Iterating over a Nested List and Changing Values

Question

I have tried to find this answer, but can only find it in pieces which I'm having trouble putting together.

Assume I have:

aList = [["Monday", "2.03","4.03"],["Tuesday","4.03","5.03"],["Wednesday","3.2","4.3"]]

I would like to iterate over this nested list and change the numbered string values to floats.

root · Accepted Answer · 2013-02-13 08:23:47Z

8

aList = [["Monday", "2.03","4.03"],
         ["Tuesday","4.03","5.03"],
         ["Wednesday","3.2","4.3"]]

def helper(s):
    try: return float(s)
    except ValueError: return s

aList[:] = [[helper(item) for item in subl] for subl in aList]
print aList

out:

[['Monday', 2.03, 4.03], ['Tuesday', 4.03, 5.03], ['Wednesday', 3.2, 4.3]]

answered Feb 13, 2013 at 8:23

root

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Comments

alijsh · Accepted Answer · 2013-02-13 08:24:06Z

1

for item in aList:
    item[1] = float(item[1])
    item[2] = float(item[2])

answered Feb 13, 2013 at 8:24

alijsh

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1 Comment

Sergii Kozlov Over a year ago

This ans is simpler and more pythonic. Of course if we sure in data

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