Avoid Truncated List Output of str Function in R (Example) | Expand Listed Variables

In this article you’ll learn how to expand listed variables using the str() function in the R programming language.

The article consists of this content:

Let’s dive right in:

Introducing Example Data

The first step is to create some data that we can use in the examples later on:

data <- as.data.frame(matrix(1:600, nrow = 5))    # Create example data frame
data[ , 1:5]                                      # Print five columns of data

Table 1 visualizes the output of the RStudio console that has been returned after running the previous R syntax and shows the structure of the first five variables of our example data.

Note that we have subsetted our data frame in the previous Table. The entire data frame contains 120 columns!

Let’s assume that we want to inspect the structure of our data frame variables using the str function. Then, we might apply the following R code:

str(data)                                         # Apply str function
# 'data.frame':	5 obs. of  120 variables:
#  ...
#  $ V94 : int  466 467 468 469 470
#  $ V95 : int  471 472 473 474 475
#  $ V96 : int  476 477 478 479 480
#  $ V97 : int  481 482 483 484 485
#  $ V98 : int  486 487 488 489 490
#  $ V99 : int  491 492 493 494 495
#   [list output truncated]

The output after executing the previous R code shows the structure of the first 99 variables in our data set. However, the remaining list output of the str function has been truncated.

Example: Avoid Truncation Using str() Function & list.len Argument

This example demonstrates how to display the entire list output when using the str function in R, i.e. without truncating the bottom part of the list.

To achieve this, we have to set the list.len argument within the str function to be equal to the number of columns in our data frame.

Consider the following R code and its output:

str(data, list.len = ncol(data))                  # str function & list.len
# 'data.frame':	5 obs. of  120 variables:
#  ...
#  $ V94 : int  466 467 468 469 470
#  $ V95 : int  471 472 473 474 475
#  $ V96 : int  476 477 478 479 480
#  $ V97 : int  481 482 483 484 485
#  $ V98 : int  486 487 488 489 490
#  $ V99 : int  491 492 493 494 495
#  $ V100: int  496 497 498 499 500
#  $ V101: int  501 502 503 504 505
#  $ V102: int  506 507 508 509 510
#  $ V103: int  511 512 513 514 515
#  $ V104: int  516 517 518 519 520
#  $ V105: int  521 522 523 524 525
#  $ V106: int  526 527 528 529 530
#  $ V107: int  531 532 533 534 535
#  $ V108: int  536 537 538 539 540
#  $ V109: int  541 542 543 544 545
#  $ V110: int  546 547 548 549 550
#  $ V111: int  551 552 553 554 555
#  $ V112: int  556 557 558 559 560
#  $ V113: int  561 562 563 564 565
#  $ V114: int  566 567 568 569 570
#  $ V115: int  571 572 573 574 575
#  $ V116: int  576 577 578 579 580
#  $ V117: int  581 582 583 584 585
#  $ V118: int  586 587 588 589 590
#  $ V119: int  591 592 593 594 595
#  $ V120: int  596 597 598 599 600

As you can see, this time the entire list has been returned to the RStudio console.

Video & Further Resources

In case you need more info on the content of this tutorial, I recommend watching the following video on my YouTube channel. In the video, I’m explaining the R syntax of this article in R.

The YouTube video will be added soon.

Furthermore, you might read the other tutorials on this website:

• Print Table in R
• str_trunc Function in R
• List of R Functions (Examples)
• All R Programming Tutorials

To summarize: In this R tutorial you have learned how to avoid truncation in the str function. In case you have any further questions, please let me know in the comments section below.