Importing Null data points

Hi,

I have an ASCII data set, which includes null data points. eg

1 x1 y1 z1
2 x2 y2 z2
3 x3 y3 z3
4 y3 z3
5 y4 z4
6 y5

I am using ipython with pylab enabled, and the load("/xxx/xxx")
function. However it chokes on the blank, "null", values. How can I
get this data set into matplotlib?

Regards,

Ciarán

Ciarán Mooney wrote:

Hi,

I have an ASCII data set, which includes null data points. eg

1 x1 y1 z1
2 x2 y2 z2
3 x3 y3 z3
4 y3 z3
5 y4 z4
6 y5

I am using ipython with pylab enabled, and the load("/xxx/xxx")
function. However it chokes on the blank, "null", values. How can I
get this data set into matplotlib?

I assume the file is using fixed-length fields. I don't know of any ready-made tool for reading files with non-delimited fields, with or without gaps, so you probably have to write your own to fit your particular file. The general approach would be to read a line in as a character string, use slices to isolate the fields, try to convert each to a number, and if it fails put in a flag value. These numbers can go in a list, and as you go through the lines you accumulate the lists in a list. Then you can use numpy.ma.masked_equal(your_list_of_lists, your_flag_value) to create a 2-D masked array suitable for use by mpl.

Eric

···

Regards,

Ciarán

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