Originally developed for Wizard, ReadStat is a command-line tool and MIT-licensed C library for reading files from popular stats packages. Supported formats include:
- R: RData and RDS
- SAS: SAS7BDAT and SAS7BCAT
- Stata: DTA
- SPSS: POR and SAV
There is also write support for the DTA and SAV formats. At the moment, the ReadStat command-line tool works only with the non-R formats.
Bootstrap autotools by running ./autogen.sh and then proceed as usual:
./configure
make
sudo make install
Standard usage:
readstat <input file> <output file>
Where:
<input file>ends with.dta,.por,.sav, or.sas7bdat, and<output file>ends with.dtaor.sav
Note that ReadStat will not overwrite existing files, so if you get a "File exists" error, delete the file you intend to replace.
If you have a SAS catalog file containing the data set's value labels, a second invocation style is supported:
readstat <input file> <catalog file> <output file>
Where:
<input file>ends with.sas7bdat<catalog file>ends with.sas7bcat<output file>ends with.dtaor.sav
If the file conversion succeeds, ReadStat will report the number of rows and variables converted, e.g.
Converted 111 variables and 160851 rows in 12.36 seconds
At the moment value labels are supported, but the finer nuances of converting
format strings (e.g. %8.2g) are not.
The ReadStat API is callback-based. It uses very little memory, and is suitable for programs with progress bars. ReadStat uses iconv to automatically transcode text data into UTF-8, so you don't have to worry about character encodings.
See src/readstat.h for the complete API. In general you'll provide a filename and a set of optional callback functions for handling various information and data found in the file. It's up to the user to store this information in an appropriate data structure. If a context pointer is passed to the parse_* functions, it will be made available to the various callback functions.
Callback functions should return 0 on success. Returning a non-zero value will abort the parsing process.
Example: Return the number of records in a DTA file.
#include "readstat.h"
int handle_info(int obs_count, int var_count, void *ctx) {
int *my_count = (int *)ctx;
*my_count = obs_count;
return 0;
}
int main(int argc, char *argv[]) {
if (argc != 2) {
printf("Usage: %s <filename>\n", argv[0]);
return 1;
}
int my_count = 0;
readstat_error_t error = READSTAT_OK;
readstat_parser_t *parser = readstat_parser_init();
readstat_set_info_handler(parser, &handle_info);
error = readstat_parse_dta(parser, argv[1], &my_count);
readstat_parser_free(parser);
if (error != READSTAT_OK) {
printf("Error processing %s: %d\n", argv[1], error);
return 1;
}
printf("Found %d records\n", my_count);
return 0;
}Example: Convert a DTA to a tab-separated file.
#include "readstat.h"
int handle_info(int obs_count, int var_count, void *ctx) {
int *my_var_count = (int *)ctx;
*my_var_count = var_count;
return 0;
}
int handle_variable(int index, readstat_variable_t *variable,
const char *val_labels, void *ctx) {
int *my_var_count = (int *)ctx;
printf("%s", readstat_variable_get_name(variable));
if (index == *my_var_count - 1) {
printf("\n");
} else {
printf("\t");
}
return 0;
}
int handle_value(int obs_index, int var_index, readstat_value_t value, void *ctx) {
int *my_var_count = (int *)ctx;
readstat_types_t type = readstat_value_type(value);
if (!readstat_value_is_missing(value)) {
if (type == READSTAT_TYPE_STRING) {
printf("%s", readstat_string_value(value));
} else if (type == READSTAT_TYPE_CHAR) {
printf("%hhd", readstat_char_value(value));
} else if (type == READSTAT_TYPE_INT16) {
printf("%hd", readstat_int16_value(value));
} else if (type == READSTAT_TYPE_INT32) {
printf("%d", readstat_int32_value(value));
} else if (type == READSTAT_TYPE_FLOAT) {
printf("%f", readstat_float_value(value));
} else if (type == READSTAT_TYPE_DOUBLE) {
printf("%lf", readstat_double_value(value));
}
}
if (var_index == *my_var_count - 1) {
printf("\n");
} else {
printf("\t");
}
return 0;
}
int main(int argc, char *argv[]) {
if (argc != 2) {
printf("Usage: %s <filename>\n", argv[0]);
return 1;
}
int my_var_count = 0;
readstat_error_t error = READSTAT_OK;
readstat_parser_t *parser = readstat_parser_init();
readstat_set_info_handler(parser, &handle_info);
readstat_set_variable_handler(parser, &handle_variable);
readstat_set_value_handler(parser, &handle_value);
error = readstat_parse_dta(parser, argv[1], &my_var_count);
readstat_parser_free(parser);
if (error != READSTAT_OK) {
printf("Error processing %s: %d\n", argv[1], error);
return 1;
}
return 0;
}- Julia: DataRead.jl
- R: haven