R version 2.13.0 (2011-04-13)
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ISBN 3-900051-07-0
Platform: i386-pc-mingw32/i386 (32-bit)

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> source("cv1.R")
Cviceni c. 1 
Na dalsi ukol se dostanete klavesou c nebo ENTER. 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> 

1. Vyzkousejte rozdily ve vypisech mezi definicemi vektoru "v": 
v <- c(1,2,3) a  
(v <- c(1,2,3)) 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> v <- c(1, 2, 3)   # bez vytisteni na obrazovku
Browse[1]> (v <- c(1, 2, 3))   # s vytistenim na obrazovku
[1] 1 2 3
Browse[1]> 

2. Dvema zpusoby zobrazte napovedu k funkci matrix, 
pomoci funce args() zjistete jeji argumenty. 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz
Browse[1]> # prikaz   ### argumenty funkce
function (data = NA, nrow = 1, ncol = 1, byrow = FALSE, dimnames = NULL) 
NULL
Browse[1]> 

3. Zjistete, ve kterem adresari se nachazite. 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz 
[1] "/home_stud/xkonecn3/vypsyst/cviceni_R"
Browse[1]> 

4. Vytvorte numericky vektor "x" s hodnotami 2, 4.7, 8, 3.1, 19, 7. 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz 
Browse[1]> x
[1]  2.0  4.7  8.0  3.1 19.0  7.0
Browse[1]> 

5. Vytvorte numericky vektor "y" s komplexnimi hodnotami 2, 5i, 3+i, 0.5+i. 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz
Browse[1]> y
[1] 2.0+0i 0.0+5i 3.0+1i 0.5+1i
Browse[1]> 

6. Vytvorte textovy vektor s nazvem "mesta" a slozkami "Praha", "Brno", 
"Ostrava", "Plzen", "Olomouc", "Karlovy Vary", "Liberec", "Ceske Budejovice",  
"Pardubice", "Most". 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz 
Browse[1]> mesta
 [1] "Praha"            "Brno"             "Ostrava"          "Plzen"           
 [5] "Olomouc"          "Karlovy Vary"     "Liberec"          "Ceske Budejovice"
 [9] "Pardubice"        "Most"            
Browse[1]> 

7. Vytvorte posloupnost "p" rozsahu 10 s pocatecni hodnotou 2 a krokem 2.5. 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz
Browse[1]> p
 [1]  2.0  4.5  7.0  9.5 12.0 14.5 17.0 19.5 22.0 24.5
Browse[1]> 

8. Vytvorte posloupnost "q" obsahujici 3, 2, ... -2, -3. 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz
Browse[1]> q
[1]  3  2  1  0 -1 -2 -3
Browse[1]> 

9. Vytvorte posloupnost "r" peti za sebou jdoucich nul a peti za sebou 
jdoucich jednicek. 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz
Browse[1]> r
 [1] 0 0 0 0 0 1 1 1 1 1
Browse[1]> 

10. Vytvorte posloupnost "s" petkrat za sebou se opakujicich nul a jednicek. 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz
Browse[1]> s
 [1] 0 1 0 1 0 1 0 1 0 1
Browse[1]> 

11. Nahodne vygenerujte pet nazvu mest z vektoru "mesta". 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz
[1] "Praha"        "Liberec"      "Pardubice"    "Brno"         "Karlovy Vary"
Browse[1]> 

12. Zjistete delku vektoru "mesta". 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz
[1] 10
Browse[1]> 

13. Pomoci funkce "sample" vygenerujte vektor "A", ktery bude obsahovat 
pet nazvu mest z vektoru "mesta":, 
   nejvyssi vahu (1) priradte mestu Praha, 
   vahy 0.5 priradte Brnu, Ostrave a Plzni, 
   ostatnim mestum priradte vahu 0.1. 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz
[1] "Praha"        "Ostrava"      "Brno"         "Olomouc"      "Karlovy Vary"
Browse[1]> 

14. Pomoci funkci "head" a "tail" priradte do jednoho vektoru "vyber" prvni ctyri a posledni dve mesta vektoru "mesta".  
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz
Browse[1]> vyber
[1] "Praha"     "Brno"      "Ostrava"   "Plzen"     "Pardubice" "Most"     
Browse[1]> 

15. Vypiste mesta na sudych pozicich vektoru "mesta" a pridejte k nim misto 
vaseho bydliste. 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz
[1] "Brno"             "Plzen"            "Karlovy Vary"     "Ceske Budejovice"
[5] "Most"             "Prusanky"

16. Vytvorte faktor "fact" se slozkami 0, 1, 1, 0, 1, 0, 0, 0, 1. 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz
Browse[1]> fact
[1] 0 1 1 0 1 0 0 0 1
Levels: 0 1
Browse[1]> 

17. Upravte faktor "fact" tak, aby se misto 0 vypisovalo "FALSE" a misto 1 
"TRUE". 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz
Browse[1]> fact
[1] FALSE TRUE  TRUE  FALSE TRUE  FALSE FALSE FALSE TRUE 
Levels: FALSE TRUE
Browse[1]> 

18. Vypiste seznam vsech nadefinovanych objektu. 
Zkuste nektery z nich smazat. Opet vypiste seznam vsech objektu. 
Called from: eval.with.vis(expr, envir, enclos)
Browse[1]> # prikaz
 [1] "A"         "fact"      "mesta"     "p"         "q"         "r"         "s"                 
 [8] "v"         "vyber"     "x"         "y"
Browse[1]> # prikaz   ### smazeme napr. obekty "fact", "p", "r"
Browse[1]> # prikaz   ### vypis
 [1] "A"         "mesta"     "q"         "s"         "v"         "vyber"     "x"         
 [8] "y"        
Browse[1]> 
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