How to create a time series by 30 minute intervals

Problem

We want to create a time series by 30 minute intervals.

Example

[1] "2017-01-01 00:00:00 UTC"
[2] "2017-01-01 00:30:00 UTC"
[3] "2017-01-01 01:00:00 UTC"
[4] "2017-01-01 01:30:00 UTC"
[5] "2017-01-01 02:00:00 UTC"
[6] "2017-01-01 02:30:00 UTC"

Solution

We use the function seq and specify minutes in the by argument, and pass the time zone "UTC". Type ?seq.POSIXt for more details about the by argument specified as a character string:

A character string, containing one of "sec", "min", "hour", "day", "DSTday", "week", "month", "quarter" or "year". This can optionally be preceded by a (positive or negative) integer and a space, or followed by "s".

seq(as.POSIXct("2017-01-01", tz = "UTC"),
    as.POSIXct("2017-01-02", tz = "UTC"),
    by = "30 min")

References

• stackoverflow

How to create a symmetric matrix in R

Problem

We want to create a symmetric matrix based on the following example.

Example

  V1 V2 V3 V4 V5
1  0  2  3  4  5
2  0  0  6  8 10
3  0  0  0 12 15
4  0  0  0  0 20
5  0  0  0  0  0

df <- structure(list(V1 = c(0L, 0L, 0L, 0L, 0L), V2 = c(2L, 0L, 0L, 
0L, 0L), V3 = c(3L, 6L, 0L, 0L, 0L), V4 = c(4L, 8L, 12L, 0L, 
0L), V5 = c(5L, 10L, 15L, 20L, 0L)), .Names = c("V1", "V2", "V3", 
"V4", "V5"), class = "data.frame", row.names = c("1", "2", "3", 
"4", "5"))

Solution

• Adding the transpose of the matrix.

df + t(df)

• Function lower.tri

We assign to the lower triangle of the matrix the transpose of the lower triangle.

df[lower.tri(df)] <- t(df)[lower.tri(df)]

  V1 V2 V3 V4 V5
1  0  2  3  4  5
2  2  0  6  8 10
3  3  6  0 12 15
4  4  8 12  0 20
5  5 10 15 20  0

Using upper.tri would not create a symmetrical matrix.

df[lower.tri(df)] <- df[upper.tri(df)]

  V1 V2 V3 V4 V5
1  0  2  3  4  5
2  2  0  6  8 10
3  3  8  0 12 15
4  6 12 10  0 20
5  4  5 15 20  0

References

• stackoverflow

How to change the spacing between the legend and the panel in ggplot2

Problema

We want to increase the spacing between the legend and the panel in ggplot2.

library(ggplot2)
xy <- data.frame(x = 1:10, y = 10:1, type = rep(LETTERS[1:2], each=5))
plot <- ggplot(data = xy) +
        geom_point(aes(x = x, y = y, colo r= type))

Solution

We use the argument legend.box.margin to add 20 points to the left.

plot <- plot + theme(legend.box.margin = margin(0, 0, 0, 20))

References

• stackoverflow

Cómo eliminar todos los comentarios en Excel

Problema

Queremos borrar todos los comentarios en Excel. Veremos tres alternativas, en la última usaremos VBA

Solución

• Opción 1
1. En la pestaña Revisar clic en Mostrar todos los comentarios

2. Press Ctrl+E para seleccionar todos los comentarios
3. Clic en Eliminar

• Opción 2
1. Presionamos F5 o Ctrl + I para abrir el cuadro de diálogo Ir a, clic en Especial

2. Todos los comentarios serán seleccionados

3. Clic con el botón derecho para abrir el menú contextual y clic en Eliminar comentario

• Opción 3 - VBA
1. Borra todos los comentarios de la hoja activa

Sub Borra_Comentarios_de_la_Hoja()
 Cells.ClearComments
End Sub

2. Borra todos los comentarios del libro de Excel

Sub Borra_todos_los_Comentarios()
    Dim ws As Worksheet

    For Each ws In Worksheets
        ws.UsedRange.ClearComments
    Next

End Sub

How to remove all comments in Excel

Problem

We want to delete all comments in Excel. We will see three alternative, the last one using VBA.

Solution

• Option 1
1. On the Review tab click on Show all comments

2. Press Ctrl+A to select all comments
3. Click on Delete

• Option 2
1. Press F5 or Ctrl + G to open Go To dialog box, click on Special and then OK

2. All comments will be selected

3. Right click to open context menu and click on Delete Comment

• Option 3 - VBA
1. Delete all comments from active sheet

Sub Delete_Comments_from_Sheet()
 Cells.ClearComments
End Sub

2. Delete all comments from the workbook

Sub Delete_All_Comments()
    Dim ws As Worksheet

    For Each ws In Worksheets
        ws.UsedRange.ClearComments
    Next

End Sub

How to modify whiskers of a boxplot in ggplot2?

Problem

We want to modify the colour of the whiskers in a boxplot using ggplot2. In our example, the default colour (black) to red.

library(ggplot2)
p <- ggplot(mtcars, aes(factor(cyl), mpg, fill = factor(am)))
p + geom_boxplot()

Solution

• Option 1

We plot error bars in red and then superimpose the boxplots in black.

library(ggplot)
p + stat_boxplot(
  geom = "errorbar",
  colour = "red",
  width = 0,
  position = position_dodge(0.75)
) +
  geom_boxplot(coef = 0, outlier.shape = NA)


• Option 2

We superimpose two boxplots on top of each other. The first one with red borders and the secong one without whiskers in black.

p + geom_boxplot(color="red") + 
  geom_boxplot(aes(ymin=..lower.., ymax=..upper..)) 

References

• Box and whiskers plot.
• stackoverflow

Cómo reducir el espacio entre barras de un diagramas de barra con ggplot2

Problema

Queremos reducir el espacio entre las barras de un diagrama de barras con ggplot2.

Diagrama de barras vertical

Diagrama de barras horizontal

library(ggthemes)
library(ggplot2)
df <- data.frame(x = c("firm", "vendor"), y = c(50, 20))

# Vertical
ggplot(df, aes(x = x, y = y)) + 
  geom_bar(stat = "identity", width = 0.4) + 
  theme_tufte() + 
  labs(x = "", y = "")

# Horizontal
ggplot(df, aes(x = x, y = y)) + 
  geom_bar(stat = "identity", width = 0.4) + 
  theme_tufte() +  coord_flip() +
  labs(x = "", y = "")

Solución

Tan sólo necesitamos añadir theme(aspect.ratio = xx), y luego necesitamos ajustar el ese ratio para conseguir las distancia deseada. Con coord_flip() podemos voltear el gráfico

# Vertical
ggplot(df, aes(x = x, y = y)) + 
  geom_bar(stat = "identity") + 
  theme_tufte() + theme(aspect.ratio = 2) +
  labs(x = "", y = "")

# Horizontal
ggplot(df, aes(x = x, y = y)) + 
  geom_bar(stat = "identity") + 
  theme_tufte() + theme(aspect.ratio = .2) +
  coord_flip() +
  labs(x = "", y = "")

Resultados

Diagrama de barras vertical

Diagrama de barras horizontal