# [R] Fwd: Help with looping a function over a list of dataframes:

Kathan Desai kde@@|1 @end|ng |rom @he|||e|d@@c@uk
Sat Jul 4 16:54:32 CEST 2020

```*I hope this is more succinct.*

*I have the following code: *
list_df\$position_tab_5\$ID <- unlist(lapply(list_df\$position_tab_5\$midpoint,
function(x) ifelse(any(abs(x - list_df\$position_tab_4\$midpoint) <= 1),1,0)))

It compares every observation from the midpoint column from dataframe 2 to
every observation from the midpoint column from dataframe 1. It does this
in order to find any values within +/- 1 of the value, and if it satisfies
this criteria then it assigns it a unique id of 1. If not then a value of
0.

In the example below, pos_tab_5 is being compared to pos_tab_4:

Pos tab 4:
Object minimum maximum midpoint
2600    4             22             13
2604    42           85             63.5
2606    142         172           157
2609    223         241           232
2611    393         421           407

Pos tab 5:
Object minimum maximum midpoint ID
2580    3             21             12           1
2581    43           85             64           1
2585    132         168           150         0
2586    223         241           232         1
2589    391         419           405         0

The reason it compares every observation from pos_tab_(n) to pos_tab_(n-1)
is because some of the dataframes are of different row length, and so by
comparing every observation from one DF to another, it can find any values
that are within +/- 1 of each other. (which is the main thing i'm looking
for)

I need help looping this function over a list of dataframes. The list of
dataframes called: list_df contains 121 different dataframes all
representing a different time point of the object.

This is what i have so far:
for(i in seq_along(list_df)){
list_df\$position_tab_[[i]]\$ID <-
unlist(lapply(list_df\$position_tab_[[i]]\$midpoint, function(x)
ifelse(any(abs(x - list_df\$position_tab_[[i-1]]\$midpoint)
<= 1),1,0)
))
}

On Sat, 4 Jul 2020 at 14:44, Eric Berger <ericjberger using gmail.com> wrote:

> Hi Kathan,
> How about trying to create a *minimal* reproducible example, e.g. with a
> list of two data frames, where each data frame has 5 rows,?
> My guess is that there is a good chance that when you try to create such
> an example, you will discover the problem yourself.
> In the event that you create the example but still cannot solve your
> issue, you will find more people on this list willing to look into your
> question, as it will be much faster for them to do that (compared to the
> original formulation.)
>
> Eric
>
>
> On Sat, Jul 4, 2020 at 4:33 PM Kathan Desai <kdesai1 using sheffield.ac.uk>
> wrote:
>
>> ---------- Forwarded message ---------
>> From: Kathan Desai <kdesai1 using sheffield.ac.uk>
>> Date: Sat, 4 Jul 2020 at 14:31
>> Subject: Re: [R] Help with looping a function over a list of dataframes:
>> To: Jim Lemon <drjimlemon using gmail.com>
>>
>>
>> Hi Jim,
>>
>> Thankyou for your reply, I tried the function you suggested and it
>> doesn't seem to work. There are again no error messages produced, however
>> the transformation to each position_tab_n table isn't being applied.
>>
>> Cheers,
>> Kathan
>>
>>
>> On Sat, 4 Jul 2020 at 11:14, Jim Lemon <drjimlemon using gmail.com> wrote:
>>
>> > Hi Kathan,
>> > This is a very lazy answer as I haven't tested it. I think you will
>> > need to wrap your loop in a function and return the modified list_df
>> > to assign it like this:
>> >
>> >  for(i in seq_along(xdf)) {
>> >   xdf\$position_tab_[[i]]\$ID <-
>> >    unlist(lapply(xdf\$position_tab_[[i]]\$midpoint, function(x)
>> >     ifelse(any(abs(x - xdf\$position_tab_[[i-1]]\$midpoint)<= 1),1,0)))
>> >  }
>> >  return(xdf)
>> > }
>> >
>> > Jim
>> >
>> > On Sat, Jul 4, 2020 at 4:48 PM Kathan Desai <kdesai1 using sheffield.ac.uk>
>> > wrote:
>> > >
>> > > I have been trying to run a forloop for a function that compares
>> > dataframe n
>> > > with dataframe n-1, across a list of dataframes. It does this by
>> checking
>> > > each midpoint of dataframe n with each midpoint of dataframe n-1.
>> This is
>> > > done to make up for an disparity in row length. The idea of this code
>> is
>> > to
>> > > identify any objects that are stationary, and assign them an id of 1,
>> and
>> > > the dynamic objects are assigned an id of 0 (examples can be found
>> > below).
>> > >
>> > >
>> > > *This is what i have so far:*
>> > > for(i in seq_along(list_df)){
>> > >    list_df\$position_tab_[[i]]\$ID <-
>> > >      unlist(lapply(list_df\$position_tab_[[i]]\$midpoint, function(x)
>> > >                  ifelse(any(abs(x -
>> > list_df\$position_tab_[[i-1]]\$midpoint)
>> > > <= 1),1,0)
>> > >             ))
>> > > }
>> > >
>> > > There is no error message being produced so theres nothing to debug,
>> i am
>> > > quite new to R programming in general so excuse any silly mistakes i
>> may
>> > > have made. The function doesnt seem to be adding the ID columns and
>> > > comparing the data as it should.
>> > >
>> > > my list of dataframes contain dataframes named: position_tab_1,
>> > > position_tab_2 .... position_tab_121. Each position_tab represents a
>> > > timepoints, so in total there are 121 timepoints (frames). I need the
>> > loop
>> > > to run so that pos_tab_2 compares to pos_tab_1 and this continues all
>> the
>> > > way to pos_tab_121 comparing to pos_tab_120.
>> > >
>> > > The function adds a column named "id" to each of these dataframes as
>> it
>> > > compares to the dataframe before it, so all dataframes apart from
>> > > position_tab_1 (as it has nothing to compare to) should have this
>> > >
>> > >
>> > > *Some of my data (first 10 dataframes in list):*
>> > > > dput(list_df[1:10])
>> > > list(position_tab_1 = structure(list(Object = c(2666L, 2668L,
>> > > 2671L, 2674L, 2676L, 2677L, 2678L, 2679L, 2680L, 2682L, 2683L,
>> > > 2684L, 2685L, 2686L, 2687L, 2689L, 2692L, 2693L, 2694L, 2695L,
>> > > 2696L), minimum = c(4L, 39L, 147L, 224L, 419L, 531L, 595L, 641L,
>> > > 669L, 723L, 810L, 836L, 907L, 978L, 1061L, 1129L, 1290L, 1519L,
>> > > 1749L, 1843L, 1897L), maximum = c(22L, 85L, 173L, 242L, 449L,
>> > > 587L, 627L, 655L, 702L, 740L, 828L, 890L, 923L, 1024L, 1086L,
>> > > 1144L, 1302L, 1544L, 1780L, 1870L, 1925L), midpoint = c(13, 62,
>> > > 160, 233, 434, 559, 611, 648, 685.5, 731.5, 819, 863, 915, 1001,
>> > > 1073.5, 1136.5, 1296, 1531.5, 1764.5, 1856.5, 1911)), row.names =
>> c(NA,
>> > > -21L), class = c("tbl_df", "tbl", "data.frame")), position_tab_2 =
>> > > structure(list(
>> > >     Object = c(2645L, 2646L, 2650L, 2652L, 2655L, 2656L, 2657L,
>> > >     2658L, 2659L, 2661L, 2662L, 2663L, 2664L, 2665L, 2667L, 2670L,
>> > >     2675L, 2681L, 2688L, 2690L, 2691L), minimum = c(4L, 40L,
>> > >     147L, 224L, 415L, 532L, 595L, 641L, 670L, 722L, 811L, 835L,
>> > >     907L, 978L, 1061L, 1128L, 1289L, 1520L, 1748L, 1843L, 1897L
>> > >     ), maximum = c(22L, 85L, 173L, 242L, 445L, 588L, 627L, 655L,
>> > >     702L, 739L, 828L, 891L, 923L, 1022L, 1085L, 1143L, 1302L,
>> > >     1544L, 1779L, 1870L, 1925L), midpoint = c(13, 62.5, 160,
>> > >     233, 430, 560, 611, 648, 686, 730.5, 819.5, 863, 915, 1000,
>> > >     1073, 1135.5, 1295.5, 1532, 1763.5, 1856.5, 1911)), row.names =
>> c(NA,
>> > > -21L), class = c("tbl_df", "tbl", "data.frame")), position_tab_3 =
>> > > structure(list(
>> > >     Object = c(2623L, 2624L, 2627L, 2631L, 2633L, 2635L, 2636L,
>> > >     2637L, 2638L, 2640L, 2641L, 2642L, 2643L, 2644L, 2647L, 2649L,
>> > >     2654L, 2660L, 2669L, 2672L, 2673L), minimum = c(3L, 39L,
>> > >     149L, 223L, 402L, 539L, 594L, 639L, 669L, 722L, 811L, 834L,
>> > >     907L, 979L, 1060L, 1129L, 1289L, 1520L, 1749L, 1842L, 1897L
>> > >     ), maximum = c(22L, 86L, 175L, 241L, 431L, 587L, 627L, 653L,
>> > >     700L, 738L, 828L, 894L, 925L, 1021L, 1084L, 1144L, 1302L,
>> > >     1544L, 1779L, 1869L, 1925L), midpoint = c(12.5, 62.5, 162,
>> > >     232, 416.5, 563, 610.5, 646, 684.5, 730, 819.5, 864, 916,
>> > >     1000, 1072, 1136.5, 1295.5, 1532, 1764, 1855.5, 1911)), row.names
>> =
>> > > c(NA,
>> > > -21L), class = c("tbl_df", "tbl", "data.frame")), position_tab_4 =
>> > > structure(list(
>> > >     Object = c(2600L, 2604L, 2606L, 2609L, 2611L, 2613L, 2614L,
>> > >     2615L, 2617L, 2618L, 2619L, 2620L, 2621L, 2622L, 2626L, 2628L,
>> > >     2632L, 2639L, 2648L, 2651L, 2653L), minimum = c(4L, 42L,
>> > >     142L, 223L, 393L, 547L, 595L, 641L, 669L, 720L, 809L, 835L,
>> > >     908L, 979L, 1059L, 1127L, 1289L, 1519L, 1749L, 1841L, 1897L
>> > >     ), maximum = c(22L, 85L, 172L, 241L, 421L, 587L, 629L, 655L,
>> > >     701L, 738L, 826L, 890L, 925L, 1019L, 1084L, 1143L, 1301L,
>> > >     1544L, 1780L, 1868L, 1925L), midpoint = c(13, 63.5, 157,
>> > >     232, 407, 567, 612, 648, 685, 729, 817.5, 862.5, 916.5, 999,
>> > >     1071.5, 1135, 1295, 1531.5, 1764.5, 1854.5, 1911)), row.names =
>> c(NA,
>> > > -21L), class = c("tbl_df", "tbl", "data.frame")), position_tab_5 =
>> > > structure(list(
>> > >     Object = c(2580L, 2581L, 2585L, 2586L, 2589L, 2590L, 2592L,
>> > >     2593L, 2594L, 2595L, 2596L, 2597L, 2598L, 2599L, 2601L, 2603L,
>> > >     2605L, 2610L, 2616L, 2625L, 2629L, 2630L, 2634L), minimum = c(3L,
>> > >     43L, 132L, 223L, 391L, 547L, 643L, 669L, 721L, 808L, 836L,
>> > >     861L, 908L, 978L, 1028L, 1057L, 1127L, 1288L, 1519L, 1748L,
>> > >     1842L, 1893L, 2148L), maximum = c(21L, 85L, 168L, 241L, 419L,
>> > >     629L, 656L, 701L, 738L, 828L, 858L, 890L, 925L, 1013L, 1050L,
>> > >     1083L, 1143L, 1301L, 1544L, 1780L, 1869L, 1925L, 2148L),
>> > >     midpoint = c(12, 64, 150, 232, 405, 588, 649.5, 685, 729.5,
>> > >     818, 847, 875.5, 916.5, 995.5, 1039, 1070, 1135, 1294.5,
>> > >     1531.5, 1764, 1855.5, 1909, 2148)), row.names = c(NA, -23L
>> > > ), class = c("tbl_df", "tbl", "data.frame")), position_tab_6 =
>> > > structure(list(
>> > >     Object = c(2555L, 2559L, 2562L, 2563L, 2564L, 2567L, 2569L,
>> > >     2570L, 2571L, 2572L, 2573L, 2574L, 2575L, 2576L, 2577L, 2579L,
>> > >     2583L, 2587L, 2591L, 2602L, 2607L, 2608L, 2612L), minimum = c(4L,
>> > >     45L, 123L, 154L, 224L, 390L, 546L, 600L, 643L, 669L, 720L,
>> > >     804L, 836L, 908L, 967L, 1058L, 1129L, 1289L, 1519L, 1748L,
>> > >     1843L, 1893L, 2147L), maximum = c(23L, 86L, 150L, 171L, 241L,
>> > >     419L, 589L, 636L, 657L, 701L, 738L, 827L, 879L, 925L, 1011L,
>> > >     1084L, 1144L, 1301L, 1543L, 1780L, 1871L, 1924L, 2148L),
>> > >     midpoint = c(13.5, 65.5, 136.5, 162.5, 232.5, 404.5, 567.5,
>> > >     618, 650, 685, 729, 815.5, 857.5, 916.5, 989, 1071, 1136.5,
>> > >     1295, 1531, 1764, 1857, 1908.5, 2147.5)), row.names = c(NA,
>> > > -23L), class = c("tbl_df", "tbl", "data.frame")), position_tab_7 =
>> > > structure(list(
>> > >     Object = c(2537L, 2539L, 2540L, 2541L, 2542L, 2544L, 2546L,
>> > >     2547L, 2548L, 2549L, 2550L, 2551L, 2552L, 2554L, 2556L, 2558L,
>> > >     2560L, 2565L, 2568L, 2578L, 2582L, 2584L, 2588L), minimum = c(3L,
>> > >     45L, 122L, 156L, 224L, 387L, 546L, 601L, 669L, 719L, 803L,
>> > >     837L, 908L, 959L, 1059L, 1096L, 1128L, 1289L, 1519L, 1748L,
>> > >     1844L, 1892L, 2147L), maximum = c(22L, 86L, 147L, 172L, 241L,
>> > >     415L, 590L, 656L, 699L, 738L, 830L, 871L, 924L, 1014L, 1082L,
>> > >     1119L, 1144L, 1301L, 1543L, 1781L, 1872L, 1925L, 2148L),
>> > >     midpoint = c(12.5, 65.5, 134.5, 164, 232.5, 401, 568, 628.5,
>> > >     684, 728.5, 816.5, 854, 916, 986.5, 1070.5, 1107.5, 1136,
>> > >     1295, 1531, 1764.5, 1858, 1908.5, 2147.5)), row.names = c(NA,
>> > > -23L), class = c("tbl_df", "tbl", "data.frame")), position_tab_8 =
>> > > structure(list(
>> > >     Object = c(2514L, 2517L, 2519L, 2520L, 2521L, 2523L, 2525L,
>> > >     2526L, 2527L, 2528L, 2529L, 2530L, 2531L, 2532L, 2533L, 2534L,
>> > >     2536L, 2543L, 2545L, 2553L, 2557L, 2561L, 2566L), minimum = c(5L,
>> > >     44L, 121L, 153L, 224L, 380L, 546L, 603L, 668L, 721L, 802L,
>> > >     841L, 907L, 960L, 1006L, 1060L, 1106L, 1288L, 1518L, 1748L,
>> > >     1843L, 1893L, 2148L), maximum = c(23L, 86L, 146L, 170L, 242L,
>> > >     409L, 588L, 655L, 699L, 738L, 830L, 872L, 924L, 994L, 1029L,
>> > >     1084L, 1143L, 1302L, 1543L, 1781L, 1870L, 1925L, 2148L),
>> > >     midpoint = c(14, 65, 133.5, 161.5, 233, 394.5, 567, 629,
>> > >     683.5, 729.5, 816, 856.5, 915.5, 977, 1017.5, 1072, 1124.5,
>> > >     1295, 1530.5, 1764.5, 1856.5, 1909, 2148)), row.names = c(NA,
>> > > -23L), class = c("tbl_df", "tbl", "data.frame")), position_tab_9 =
>> > > structure(list(
>> > >     Object = c(2492L, 2493L, 2497L, 2498L, 2499L, 2501L, 2503L,
>> > >     2504L, 2505L, 2506L, 2507L, 2508L, 2509L, 2510L, 2511L, 2513L,
>> > >     2516L, 2522L, 2524L, 2532L, 2535L, 2538L), minimum = c(6L,
>> > >     44L, 111L, 149L, 224L, 375L, 548L, 596L, 668L, 722L, 800L,
>> > >     840L, 908L, 960L, 1005L, 1058L, 1127L, 1289L, 1519L, 1748L,
>> > >     1842L, 1891L), maximum = c(24L, 81L, 137L, 167L, 242L, 403L,
>> > >     589L, 656L, 699L, 738L, 828L, 872L, 925L, 994L, 1028L, 1081L,
>> > >     1149L, 1302L, 1544L, 1780L, 1868L, 1924L), midpoint = c(15,
>> > >     62.5, 124, 158, 233, 389, 568.5, 626, 683.5, 730, 814, 856,
>> > >     916.5, 977, 1016.5, 1069.5, 1138, 1295.5, 1531.5, 1764, 1855,
>> > >     1907.5)), row.names = c(NA, -22L), class = c("tbl_df", "tbl",
>> > > "data.frame")), position_tab_10 = structure(list(Object = c(2469L,
>> > > 2471L, 2474L, 2475L, 2476L, 2478L, 2481L, 2482L, 2483L, 2484L,
>> > > 2485L, 2486L, 2487L, 2488L, 2489L, 2491L, 2495L, 2500L, 2502L,
>> > > 2512L, 2515L, 2518L), minimum = c(6L, 38L, 109L, 147L, 223L,
>> > > 363L, 548L, 597L, 668L, 719L, 803L, 839L, 908L, 958L, 1004L,
>> > > 1058L, 1126L, 1288L, 1519L, 1746L, 1841L, 1892L), maximum = c(24L,
>> > > 76L, 134L, 165L, 240L, 394L, 591L, 656L, 698L, 737L, 829L, 869L,
>> > > 924L, 996L, 1027L, 1081L, 1147L, 1301L, 1543L, 1781L, 1868L,
>> > > 1925L), midpoint = c(15, 57, 121.5, 156, 231.5, 378.5, 569.5,
>> > > 626.5, 683, 728, 816, 854, 916, 977, 1015.5, 1069.5, 1136.5,
>> > > 1294.5, 1531, 1763.5, 1854.5, 1908.5)), row.names = c(NA, -22L
>> > > ), class = c("tbl_df", "tbl", "data.frame")))
>> > >
>> > > *What is produced when running the base code without any loops:*
>> > >
>> > > This is the base code without me trying to loop it in anyway, below is
>> > what
>> > > it produces when its used with dataframe 4 and 5:
>> > >
>> > > #the code:
>> > > list_df\$position_tab_5\$ID <-
>> > unlist(lapply(list_df\$position_tab_5\$midpoint,
>> > > function(x) ifelse(any(abs(x - list_df\$position_tab_4\$midpoint) <=
>> > 1),1,0)))
>> > >
>> > > ##position_tab_5 after manipulations have occured:
>> > > structure(list(Object = c(2580L, 2581L, 2585L, 2586L, 2589L,
>> > > 2590L, 2592L, 2593L, 2594L, 2595L, 2596L, 2597L, 2598L, 2599L,
>> > > 2601L, 2603L, 2605L, 2610L, 2616L, 2625L, 2629L, 2630L, 2634L
>> > > ), minimum = c(3L, 43L, 132L, 223L, 391L, 547L, 643L, 669L, 721L,
>> > > 808L, 836L, 861L, 908L, 978L, 1028L, 1057L, 1127L, 1288L, 1519L,
>> > > 1748L, 1842L, 1893L, 2148L), maximum = c(21L, 85L, 168L, 241L,
>> > > 419L, 629L, 656L, 701L, 738L, 828L, 858L, 890L, 925L, 1013L,
>> > > 1050L, 1083L, 1143L, 1301L, 1544L, 1780L, 1869L, 1925L, 2148L
>> > > ), midpoint = c(12, 64, 150, 232, 405, 588, 649.5, 685, 729.5,
>> > > 818, 847, 875.5, 916.5, 995.5, 1039, 1070, 1135, 1294.5, 1531.5,
>> > > 1764, 1855.5, 1909, 2148), ID = c(1, 1, 0, 1, 0, 0, 0, 1, 1,
>> > > 1, 0, 0, 1, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0)), row.names = c(NA,
>> > > -23L), class = c("tbl_df", "tbl", "data.frame"))
>> > >
>> > > #position_tab_4 (the DF pos_tab_5 is being compared to)
>> > > structure(list(Object = c(2600L, 2604L, 2606L, 2609L, 2611L,
>> > > 2613L, 2614L, 2615L, 2617L, 2618L, 2619L, 2620L, 2621L, 2622L,
>> > > 2626L, 2628L, 2632L, 2639L, 2648L, 2651L, 2653L), minimum = c(4L,
>> > > 42L, 142L, 223L, 393L, 547L, 595L, 641L, 669L, 720L, 809L, 835L,
>> > > 908L, 979L, 1059L, 1127L, 1289L, 1519L, 1749L, 1841L, 1897L),
>> > >     maximum = c(22L, 85L, 172L, 241L, 421L, 587L, 629L, 655L,
>> > >     701L, 738L, 826L, 890L, 925L, 1019L, 1084L, 1143L, 1301L,
>> > >     1544L, 1780L, 1868L, 1925L), midpoint = c(13, 63.5, 157,
>> > >     232, 407, 567, 612, 648, 685, 729, 817.5, 862.5, 916.5, 999,
>> > >     1071.5, 1135, 1295, 1531.5, 1764.5, 1854.5, 1911)), row.names =
>> c(NA,
>> > > -21L), class = c("tbl_df", "tbl", "data.frame"))
>> > >
>> > > *Appreciate any help, anyone can provide!*
>> > >
>> > >         [[alternative HTML version deleted]]
>> > >
>> > > ______________________________________________
>> > > R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> > > https://stat.ethz.ch/mailman/listinfo/r-help
>> > http://www.R-project.org/posting-guide.html
>> > > and provide commented, minimal, self-contained, reproducible code.
>> >
>>
>>         [[alternative HTML version deleted]]
>>
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