10..12} do python testNEW.py $someString -d $bValue $minFreq done done done done

Lose the spaces around the equals sign in the someString = $(python ...) line (with back-ticks replaced by $(...) because getting back-ticks into a comment as back-ticks is tricky, at best. — Jonathan Leffler
– Jonathan Leffler, Commented Aug 10, 2012 at 13:34

Jonathan Leffler · Accepted Answer · 2012-08-10 15:36:03Z

30

Either remove the spaces

for d in {0.01,0.05,0.1}

or don't use the {} expansion (it's not necessary here):

for d in 0.01 0.05 0.1

The same applies to the minFreq loop.

As written,

for d in {0.01, 0.05, 0.1}

the variable d is assigned the literal string values {0.01,, 0.05,, and 0.1}.

edited Aug 10, 2012 at 15:36

Jonathan Leffler

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answered Aug 10, 2012 at 13:13

chepner

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2 Comments

Jonathan Leffler Over a year ago

While the spaces in the expansion are unnecessary, the Python process should not see them at all, I think. I'd expect the shell to remove the spaces when constructing the argument list since the shell variables are not quoted.

chepner Over a year ago

The spaces prevent brace expansion from taking place, so the braces and commas are not syntax, but included in the strings passed to python.

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