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### Convert string list to number list

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```On importing a space delimited text file,  I have an extracted list of zero-padded two-digit integers in the form: Amylist{"00", "01", "02", "03", "04", "05", "06", "07", "08", "09", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23"}  How do I convert these to real numbers or integers? Thanks - Kurt  I have reviewed the Mathematica documentation and a few books looking for the equivalent of a simple string-to-number function like vba's "Value".  Could not find an answer. Thanks.

```
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```On Jan 17, 11:34 pm, Canopus56 <canopu...@yahoo.com> wrote:
> On importing a space delimited text file,  I have an extracted list of
zero-padded two-digit integers in the form: Amylist{"00", "01", "02", "03",
"04", "05", "06", "07", "08", "09", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23"}  How do I convert these to
real numbers or integers? Thanks - Kurt  I have reviewed the Mathematica
documentation and a few books looking for the equivalent of a simple string-to-number function like vba's "Value".  Could not find an answer. Thanks .

ToExpression[list] will work.

Or you could implement a stricter version:

Replace[
Characters[list] /. Table[ToString[i] -> i, {i, 0, 9}],
{valid : {__Integer} :> FromDigits[valid], _ -> \$Failed},
{1}
]

```
 0

```
Hi,

if you do not want it to convert on input, you may still use e.g.

ToExpression:

ToExpression@{"00", "01", "02", "03", "04", "05", "06", "07"}

Daniel

Canopus56 wrote:

> On importing a space delimited text file,  I have an extracted list of zero-padded two-digit integers in the form: Amylist{"00", "01", "02", "03", "04", "05", "06", "07", "08", "09", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23"}  How do I convert these to real numbers or integers? Thanks - Kurt  I have reviewed the Mathematica documentation and a few books looking for the equivalent of a simple string-to-number function like vba's "Value".  Could not find an answer. Thanks.

>

```
 0

```Am 18.01.2010 08:34, schrieb Canopus56:
> On importing a space delimited text file,  I have an extracted list
> of zero-padded two-digit integers in the form: Amylist{"00", "01",
> "02", "03", "04", "05", "06", "07", "08", "09", "10", "11", "12",
> "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23"}
> How do I convert these to real numbers or integers? Thanks - Kurt  I
> have reviewed the Mathematica documentation and a few books looking
> for the equivalent of a simple string-to-number function like vba's
> "Value".  Could not find an answer. Thanks.
>

The function you are looking for is called ToExpression. You need to map
it to your list of strings:

amylist={"02", "03", "04", "05", "06", "07", "08", "09"}

Map[ToExpression,amylist]

or abbreviated:

ToExpression /@ amylist

hth,

albert

```
 0

```Thanks to all who replied.  Even with ToExpression, I was trouble getting the string to numeric conversion to persistently take when replacing to a list. There was some weird runtime error where you could run and get:

lstTriple =lstTriple/.{x_,y_,z_}->{x,ToExpression[y],z}

lstTriple;

NumericQ[listTriple[[3,2]]]
True

lstTriple;

NumericQ[listTriple[[3,2]]]
False

After splitting out the column containing numeric string data explicitly to a new single variable list, then running the Map function using ToExpression, and then reassembling the list triple, would Mathematica recognize the numeric and not string format persistently.

Thanks again for the help. - Kurt

----- Original Message ----
From: dh <dh@metrohm.com>
To: Canopus56 <canopus56@yahoo.com>
Sent: Mon, January 18, 2010 4:06:33 AM
Subject: Re: Convert string list to number list

Hi,
if you do not want it to convert on input, you may still use e.g. ToExpression:
ToExpression@{"00", "01", "02", "03", "04", "05", "06", "07"}
Daniel

Canopus56 wrote:
> On importing a space delimited text file,  I have an extracted list of zero-padded two-digit integers in the form: Amylist{"00", "01", "02", "03", "04", "05", "06", "07", "08", "09", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23"}  How do I convert these to real numbers or integers? Thanks - Kurt  I have reviewed the Mathematica documentation and a few books looking for the equivalent of a simple string-to-number function like vba's "Value".  Could not find an answer. Thanks.

```
 0

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