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CS112 Scientific Computation
Department of Computer Science
Wellesley College
Storing it away for safe keeping
Reading and writing text files
Cell arrays 16-2
Reading a text file into a cell array
Large amounts of text data can be stored in text files, with a .txt
extension, e.g. mobydick.txt
Successive lines of a text file can be read into the cells of a cell
array using the textread function.
>> lines = textread('mobydick.txt','%s','delimiter', '\n');
>> lines{1}
ans =
Call me Ishmael. Some years ago – never mind how long precisely - having
>> lines{2}
ans =
little or no money in my purse, and nothing particular to interest me on shore,
Call me Ishmael. Some years ago – never mind how long precisely – having
little or no money in my purse, and nothing particular to interest me on shor e,
I thought I would sail about a little and see the watery part of the world. It
is a way I have of driving off the spleen a nd regulating the circulation…
Cell arrays 16-3
More on textread
Suppose we have a text file elements.txt that contains
a combination of numerical data and strings, in a
fixed format
1 hydrogen H 1.01
2 helium He 4.00
3 lithium Li 6.94
4 beryllium Be 9.01
5 boron B 10.81
6 carbon C 12.01
7 nitrogen N 14.01
8 oxygen O 16.00
9 fluorine F 19.00
10 neon Ne 20.18
...
Cell arrays 16-4
Reading formatted data
The format string can incorporate other types:
>> [atomNums names symbols masses] = ...
textread('elements.txt', '%u %s %s %f');
Recall our text file elements.txt with numerical data and strings:
>> atomNums'
1 2 3 4 5 6 7 8 9 10 …
>> names'
'hydrogen' 'helium' 'lithium' 'beryllium' 'boron' 'carbon' …
>> symbols'
'H''He''Li''Be''B''C''N''O''F''Ne'…
>> masses'
1.0100 4.0000 6.9400 9.0100 10.8100 12.0100 14.0100 …
format string:
%u integer
%s string
%f float
'is the transpose operator
