pub fn world_phones() -> Result<DataFrame, PolarsError>Expand description
§The World’s Telephones
§Description:
The number of telephones in various regions of the world (in thousands).
§Usage:
WorldPhones
§Format:
A matrix with 7 rows and 8 columns. The columns of the matrix give the figures for a given region, and the rows the figures for a year.
The regions are: North America, Europe, Asia, South America, Oceania, Africa, Central America.
The years are: 1951, 1956, 1957, 1958, 1959, 1960, 1961.
§Source:
AT&T (1961) The World’s Telephones.
§References:
McNeil, D. R. (1977) Interactive Data Analysis. New York: Wiley.
§Examples:
require(graphics)
matplot(rownames(WorldPhones), WorldPhones, type = "b", log = "y",
xlab = "Year", ylab = "Number of telephones (1000's)")
legend(1951.5, 80000, colnames(WorldPhones), col = 1:6, lty = 1:5,
pch = rep(21, 7))
title(main = "World phones data: log scale for response")